This work aimed to investigate and compare the composition and the physicochemical properties of 18 different sources of edible vegetable oils. A systematic study on the correlation between ...composition and physical properties was performed using Fourier Transform Infrared (FTIR) Spectroscopy and fatty acid chromatographic analysis. Principal component analysis of FTIR spectra is performed to classify edible oils concerning their physical properties. The results demonstrate the potentiality of the method associated with multivariate statistics analysis as powerful, fast, and non-destructive tools for characterization and quality control of edible vegetable oils.
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•The correlation of composition and physicochemical properties of edible vegetable oils•Chromatographic and spectroscopic techniques associated with multivariate statistics analysis•Unsaturated fatty acids are related to mass density, dynamic viscosity, oxidative stability index and refractive index.•These techniques allow predicting oil properties, helping in the characterization and quality control of vegetable oils.•Direct correlation of the PCA components with the set of information about composition and physical properties of the oils
•Tellurite–tungstate fiber glasses doped with Pr3+ and Pr3+/Yb3+ were produced.•Broadband emission at 1480nm is observed under 474nm pumping.•Pumping at 980nm an intense emission at 1330nm is ...observed in the codoped sample.•Rare-earth based NIR ultra-broadband emission is demonstrated.
A study of the broadband near-infrared emission in Pr3+ single doped and Pr3+/Yb3+ codoped tellurite–tungstate glasses for optical amplification is presented. In the Pr3+ single doped samples pumped at 474nm the emission band at 1480nm presents a FWHM of ∼140nm. The Yb3+ addition produces a FWHM broadening up to ∼155nm, achieved through the 1G4–3H5 transition. The emission spectra when the codoped sample is pumped at 980nm shows efficient energy transfer from Yb3+ to Pr3+, resulting in an intense Pr3+ emission around 1330nm. This shows that changing the pump wavelength it is possible to select the 1D2–1G4 or the 1G4–3H5 transition, displacing the emission band from ∼1480 to ∼1330nm.
Laser-induced wavefront distortion is detectable by several techniques based on the photothermal effect. The effect is probed by monitoring the phase shift caused by the bulging of the heated area, ...the photoelastic effects, and the spatial distribution of the refractive index within the sample and in the fluid surrounding it. A simple analytical solution for the wavefront distortion was only possible for low absorbing materials, with the assumption that the stresses obey either the thin-disk or the long-rod type distributions. Recently, a unified theoretical description for the laser-induced optical path change was proposed to overcome part of this limitation for weakly absorbing materials, regardless of its thickness. In this work, we perform an experimental investigation taking the sample–fluid heat coupling effect into account using the thermal lens technique. The experimental investigation presented here validates the unified model. In addition, we show that the heat-coupling model provides an alternative method to obtain physical properties of non-absorbing fluid by using a reference solid sample.
The international public health emergency related to COVID‐19 caused by the SARS‐CoV‐2 virus has altered several production and registration criteria for sanitary products, including alcohol‐based ...hand sanitizers. In this work, we investigate the concentration of alcohol in sanitizers presented in gel form applying the principal component regression method on measurements using Infrared and Raman spectroscopic methods. The chemometric calibration is performed using isopropanol or ethanol as active agents, and the method is used to characterize several commercial samples. Furthermore, the results of the prediction of alcohol concentration, obtained by applying the principal component regression and partial least squares methods, in the spectroscopic techniques, were compared with each other and with the results provided by nuclear magnetic resonance. Our results show that spectroscopic techniques coupled with principal component regression are fast, low‐cost, and safe tools for the determination of alcohol concentration, regardless the gelling agent used.
The association between chemometrics and spectroscopy in the determination of alcohol in sanitizing products in the form of a gel allows for a quick, low‐cost measurement without subjective treatment of the spectroscopic analysis results.
Fundamental studies of light-matter interactions are important for basic knowledge and in applications. Thanks to advances in experimental and theoretical methods, nowadays it is possible to perform ...such studies in a broad dynamic range, covering timescales from that of elementary interactions to real time. In the present work, we perform an experimental-theoretical study of light intensity-dependent femtosecond and CW-laser induced frequency upconversion in hierarchically structured core-multishell nanoparticles co-doped with NdIII, YbIII, and ErIII. Upconversion spectra recorded with CW and femtosecond excitation are qualitatively similar whereas the intensity dependence of upconversion depends on excitation mode (CW or femtosecond). To further assess the observed intensity dependence, we perform light-matter interaction simulations in the dynamic range from 100 fs to 3 ms for 18-level system describing the UCNPs, including nine levels of the NdIII, two of the YbIII, and seven of the ErIII ions and a classical model for the excitation source. The calculated time- and intensity-dependent energy level population are compared with measured spectra to understand CW vs femtosecond laser-induced upconversion. To further discuss the differences between CW and femtosecond laser-induced light-matter interactions for the systems studied here, we perform semi-classical pulse propagation simulations and ultrafast pump-probe measurements to study how the light source bandwidth, relative to the absorption linewidth, influence light absorption and transmission and further connect these results with the intensity dependence. Overall, we report our progress toward mechanistic studies of light-matter interaction and photophysical pathways following femtosecond excitation and UCNPs.
