Volume estimation in a Eucalyptus plantation using multi-source remote sensing and digital terrain data: a case study in Minas Gerais State,Brazil

In this study, we tested the effectiveness of stand age, multispectral optical imagery obtained from the Landsat 8 Operational Land Imager (OLI), synthetic aperture radar (SAR) data acquired by the Sentinel-1B satellite, and digital terrain attributes extracted from a digital elevation model (DEM), in estimating forest volume in 351 plots in a 1,498 ha Eucalyptus plantation in northern Minas Gerais state, Brazil. A Random Forest (RF) machine learning algorithm was used following the Principal Component Analysis (PCA) of various data combinations, including multispectr al and SAR texture variables and DEM-based geomorphometric derivatives. Using multispectral, SAR or DEM variables alone (i.e. Experiments (ii)–(iv)) did not provide accurate estimates of volume (RMSE (Root Mean Square Error) > 32.00 m³ ha^?1) compared to predictions based on age since planting of Eucalyptus stands (Experiment (i)). However, when these datasets were individually combined with stand age (i.e. Experiments (v)–(vii)), the RF models resulted in better volume estimates than those obtained when using the individual multispectral, SAR and DEM datasets (RMSE < 28.00 m³ ha^?1). Furthermore, a model that integrated the selected variables of these data with stand age (Experiment (viii)) improved volume estimation significantly (RMSE = 22.33 m³ ha^?1). The large and increasing area of Eucalyptus forest plantations in Brazil and elsewhere suggests that this new approach to volume estimation has the potential to support Eucalyptus plantation monitoring and forest management practices.     

Formation Maneuvering and Target Interception for Multi‐Agent Systems via Rigid Graphs

In this paper, we introduce control laws for multi‐agent formation maneuvering and target interception problems. In the target interception problem, we consider that the target velocity is unknown. Using a single‐integrator agent model, the proposed controls consist of a formation acquisition term, dependent on the graph rigidity matrix, and a formation maneuvering or target interception term. The control laws are only a function of the relative position of agents in an infinitesimally and minimally rigid graph, and either the desired maneuvering velocity of the formation or the target's relative position to the leader. The target interception control includes a continuous dynamic estimation term to identify the unknown target velocity. A Lyapunov‐like stability analysis is used to prove that the control objectives are met.     

Smart composite useful to acid release

This work presents a smart composite prepared using a resin based on cardanol and furfural, filled with Al₂O₃. This material is inert at room temperature. However, it is able to release an active substance after a certain temperature is reached. The obtained materials were characterized by Fourier transform spectroscopy, X‐ray diffraction, scanning electron microscopy, thermal gravimetric analysis, and differential scanning calorimetry. In addition, cure degree and acid‐release tests were performed. According to the obtained data, acid is trapped inside the composites, remaining inactive in the structure while the melting temperature of the hydrophobic shell is not reached. After it is, acid is released and the pH decreases. Therefore, this smart composite could be useful in speeding up drilling in sedimentary rocks with a combination of chemical (acid release) and physical (mechanical wear) mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43071.     

Synthesis and self‐assembly study of zwitterionic amphiphilic derivatives of chitosan

New zwitterionic derivatives of chitosan (CH) were synthesized through the Michael addition reaction of 1‐(3‐sulfopropyl)‐2‐vinylpyridine hydroxide (SPP) with primary amines of deacetylated CHs (with weight‐average molecular weights of 46 and 216 kDa) to obtain SPP‐substituted CHs. The hydrophilic derivatives were subsequently modified with 2.1, 4.6, and 9.7% of dodecyl groups [degree of substitution by dodecyl groups (DS_Dod)]. The SPP‐substituted CH derivatives were characterized by ¹H‐NMR, Fourier transform infrared spectroscopy, and gel permeation chromatography. Aqueous solutions of SPP‐substituted CH samples remained clear, independently of the pH (3.0 < pH < 12.0). The self‐association study of the amphiphilic derivatives was performed in aqueous buffered solution at pH 5.0 and 7.4, and the critical aggregation concentration values varied from 5.6 × 10^?3 to 0.02 g/L. The measurements of dynamic light scattering and ζ potentials showed that the self‐assembly behavior was dependent on the pH and DS_Dod. At pH 7.4, the measured ζ potentials were near zero, and colloidal stability was provided by the hydrated zwitterionic shell of the aggregates. Transmission electron microscopy revealed spherelike microsized particles of broad distribution. The amphiphilic SPP‐substituted CH samples were shown to be nontoxic with a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay performed with HeLa cells. The remarkable water solubility and nontoxicity displayed by the new SPP‐substituted CH derivatives showed promising properties for the design of CH‐based biomaterials and nanoparticles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44176.     

