The technologies of the fourth industrial revolution have impacted and benefited all industrial processes in different sectors; this allows the optimization of resources in organizations and turn, an improvement in their productivity. The adoption and implementation of 4.0 technologies have grown rapidly in some countries; in others, it remains a challenge. This article presents a literature review on the use of 4.0 technologies in industries, aimed at identifying the most used technologies, the impacted sectors, and the benefited productivity indicators. This study was carried out using the Core of Science platform and the PRISMA methodology with the information provided from the Scopus and Web of Science databases. The findings indicate that the most used technologies are the Internet of Things, cloud computing, and big data. On the other hand, manufacturing is the activity of the industrial sector with the most influence on these technologies, followed by the automotive industry. Finally, there is evidence of deficient coverage of the use of 4.0 technologies in Latin American countries and, more significantly, European countries.

La cosecha de energía (energy harvesting, en inglés), se define como el conjunto de estrategias orientadas a capturar energía residual disponible en forma vibracional, eólica, térmica, solar, electromagnética, electrostática, inductiva o piezoeléctrica y convertirla en potencia eléctrica útil para suminístrala a sistemas de bajo consumo [1], [2]. En este campo, la conversión piezoeléctrica ha adquirido relevancia por su alta densidad de potencia, ausencia de interferencia electromagnética, facilidad de miniaturización y compatibilidad con sensores, MEMS y nodos inalámbricos [3], [4], [5]. Dentro de las configuraciones estructurales más estudiadas, se encuentran las vigas en voladizo con parches piezoeléctricos que concentran esfuerzos cerca del empotramiento, lo cual favorece la conversión electromecánica [5], [6]. Los tipos de piezoeléctricos más usados son: zirconato titanato de plomo (PZT), fluoruro de polivinilideno (PVDF) y compuesto de macrofibras piezoeléctricas MFC, seleccionados de acuerdo con su grado de rigidez, acoplamiento electromecánico, flexibilidad, biocompatibilidad y tamaño [3], [4].

Vibration-based piezoelectric energy harvesting provides a potential power source for low-consumption devices; however, its prediction requires a consistent representation of localized structural properties and experimentally identified modal behavior. This study presents the structural and modal qualification of an analytical electromechanical model for a 6061-T6 aluminum cantilever beam carrying a finite one-sided PZT-5J piezoelectric patch, with unequal beam and patch widths, under base excitation. The specific contribution is the traceable integration of local neutral-axis relocation, spatially varying mass and flexural rigidity, a finite-patch indicator function, $d_{31}$ electromechanical coupling, multimodal projection, and mode-specific reduced-order equations. Two beam lengths, $275$ and $250 \mathrm{m}\mathrm{m}$, were investigated using broadband shaker excitation, accelerometry, and scanning laser vibrometry. The measured first and second bending frequencies were $16.56$ and $110.31 \mathrm{H}\mathrm{z}$ for the $275 \mathrm{m}\mathrm{m}$ beam and $19.14$ and $125.00 \mathrm{H}\mathrm{z}$ for the $250 \mathrm{m}\mathrm{m}$ beam. Experimental damping ratios obtained from the frequency-response functions ranged from $6.54\times {10}^{-3}$ to $1.55\times {10}^{-2}$. The analytical formulation reproduced the increase in modal frequencies produced by reducing the beam length and captured the measured transverse mode-shape trends. Experimentally identified frequencies, base accelerations, and damping ratios were subsequently introduced into the reduced model to obtain experimentally parameterized model outputs. The largest calculated peak voltage and estimated average electrical power were $155.99 \mathrm{m}\mathrm{V}$ and $1.22 \mathsf{\mu }\mathrm{W}$, respectively, for the first mode of the $275 \mathrm{m}\mathrm{m}$ beam across a reference $10 \mathrm{k}\mathsf{\Omega }$ resistive load. The reported qualification is restricted to the structural and modal response of the two tested configurations; the electrical quantities are calculated outputs rather than independent electrical measurements.