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•Core@shell UCNP upconversion was investigated with CW and femtosecond laser.•For same average power, different upconversion mechanism with CW vs. femtosecond.•18-level system modeling of NdIIIYbIIIErIII to understand experimental results.•CW/femtosecond power-dependent upconversion can be treated on the same footing.•Excitation bandwidth of CW/femtosecond source also affects UCNP photophysics.
In this paper, it is proposed and numerically tested a 4 −THz guard-band-less integrated all-optical wavelength converter (iAOWC) with two four-wave mixing (FWM) stages. The nonlinear media used in ...each stage is a waveguide with a tellurite core that is buried into a SiO2 substrate. The core is shaped as two interleaved spirals connected in their centers by two arcs of a circle to minimize bend loss. The iAOWC can continuously shift a 4 −THz WDM bandwidth from the C- to the L-band and vice versa. In the physical layer simulations, 80×28−GBaud, as DP-QPSK and DP-16QAM, 50-GHz-WDM signals were propagated, respectively, through typical distances found in ultra-long-haul and long-haul transmission systems. For up to four wavelength conversions, the penalties imposed on the signals bit-error-ratios by the iAOWCs were negligible. In the network layer simulations, blocking probabilities were estimated in the CORONET and PANEUR topologies supposing an incremental traffic scenario. Physical layer results were fundamental for the parameters (route lengths, wideband conversion, and spectral shift) considered in the network layer analysis. All network links could carry up to 160 wavelengths that extended from C- to L-band. It is shown that by using an iAOWC with bandwidth of 4-THz instead of 1-THz, both with the same spectral shift capability, to match the blocking probabilities achieved with OEOWCs, this would lead to a reduction of 50% and 40% in the number of required devices for the CORONET and PANEUR topologies, respectively. Finally, this is the first time that it is reported a joint analysis of the physical and network layers regarding the impact of wideband wavelength conversion on the performance of optical networks, specially using an integrated all-optical device and under real-world traffic scenarios.
•A wideband integrated all-optical wavelength converter was numerically tested.•Wavelength converter can operate with dual-polarization WDM signals.•Wavelength converter imposes negligible penalty on the WDM signals BER.•Physical and network layers analysis on the impact of wavelength conversion.•The wider the wavelength converter band, the fewer the required devices.
We propose improvements to a time-resolved gas volume meter based on bubble count. This type of sensor is dedicated to small-scale laboratory applications, usually related to gas production in ...biological processes. We highlight the cost reduction and simplification in the manufacturing method of this type of sensor, when compared to the manufacturing method. To achieve this purpose, the sensor’s glass body was replaced by plastic material, a detection system based on the detection of capacitance variation was introduced and without contact with the measuring fluid, the data acquisition system was built based on small single-board computer and a graphical user interface were developed in an open source programming language. Theses innovations are significant for scientific research institutions, with limited financial resources, to uses gas volume sensors that can be applied in the investigation of biological processes such as alcoholic fermentation, biogas and biohydrogen generation.
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•Improvements in the gas volume measurement based on bubble counting.•Simplification of the sensor construction method by replacing glass with plastic material.•Detection system without contact with the gas and free from the action of oxidation and external interference.•Time-resolved determination of gas volume in anaerobic biological processes.
A study of the broadband near-infrared emission in Pr super(3+) single doped and Pr super(3+)/Yb super(3+) codoped tellurite-tungstate glasses for optical amplification is presented. In the Pr ...super(3+) single doped samples pumped at 474 nm the emission band at 1480 nm presents a FWHM of similar to 140 nm. The Yb super(3+) addition produces a FWHM broadening up to similar to 155 nm, achieved through the super(1)G sub(4)- super(3)H sub(5) transition. The emission spectra when the codoped sample is pumped at 980 nm shows efficient energy transfer from Yb super(3+) to Pr super(3+), resulting in an intense Pr super(3+) emission around 1330 nm. This shows that changing the pump wavelength it is possible to select the super(1)D sub(2)- super(1)G sub(4) or the super(1)G sub(4)- super(3)H sub(5) transition, displacing the emission band from similar to 1480 to similar to 1330 nm.
