Recycling and reuse of waste from electricity distribution networks as reinforcement agents in polymeric composites

Of the waste generated from electricity distribution networks, wooden posts treated with chromated copper arsenate (CCA) and ceramic insulators make up the majority of the materials for which no effective recycling scheme has been developed. This study aims to recycle and reuse this waste as reinforcement elements in polymer composites and hybrid composites, promoting an ecologically and economically viable alternative for the disposal of this waste. The CCA wooden posts were cut, crushed and recycled via acid leaching using 0.2 and 0.4 N H₂SO₄ in triplicate at 70 °C and then washed and dried. The ceramic insulators were fragmented in a hydraulic press and separated by particle size using a vibrating sieve. The composites were mixed in a twin-screw extruder and injected into the test specimens, which were subjected to physical, mechanical, thermal and morphological characterization. The results indicate that the acid treatment most effective for removing heavy metals in the wood utilizes 0.4 N H₂SO₄. However, the composites made from wood treated with 0.2 N H₂SO₄ exhibited the highest mechanical properties of the composites, whereas the use of a ceramic insulator produces composites with better thermal stability and impact strength. This study is part of the research and development project of ANEEL (Agência Nacional de Energia Elétrica) and funded by CPFL (Companhia Paulista de Força e Luz).     

Influence of pore size of plankton nets and towing speed on the sampling performance of two high-speed samplers (Delfino I and II) and its consequences for the assessment of plankton populations

The sampling performance of two high-speed samplers, (Delfino I and II), fitted with a calibrated flow meter, was studied in the open Ligurian Sea using a battery comprising 6 such Delfinos linked together. Since, in plankton counts, only those organisms should be counted which are definitely retained in the nets, several techniques for the separation of the organisms which pass through the pore of a net of a given pore size and those which are safely retained were tested. Attempts to separate these two fractions by filtration of the fixed sample through nets of different pore sizes were not successful, as living organisms were able to pass through pore sizes which retained dead organisms. However, optical sizing under the dissecting microscope during counting gave reproducible results. Using this counting technique, the influence of the pore size of plankton nets on the reproducibility of sampling of natural populations was studied. The results obtained show that live plankton passes through the net pores at a size at which fixed plankton is retained. Hence, the minimum retention size for living and dead plankton is different. By comparing samples taken with nets of different pore sizes, and counting the organisms caught according to different sizes, it was possible to determine the minimum retention size of live plankton organisms for several different net pore-sizes. The minimum retention size is, therefore, the smallest pore size at which the organisms of a certain width cannot escape through the pores of the net and are, thus, quantitatively retained in the net. By applying the criterion of minimum retention size, the influence of speed towing on the number of plankton organisms caught was studied. It was shown that the number of organisms which are safely retained, i.e., do not escape through the pores, increased with speed, reaching a plateau at 5 to 7 knots.A contribution under the Association Contract CNEN-EURATOM. Contribution No. 668 of the Euratom Biology Division.     

A sampler for the aseptic collection of water samples in the sea

A sampler is described which can be used for the collection of microbiological, phytoplanktological, and chemical sea-water samples. The sampler consist of a polyvinylchloride (PVC) frame on which a sterile silicone-rubber container (500 ml) is assembled. The sampler is fitted with a couple of reversing thermometers. All materials used, including the hydrographic cable and the messenger, have been tested for toxicity. The container, actuated by the messenger, fills and then is closed by a stop-cock to prevent any contamination with upper-level sea water during hauling aboard. The reversing thermometers reverse only when the sample has been taken properly. Thus, the thermometers guarantee good functioning of the sampler and supply also information on the exact depth at which the sample was collected. The device can operate at any depth and several devices can be operated in one cast. During normal operation, contamination due to microorganisms attached to the frame and container is negligible.This work was performed under the association contract Euratom-CNEN.     

Characterization of composites based on expanded polystyrene wastes and wood flour

This paper aims to evaluate the potential for the use of recycled expanded polystyrene and wood flour as materials for the development of wood plastic composites. The effects of wood flour loading and coupling agent addition on the mechanical properties and morphology of wood thermoplastic composites were examined. In addition, a methodology for the thermo-mechanical recycling of expanded polystyrene waste was developed. The results show that the mechanical properties decreased as the wood flour loading increased. On the other hand, the use of poly(styrene-co-maleic anhydride), SMA, as a coupling agent improved the compatibility between the wood flour and polystyrene matrix and the mechanical properties subsequently improved. A morphological study revealed the positive effect of the coupling agent on the interfacial bonding. The density values obtained for the composites were compared with the theoretical values and showed agreement with the rule of mixtures. Based on the findings of this work, it appears that both recycled materials can be used to manufacture composites with high mechanical properties and low density.     

Development of composites using residue from laminated packaging with discarded foundry sand

Journal of Material Cycles and Waste Management - In recent years, the use of residue for the production of new composite materials has gained prominence as it enables reuse of materials and...