Zinc oxide in nanometric dimensions, thanks to its optical properties, is an oxide of great interest for its potential use as a revealing agent for latent fingerprints. In this article we present the synthesis and characterization of ZnO nanoparticles obtained by two methods and it uses in revealing of latent fingerprints on non-porous surfaces. The nanoparticles synthetized present an atomic Zn:O ratio of 0.99 and 1.15 when precipitation and combustion in solution method were used, respectively. Both samples show a hexagonal arrangement (wurtzite) according to the X-ray diffraction and Raman spectra. Raman results show a shift at 439 cm−1 corresponding to the E2 (high) mode of the ZnO crystalline hexagonal wurtzite structure. Transmission electron microscopy images show that nanoparticles with smaller average diameters are obtained by chemical precipitation (17.2 ± 10.8 nm) than ...

This research was funded by FONDECYT (National Fund for Scientific, Technological Development and Technological Innovation) under the agreement 147-2017. The author M Mejia has been supported by the CONCYTEC Peru (National Council for Science, Technology and Technological Innovation) doctoral scholarship under the Contract Number 236-2015-FONDECYT as well as by the PUCP vicechancellorship for research (VRI, Project No. CAP-2019-3-0041/702). The authors would like to thank the Katholischer Akademischer Auslander-Dienst institution (KAAD) for the short-term grants given to conduct research internships in the Technische Universitat Ilmenau (TU Ilmenau). Finally, the authors would like to thank the German Research Foundation (DFG) (DFG-Gz: INST 273/56-1 FUGG) and the Materials Characterization Center (CAM) at PUCP, for the financial support to conduct the characterization experiments.

The nominal power of a photovoltaic system is a useful parameter in the determination of the current state of a photovoltaic generator. In the present work, the procedure proposed by Martínez-Moreno was followed, which is based on the Osterwald model. During the application of the procedure, a hysteresis effect was observed to a different extent throughout the experimental campaign. The corrected power versus irradiance values differed during the day, even when the irradiance and temperature of the module were similar. This led to an uncertainty in the inclusion of all the data. Therefore, the addition of a filter of the data is sought in the procedure of the estimation of the nominal power, as a complement to that proposed by Martinez-Moreno in an attempt to clarify the calculation in generators that presents this non-linear behavior.

The nominal power of a photovoltaic system is a useful parameter in the determination of the current state of a photovoltaic generator. In the present work, the procedure proposed by Martínez-Moreno was followed, which is based on the Osterwald model. During the application of the procedure, a hysteresis effect was observed to a different extent throughout the experimental campaign. The corrected power versus irradiance values differed during the day, even when the irradiance and temperature of the module were similar. This led to an uncertainty in the inclusion of all the data. Therefore, the addition of a filter of the data is sought in the procedure of the estimation of the nominal power, as a complement to that proposed by Martinez-Moreno in an attempt to clarify the calculation in generators that presents this non-linear behavior.

The amount of dust deposited on the surface of a panel depends on the environmental parameters. These are random (eg. humidity, wind speed and ambient temperature) which makes it difficult to model them theoretically. This paper describes the effect of dust by calculating the derating factor (η_polvo) and modeling its dependence over time. To achieve this, an experimental campaign was carried out in three tandem (a-Si / µc-Si) of 1.15 kW controlled in the city of Lima, divided into two periods of time. In the first period, from 07.15.2016 to 04.07.2017, the three strings were cleaned twice per week. The nominal power was calculated for days with clear skies conditions. It was found that between each string there are slight differences or mismatches in the nominal power, which is considered to estimate a correction factor (k) in order to readjust the output power. In the second stage fr...

The amount of dust deposited on the surface of a panel depends on the environmental parameters. These are random (eg. humidity, wind speed and ambient temperature) which makes it difficult to model them theoretically. This paper describes the effect of dust by calculating the derating factor (η_polvo) and modeling its dependence over time. To achieve this, an experimental campaign was carried out in three tandem (a-Si / µc-Si) of 1.15 kW controlled in the city of Lima, divided into two periods of time. In the first period, from 07.15.2016 to 04.07.2017, the three strings were cleaned twice per week. The nominal power was calculated for days with clear skies conditions. It was found that between each string there are slight differences or mismatches in the nominal power, which is considered to estimate a correction factor (k) in order to readjust the output power. In the second stage fr...