An unprecedented rate of construction has profoundly increased the risk of scarcity of natural resources and threatened ecosystem sustainability. To establish an effective sustainable development policy, it is imperative to promote the use of responsible production channels, including waste recycling. Reuse of harbor dredged sediment is commonly investigated as a valuable alternative to non-renewable natural resources needed for construction. Sediment characterization is decisive in the valorization process, aiming to identify potential recycling paths. Existing research efforts, however, have rarely investigated case studies in developing countries. Moreover, they have tended to focus on the technical aspects, ignoring economic feasibility, which carries important implications. This paper fills this gap first by meticulously selecting laboratory tests for characterization within the means available in developing countries and second by conducting a cost-benefit analysis. The port of Safi, Morocco, was chosen for the implementation of the adopted approach. Results showed that dredged sediment is a sand readily reusable as a construction aggregate. Several applications are possible, the most interesting one being concrete works, as a substitute for conventional sand. While treatment by washing and dehydrating proved necessary, cost-benefit analysis confirmed the profitability of recycling. Hence, beneficial reuse of dredged sediment as construction material is technically and economically feasible.

The Barium Titanates are very promising materials ecologically, but still have poor piezoelectric properties compared to the Lead Zirconate Titanates. So in order to improve them, a substitution of the zirconium in our ceramic (BT) has been investigated by X-ray diffraction (XRD) and grain size distribution. After the preparation of the BZT powder in chemical way we have added a sintering aid (Li₂O₃ - Bi₂O₃-CuO) and we have tried to study our massive ceramic. The X-ray diffraction, grain size distribution and scanning electron microscope of the BZT with LBCu show a better particles arrangement and density. In other hand we have noticed an important improvement of the piezoelectric properties (d₃₃ = 220 pC/N at 25°C) especially in comparison with other lead-free ceramics. These properties make BZT a lead-free high performance material for piezoelectric applications.

Vibration-based energy harvesting is a growing field for generating low-power electricity to use in wireless electronic devices. These applications are usually in an environment of abundant low frequency vibration, which can be collected through an appropriate energy conversion structure. However, traditional energy conversion architectures such as cantilever-cantilever type or spring-mass type have the problem of high working frequency and narrow bandwidth (limiting its use and far from the frequency found in the surrounding environment). To overcome these challenges, this work proposes a study of a piezoelectric vibration energy harvester based on a dual cantilever structure. The energy harvesting system is designed, analyzed and verified with the finite element analysis method and an experimental study. The results show that the bandwidth is enlarged of 30 Hz and a power is generated and equals to the sum of the power generated by each cantilever (190 nW) with an output voltage supplying a resistive load of 110 KΏ.

Piezoelectricity and thermoelectricity, as energy harvesting processes, have drawn noteworthy attention for the last decades. They offer a promising alternative for power generation, they are modular and have a great capacity for storage. Nevertheless, they are small-scale conversion techniques producing very low power of a few microwatts. For this reason, harvesting mechanical and thermal energy simultaneously, using piezoelectricity and thermoelectricity effects, seems to be an appropriate process to enhance the power density in the output of the energy harvesting devices. This work proposes to conceive a hybrid multilayer material. It will be based on a sandwich deposition of two flexible materials (PEDOT:PSS:poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)–PU/PZT composite:polyurethane/titanium zirconates of lead) combining interesting properties in recovering both, waste heat and ambient vibration. On the one hand, the rigidity of metal used as common electrodes significantly reduces the performance of the piezoelectric effect. Consequently, these electrodes will be replaced by flexible thermoelectric conductive polymers to enhance the power harvested by the piezoelectricity effect. Moreover, the different properties of the hybrid material will be defined using mixture laws and empirical models for multilayers. On the other hand, an estimation of the power density recovered by both effects will show that the piezoelectric effect overpowers the thermoelectric effect with a percentage exceeding 90%.