An hybrid evolutionary multiobjective algorithm for multiuser margin maximization in DSL

This work describes and proposes the application of evolutionary algorithms on the multiuser spectrum and SNR margin optimization problem for multicarrier systems, such as digital subscriber line. The proposed method is designed such that it takes advantage of special characteristics of the well‐known power adaptation techniques and uses them to solve the broader and more challenging problem of multiuser margin adaptation. Simulations show that the proposed method provides Pareto‐optimal and diverse solutions when compared to a previous method to solve the same problem. Copyright © 2014 John Wiley & Sons, Ltd.     

Bank filtration in a coastal lake in South Brazil: water quality,natural organic matter (NOM) and redox conditions study

Bank filtration (BF) was evaluated as new treatment or pre-treatment option for drinking water production in Brazil. General water quality parameters, natural organic matter (NOM) and redox conditions were evaluated in Lagoa do Peri, a costal lake in Santa Catarina, South Brazil. Studies in two periods at two bank filtrations well systems, in a 45-m-length column and in a test filter laboratory scale set-up, were performed. The well systems and the column showed the removal of turbidity and colour from around 7 NTU and 65 Pt–Co, respectively, to below the local regulations (1 NTU and 15 Pt–Co units). Both systems demonstrated a good removal of NOM and trihalomethanes (THM) precursors with a preference removal of THM precursors. The NOM and THM precursor removal in the large column and the test filter were effectively modelled. In both cases, an easily degradable organic matter fraction was modelled; in the large column a moderate degradable fraction was identified as well. The first fraction was removed during the first days of travel time of the bank filtrate. A change to reduced redox conditions was observed in the large column experiment. The same happened in the wells system, showing the dissolution of iron, manganese and sulphide in the bank filtrate. This was the principal drawback of BF comparing with the already existing direct filtration (DF) treatment plant. BF performed slightly better in THM precursor removal (52%) than DF (42%). Therefore, BF could be a pre-treatment for the DF treatment system, and the existing facility could be adapted for iron and manganese removal.     

Comparative studies on parametric sensitivity analyses using conventional and factorial design methodologies: mathematical modelling of clavulanic acid adsorption on zeolites

BACKGROUND: The main objective of this work was to evaluate the parametric sensitivity of model parameters of clavulanic acid (CA) adsorption in a stirred‐tank reactor using zeolites. The system sensitivity was evaluated in terms of mass transfer and hydrodynamic parameters using two methodologies. First, the sensitivity factors of input variables were evaluated according to a disturbance of ± 20% in the nominal parameter values; second, the factorial design methodology was employed. In both cases, the responses were obtained by means of model simulations. RESULTS: From the sensitivity analysis by experimental design, the best operational conditions for adsorption of CA on zeolites were solid to liquid percentage 7.0%, initial CA concentration 300 mg L^?1 and particle diameter 0.100 mm, which led to a reduction of 25 min in the adsorption time and 9% in the adsorption capacity, increasing the process productivity. CONCLUSION: The use of the factorial design had advantages compared with the conventional method because it provided information regarding the possibility of simultaneous changes in the factors investigated, enabling analyses of system sensitivity regarding operational parameters, as well as the choice of more suitable parameters. Copyright © 2012 Society of Chemical Industry     

Effect of compressed fluids treatment on the activity,stability and enzymatic reaction performance of β-galactosidase

The present work investigates, as a first step, the influences of pressure, exposure time and depressurisation rate on the β-galactosidase activity of permeabilized cells of Kluyveromyces marxianus CCT 7082 submitted to treatment with compressed carbon dioxide, propane and n-butane. In general, results showed that the enzyme activity changes significantly, depending on the experimental conditions investigated, allowing the selection of proper operating conditions for advantageous application of this biocatalyst in hydrolysis reactions. Further, the stability of the enzyme, after high-pressure pre-treatment, was also experimentally monitored, and the results demonstrated that the activities of this biocatalyst were always higher than those of the non-treated one. Finally, evaluation of synthesis of galactooligosaccharides (GOS), using β-galactosidase without treatment and after treatment in compressed fluids, was carried out. Results indicated promising possibilities since the use of n-butane-pre-treated enzyme led to very satisfactory reaction conversions and selectivity.     

Linear stability analysis of two‐layer rectilinear flow in slot coating

Two‐layer coating occurs in many products. Ideally, the liquids are deposited onto the substrate simultaneously. In the case of two‐layer slot coating, the interlayer between the coating liquids is subjected to enormous shearing. This may lead to flow instabilities that ruin the product. It is important to map the regions of the parameter space at which the flow is unstable. Most of the stability analyses of two‐layer rectilinear flow consider the position of the interlayer as an independent parameter. Classical results cannot be applied directly in coating flows. We present a linear stability analysis of two‐layer rectilinear flow considering the flow rates as an independent parameter. The predicted neutral‐stability curves define the region of stable flow as a function of the operating parameters. The range of coating operating conditions is restricted further, when the condition for the desirable interlayer separation point location are considered together with the stability condition. © 2010 American Institute of Chemical Engineers AIChE J, 2010