Istituto Nazionale di Ricerca Metrologica
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Quantitative analysis and processing of surfaces and profiles from profilometry images
Get PDFSurface metrology is concerned with inspecting morphological parameters of a surfaces or profiles, by using contact or non-contact profilometers. The following abstract describes the development of a software in Python environment that implements various processing methods on images from optical and stylus profilometers. In particular, the program focusses on image pre-processing and determination of dimensional parameters for 2D areas and 1D profiles. It is worth mentioning that many open and closed source programs are already distributed, but they do not provide a sufficient automatization in the image processing, often requiring the user to repeat the same steps for each image to obtain the expected results. The program has been initially developed within the framework of the EMPIR 20IND07 TracOptic project for the processing of a batch of topographies on RS-M and RS-N linear step samples, in order to compensate for the lack of automation for the calculation of height parameters. The developed program is designed to be modular and scalable for expanding the processing capabilities
Hard ferromagnets as a new perspective on materials for thermomagnetic power generation cycles
Get PDFLaser-Induced Fabrication of Micro-Optics on Bioresorbable Calcium Phosphate Glass for Implantable Devices
Get PDFResolving Molecular Size and Homologues with a Self-Assembled Metal–Organic Framework Photonic Crystal Detector
Get PDFTraditional environmental photonic sensing based on the balanced reflection of a photonic structure can hardly be applied to distinguish molecular size and homologues, since the refractive index change introduced by these analytes can be too similar to be unambiguously distinguished. Here, a sensing method based on the pore size selectivity and organics adsorption-desorption capacity of self-assembled ZIF-8 photonics crystal is demonstrated, which can tell apart different molecular sizes, homologues, and organics with similar structures and physical properties. Specificity is improved by the inherent relationships between the pore size of ZIF-8 metal-organic frameworks and the associated molecular diffusion rates in the pores, so that the combination of the observed peak shift and recovery time are unique to each analyte. Using this method, selective detection of molecular size is also demonstrated in the case of linear vs cyclic molecules, since only the former can penetrate inside the ZIF-8 pores to induce a large wavelength shift. The reflection peak shift caused by the linear molecules was found to be about 30-40 nm, an order of magnitude larger compared to those for the cyclic molecules. A relationship between the diffusion rate of linear molecules in ZIF-8 pore and the recovery time of photonic crystal reflective peak is further established, linking the recovery time and the linear molecular diffusion coefficient. Finally, different linear molecules are identified by their associated recovery time to detect homologues or organics with similar refractive inde
An ecological investigation on lichens and other lithobionts colonizing rock art in Valle Camonica (UNESCO WHS n. 94) addresses preventive conservation strategies
Get PDFWettability of soft PLGA surfaces predicted by experimentally augmented atomistic models
Get PDFA challenging topic in surface engineering is predicting the wetting properties of soft interfaces with different liquids. However, a robust computational protocol suitable for predicting wettability with molecular precision is still lacking. In this article, we propose a workflow based on molecular dynamics simulations to predict the wettability of polymer surfaces and test it against the experimental contact angle of several polar and nonpolar liquids, namely water, formamide, toluene, and hexane. The specific case study addressed here focuses on a poly(lactic-co-glycolic acid) (PLGA) flat surface, but the proposed experimental-modeling protocol may have broader fields of application. The structural properties of PLGA slabs have been modeled on the surface roughness determined with microscopy measurements, while the computed surface tensions and contact angles were validated against standardized characterization tests, reaching a discrepancy of less than 3% in the case of water. Overall, this work represents the initial step toward an integrated multiscale framework for predicting the wettability of more complex soft interfaces, which will eventually take into account the effect of surface topology at higher scales and synergically be employed with experimental characterization techniques
Performance of Cs-Doped Carbon-Based Perovskite Solar Cells in Ambient Environment
