Effects of pulp and paper mill effluents on the microplankton and microbial self-purification capabilities of the Biobío River, Chile

Most studies focus on the ecotoxicity of pulp and paper mill effluents, rather than on how they affect the physicochemical and biological structure and the intrinsic ecological capabilities of the receiving watercourses. We investigated the impact of such effluents on the water quality, microplankton system and microbial self-purification capacity (degradation of polymeric organic compounds via extracellular enzymes) of the Biobío River in Chile. The physicochemical impact on the water quality was indicated by raised conductivity, by the pollution of the water body with nitrate, nitrite and soluble reactive phosphorus, by the appearance of tannin and lignin, and by the steady accumulation of inorganic and organic suspended matter (SPM) along the river. From the biological structure of the microplankton system, very low and declining concentrations of chlorophyll a and heterotrophic flagellate densities were determined. The pulp and paper mill effluents introduced high bacterial abundances and biomass concentrations into the river water. This reflects the effective use made of the abundantly available inorganic and organic nutrients within this industrial and municipal process water by bacteria adapted to these extreme environments, additionally supported by concomitant low grazing pressure derivable from low heterotrophic flagellate abundances. Indeed, in one section of the river affected by a pulp mill, the plant was found to significantly contribute to the self-cleaning capacity of the river. However, this elevated degradation capacity was not enough to compensate for the additionally discharged organic material which, together with the toxic effects of the paper plant effluents, significantly interferes with the ecological status of the Biobío River.     

Shear Initiation of Al/MoO3‐Based Reactive Materials

Reactive mixtures based on nano aluminium and nano‐ or micron size molybdenum trioxide have been pressed. These energetic mixtures have been tested in the Ballistic Impact Chamber and as an energetic projectile impacting a steel plate. Al/MoO₃‐based reactive mixtures can be initiated by a controlled mechanical stimulus. The sensitivity depends on deformation velocity, pressing density, addition of fluorine containing binder and particle size. Nanometric mixtures of Al and MoO₃ have a shorter time to reaction compared to the corresponding mixtures with micron size MoO₃. The sensitivity decreases with increase in porosity. No influence of fuel/oxidizer ratio has been found in the experiments. An extensive deformation is needed before the start of reaction is observed. An analytical evaluation of shear rate cannot be applied as a detailed numerical simulation of the deformation process in PBXN‐109 shows.     

Applications of spectral computer simulation to surface analysis of materials

This work involves surface analysis by nuclear techniques, which are non-destructive, and computer simulation. The energy analysis method for the nuclear reaction analysis is implemented. Energy spectra are computer simulated and compared to experimental data, giving target composition and concentration profile information. The simulations use, mainly, the target parameterization and the available nuclear data. The method is successfully applied to the determination of uniform concentration profiles of ¹²C, along considerable depths, for a thick target, and for a very thin film. Uniform concentration profiles of ¹⁶O are obtained from (d,p) and (d,α) reactions along large depths. A uniform step concentration profile of ¹⁸O in a thick oxide target is also obtained. Elastic scattering is used in the context of a thin Ag film. SEM proves to be a useful technique for checking surface topography.     

Boron-polymer composites engineered for compression molding,foaming, and additive manufacturing

Boron (specifically ¹⁰B) is the element of choice to shield thermal neutrons due to its large (n, α) cross-section; however, very few polymer composites containing high boron concentrations are available. This study aimed to determine the maximum possible amount of boron that could be introduced into a polymer matrix. Diverse manufacturing techniques, ranging from additive manufacturing to compression molding, were employed to fabricate inks and filaments for 3D printing, foams, and flexible pads. Composites using siloxanes, poly(lactic acid), and acrylonitrile butadiene styrene containing up to 80 wt% boron were sucessufully fabricated. The addition of known plasticizers (polyethylene glycol) and reinforcing agents (carbon nanofibers and fumed silica) helped to overcome fabrication problems such as clogging of the printing nozzle or crumbling of compression molded parts. In addition, the thermal-mechanical properties of these novel boron composites were determined and shown to vary according to boron concentration, presence of additives, and fabrication techniques utilized.     

Characterization of extruded films based on poly (butylene succinate) blends to utilize a partially degraded poly (butylene adipate-co-terephthalate)

Polymer blends can improve material processability and can be used to extrude partially degraded materials, such as expired poly (butylene adipate-co-terephthalate) (PBAT), which cannot be normally extruded. Therefore, in this study, the extrudability of PBAT that has passed its expiration date was restored by blending it with poly (butylene succinate) (PBS). Various polymer blends were extruded and characterized to achieve high-efficiency extrusion. The carbonyl indices in partially degraded PBAT and the corresponding control sample detailed the effects of 98 months of aging on molecular properties. The semicrystalline structure consisted of a mixed ordered arrangement of PBS and PBAT chains dispersed in an amorphous matrix. The microscopic images of the surfaces of the polymer films revealed defects and roughness, followed by an increase in the PBAT concentration in blends. Changes in mechanical properties and water vapor permeability correlated with the PBAT concentration in the blends. To avoid polymer loss, we reported a simple method for using PBAT that has passed its expiration date and cannot be extruded. The results revealed that the polymer films could be used in the packaging industry, especially in food and agricultural sectors.     

Nanomaterials patenting in Brazil: some considerations for the national regulatory framework

Progress on the development of nanotechnology has led to a number of initiatives which serve to normalize activities in this area. Among emerging technologies, nanotechnology is one of the most prominent, and it raises high expectations in a wide range of areas affecting daily life. The risks to human health, the pathways of exposure to nanomaterials, and occupational safety are recent issues which require more attention. The study was performed on nanopatents by collecting, processing and analyzing information extracted from specialized patent databases covering the period from 1991 to 2011, totalling 1,343 patents and representing 36 countries. These patents were classified by the International Patent Classification, using the methodology proposed in a study published by Organization for Economic Co-operation and Development, which resulted in six groups of patents, distributed as follows: nanomaterials (40.3 %), medicine and biotechnology (26.6 %), measurement and production (10 %), electronics (2.7 %), energy and the environment (2.2 %), and optical electronics (1 %). Around 17 % of the patents in question did not fall into the adopted classification. The aim of this paper is to analyze the main trends of patenting related to nanotechnology, its development and environmental implications. An additional goal is to assist policy-makers to adjust the regulatory framework on nanotechnology, and to make recommendations for governments, industry, and national organizations, on creating specific subsidies for regulatory framework in Brazil.     

Microgrid Reference Methodology for Understanding Utility and Customer Interactions in Microgrid Projects

A holistic and systematic approach, based in key concepts of systems thinking, systems of systems and management science, can be employed to completely represent, model and analyze microgrid systems. This proposed Microgrid Reference Methodology can guide electric utilities and industrial customers in cooperating to attain the mutual benefits of microgrid projects.     

VLSI architectures for neural networks

An introduction to neural networks and neural information processing is provided. Neurocomputers are discussed, focusing on how their design exploits the architectural properties of VLSI circuits. General-purpose and special-purpose neurocomputer developments throughout the world are examined. As illustration, and to put European developments in perspective, some of the important projects in the United States and Japan are described. European research is then discussed in greater detail