Artículos SCI
2023
2023
Materiales Ópticos Multifuncionales
Modeling Weakly Scattering Random Media: A Tool to Resolve the Internal Structure of Nanoporous Materials
Jimenez-Solano, A; Miranda-Munoz, JM; Carretero-Palacios, S; Miguez, HAdvanced Photonics Research, 4 (2023) 5
Show abstract ▽
Nanoporous media scatter a small fraction of the light propagating through them, even if pore sizes are significantly smaller than the characteristic visible wavelengths. The disordered spatial modulation of the refractive index at the few or few tens of nanometers length scale, resulting from the presence of randomly distributed air bubbles or solid aggregates within a continuous solid background, gives rise to these weak scattering effects. However, standard theoretical approaches to describe this kind of media use effective medium approximations that do not account for diffuse, ballistic, and specular components. Herein, all spectral components and the angular distribution of the scattered light are captured through optical modeling. A Monte Carlo approach, combining scattering Mie theory and Fresnel equations, implemented within a genetic algorithm, allows us to decode the void and aggregate size distribution and hence the internal structure of a nanocrystalline titania (TiO2) film chosen as a paradigmatic example. The approach allows to generically describe the scattering properties of nanoporous materials which, as shown herein, may be used to decipher their internal structure from the fitting of their far-optical field properties.
Mayo, 2023 | DOI: 10.1002/adpr.202200267
Nanotecnología en Superficies y Plasma
Optical monitoring of detergent pollutants in greywater
Lahoz, F; de Armas-Rillo, S; Hernandez-Rodriguez, C; Gil-Rostra, J; Yubero, FOptics Express, 31 (2023) 15227-15238
Show abstract ▽
Large amount of wastewater is produced by washing machines and dishwashers, which are used in a daily basis. This domestic wastewater generated in households or office buildings (also called greywater) is drained directly to the drainpipes without differentiation from that with fecal contamination from toilets. Detergents are arguably the pollutants most frequently found in greywater from home appliances. Their concentrations vary in the successive stages in a wash cycle, which could be taken into account in a rational design of home appliances wastewater management. Analytical chemistry procedures are commonly used to determine the pollutant content in wastewater. They require collecting samples and their transport to properly equipped laboratories, which hampers real time wastewater management. In this paper, optofluidic devices based on planar Fabry-Perot microresonators operating in transmission mode in the visible and near infrared spectral ranges have been studied to determine the concentration of five brands of soap dissolved in water. It is found that the spectral positions of the optical resonances redshift when the soap concentration increases in the corresponding solutions. Experimental calibration curves of the optofluidic device were used to determine the soap concentration of wastewater from the successive stages of a washing machine wash cycle either loaded with garments or unloaded. Interestingly, the analysis of the optical sensor indicated that the greywater from the last water discharge of the wash cycle could be reused for gardening or agriculture. The integration of this kind of microfluidic devices into the home appliances design could lead to reduce our hydric environmental impact.
Mayo, 2023 | DOI: 10.1364/OE.466194
Química de Superficies y Catálisis
Carbon Capture Enhancement by Water-Based Nanofluids in a Hollow Fiber Membrane Contactor
Yuan, CT; Pan, Z; Wang, Y; Baena-Moreno, FM; Constantinou, A; Zhang, ZEnergy Technology, 11 (2023) 2300254
Show abstract ▽
Nanoparticles are being used in the CO2 solvents to improve the capture performance. Herein, a 2D model is proposed to study the CO2 capture performance from a gaseous mixture using a hollow fiber membrane contactor (HFMC). Both water-based nanofluids of carbon nanotubes (CNT) and SiO2 are deployed as the carbon absorbents. It is verified that Brownian motion and grazing effect are the major reasons to enhance the mass transfer of nanofluids. The simulation findings show that the modeling data conform well with the experimental studies. The root-mean-square errors for SiO2 nanofluid and CNT nanofluid are 2.37% and 2.56%, respectively. When the amounts of nanoparticles increase between 0.02 and 0.06 wt%, CO2 capture efficiencies of SiO2 and CNT nanofluids increase by 7.92% and 13.17%, respectively. Also, the CNT nanofluid has a better capture performance than the SiO2 nanofluid. Furthermore, research is conducted into how membrane characteristics affect HFMC performance. It is indicated that increasing the membrane porosity and decreasing the membrane tortuosity have a positive impact on the capture efficiency. This work demonstrates the potentials in the use of nanoparticles in CO2 solvents and provides a solid theoretical basis for nanofluids to significantly enhance gas absorption.
Mayo, 2023 | DOI: 10.1002/ente.202300254
Química de Superficies y Catálisis
The Need for Flexible Chemical Synthesis and How Dual-Function Materials Can Pave the Way
Merkouri, LP; Paksoy, AI; Reina, TR; Duyar, MSACS Catalysis, 13 (2023) 7230-7242
Show abstract ▽
![](https://icms.us-csic.es/sites/icms.us-csic.es/files/images_large_cs3c00880_0006.png)
Since climate change keeps escalating, it is imperativethat theincreasing CO2 emissions be combated. Over recent years,research efforts have been aiming for the design and optimizationof materials for CO2 capture and conversion to enable acircular economy. The uncertainties in the energy sector and the variationsin supply and demand place an additional burden on the commercializationand implementation of these carbon capture and utilization technologies.Therefore, the scientific community needs to think out of the boxif it is to find solutions to mitigate the effects of climate change.Flexible chemical synthesis can pave the way for tackling market uncertainties.The materials for flexible chemical synthesis function under a dynamicoperation, and thus, they need to be studied as such. Dual-functionmaterials are an emerging group of dynamic catalytic materials thatintegrate the CO2 capture and conversion steps. Hence,they can be used to allow some flexibility in the production of chemicalsas a response to the changing energy sector. This Perspective highlightsthe necessity of flexible chemical synthesis by focusing on understandingthe catalytic characteristics under a dynamic operation and by discussingthe requirements for the optimization of materials at the nanoscale.
Mayo, 2023 | DOI: 10.1021/acscatal.3c00880
Reactividad de Sólidos
Influence of AC fields and electrical conduction mechanisms on the flash-onset temperature: Electronic (BiFeO3) vs. ionic conductors (8YSZ)
Molina-Molina, S; Perejón, A; Pérez-Maqueda, LA; Sánchez-Jiménez, PECeramics International, 49 (2023) 14834-14843
Show abstract ▽
This work aims to clarify the influence of AC (up to 50 kHz) vs DC fields on the flash-onset temperature, emphasizing the role of the electrical conduction mechanism. BiFeO3 (BFO) is used as an example of electronic conductor while 8-mol % Yttria-stabilized zirconia (8YSZ) is used as an example of ionic conductor. For 8YSZ, a frequency dependence of the flash-onset temperature and flash-induced heating is observed. This is consistent with the different contributions found in the total electrical response of 8YSZ as characterized by impedance spectroscopy measurements. Estimations based on the blackbody radiation model suggest that 8YSZ samples attain higher temperatures under AC fields due to a more efficient heating. Moreover, a noticeable decrease in the activation energy for the electrical conduction after the flash is triggered is attributed to electronic conduction. Meanwhile, the lack of frequency response and insensitiveness to the type of electrical field found in the case of BFO can be attributed to its mainly electronic bulk conduction.
Mayo, 2023 | DOI: 10.1016/j.ceramint.2022.06.242
- ‹ anterior
- 32 of 420
- siguiente ›