Get PDFThe development of organometal halide-based perovskite solar cells (PSCs) has made remarkable progress in photovoltaics. The commercialization of PSCs is still significantly limited, owing to their poor stability and the high material cost of a hole transport layer (HTL) and metal electrodes. To counter these issues, a carbon-based HTL and noble metal-free PSCs are being used. In this work, the effect of Cs-doping on perovskite film morphology and device performance has been systematically studied because the Cs+ and Br- ions-doping has proved to be a good choice to improve the stability of PSCs in combination with a carbon electrode. The results showed that when the Cs-doping concentration in perovskite film, MA1-xCsxPb(I1-yBry)3, was equal to x = 0.09, there was a substantial change in the morphological and optoelectronic properties of perovskite films. The grain size of perovskite films was improved from 70 nm (x = 0.00 control) to 170 nm (x = 0.09 Cs-doped), reducing grain boundaries. Moreover, the trap states were additionally passivated resulting in improved radiative recombinations in the perovskite film. The device fabrication was carried out in a controlled dry glovebox, with relative humidity < 40% using carbon as a counter electrode. As a result, Cs-doped PSCs showed a significant increase in efficiency (5.27%) compared to control PSCs (1.55%)
Developmental analysis and optical modelling of short cell phytoliths in Festuca exaltata (Poaceae)
Get PDFShort cells of Poaceae often contain a cell lumen (CL) phytolith. The aim of this investigation was to analyse the features, development and possible function of CL phytoliths in Festuca exaltata leaves. This study employed light microscopy (LM), scanning and transmission electron microscopy (SEM and TEM respectively). The interaction of light with these phytoliths was modeled using the Finite-Difference Frequency Domain (FDFD) method. The results showed that silica deposition begins within a medium electron density matrix. Proteins were detected in the center of the cytoplasm in a higher amount during the young stage. This occurrence suggests that proteins may be a possible component of the matrix or at least play a role in the silica deposition. At maturity, the short cell phytoliths have peculiar morphology and positioning. These were tested numerically to verify their possible role in either conveying or deflecting light rays, showing only a negligible influence of the phytoliths on the distribution of light within the leaf. A channel apparently connects the silica and the cork cell, suggesting that the cork cells have a metabolic activity related to the metabolism of the silica cells, but possibly not exclusively related to the development
Antioxidant and Anti-Inflammatory Effect of Cinnamon (Cinnamomum verum J. Presl) Bark Extract after In Vitro Digestion Simulation
Get PDFCinnamon bark is widely used for its organoleptic features in the food context and growing evidence supports its beneficial effect on human health. The market offers an increasingly wide range of food products and supplements enriched with cinnamon extracts which are eliciting beneficial and health-promoting properties. Specifically, the extract of Cinnamomum spp. is rich in antioxidant, anti-inflammatory and anticancer biomolecules. These include widely reported cinnamic acid and some phenolic compounds, such asproanthocyanidins A and B, and kaempferol. These molecules are sensitive to physical-chemical properties (such as pH and temperature) and biological agents that act during gastric digestion, which could impair molecules' bioactivity. Therefore, in this study, the cinnamon's antioxidant and anti-inflammatory bioactivity after simulated digestion was evaluated by analyzing the chemical profile of the pure extract and digested one, as well as the cellular effect in vitro models, such as Caco2 and intestinal barrier. The results showed that the digestive process reduces the total content of polyphenols, especially tannins, while preserving other bioactive compounds such as cinnamic acid. At the functional level, the digested extract maintains an antioxidant and anti-inflammatory effect at the cellular level
Volume nanogratings inscribed by ultrafast IR laser in alumino-borosilicate glasses
Get PDFSelf-assembled nanogratings, inscribed by femtosecond laser writing in volume, are demonstrated in multicomponent alkali and alkaline earth containing alumino-borosilicate glasses. The laser beam pulse duration, pulse energy, and polarization, were varied to probe the nanogratings existence as a function of laser parameters. Moreover, laser-polarization dependent form birefringence, characteristic of nanogratings, was monitored through retardance measurements using polarized light microscopy. Glass composition was found to drastically impact the formation of nanogratings. For a sodium alumino-borosilicate glass, a maximum retardance of 168 nm (at 800 fs and 1000 nJ) could be measured. The effect of composition is discussed based on SiO2 content, B2O3/Al2O3 ratio, and the Type II processing window is found to decrease as both (Na2O+ CaO)/Al2O3 and B2O3/Al2O3 ratios increase. Finally, an interpretation in the ability to form nanogratings from a glass viscosity viewpoint, and its dependency with respect to the temperature, is demonstrated. This work is brought into comparison with previously published data on commercial glasses, which further indicates the strong link between nanogratings formation, glass chemistry, and viscosity