In the present work, the synthesis, by means of the sol–gel method, of calcium-deficient hydroxyapatite and Tb-doped calcium-deficient hydroxyapatite with dopant content of 10 and 12 wt% is reported. ...The synthesized samples exhibit diffraction patterns and structural characteristics consistent with those reported in the literature for synthetic hydroxyapatite. The results of the chemical characterization show that the synthesized samples are suitable for biomedical applications, and the incorporation of Tb
3+
in the host structure occurs both substitutional and by dopant insertion in calcium vacancy sites. In addition, using spectroscopic techniques, the values of the valence band, optical band gap energies, and luminescent response were determined for all samples, concluding that the increase in dopant has the consequence of decreasing the value of the optical band gap, as it was expected; However, it is also observed that the maximum luminescent emission is obtained for the sample synthesized with 10 wt% of terbium.
Cocoa cultivation is of considerable economic and social importance to the Amazonas region and is commonly associated with forest species in the region. However, the diversification level and ...composition of cacao agroforestry systems in Peru are poorly understood. The objective of this study is, therefore, to describe the diversity of tree species in cocoa AFS by plantation age. Accordingly, the number of species of 15 plots covering a total of 1.5 hectares was recorded. Moderately low levels of tree species diversity were reported (H' ranged 0.89-1.45). In total 17 species were reported throughout the study area. The most abundant botanical family was represented by a single Musa sp. species. The dissimilarity indices show a moderate similarity between the age ranges evaluated (over 62%). Additionally, the IVI indicates that the most important species are used for food and timber apart from providing shade, additionally major of this species are introduced intentionally for the farmers. Based on the observations, it may be concluded that the farmer's interest in obtaining further benefits from the plot, mostly economic benefits affect the diversification of cocoa agroforestry systems.
to analyse the reliability of 6 age intervals of Spanish web‐based Ages and Stages Questionnaires Third Edition (WB‐ASQ‐3) and parents' acceptability, in a clinical practice context, during COVID‐19 ...pandemic and lockdown in Chile. Cross‐sectional study with a longitudinal component. Internal consistency was analysed by Cronbach's alpha and Pearson product–moment correlation, Pearson's correlations between intervals questionnaires were analysed. Acceptability was determined using a parental satisfaction survey. 1061 children completed 2318 validated questionnaires. Scores were compared with normative sample, except for Gross motor at 8 and 12 months, and Communication at 12, 18 and 24 months, without differences to the previous Chileans sample. In domain analysis, Cronbach's alpha ranged from 0.36 to 0.80 and reached 0.74 to 0.81 for the overall test. Strong positive correlation between the domain and overall score was obtained. Correlation between most questionnaires at different ages was positive and significant. Parental surveys show high satisfaction; parents were thankful for being able to monitor children's development. WB‐ASQ‐3 is a reliable and feasible screening system, particularly when the test is taken as a whole, rather than by domains. It is remarkably high acceptability among parents, especially in complex times such as the lockdown and the COVID‐19 pandemic.
The present study aims to evidence the effect of the excitation line on the planar laser-induced fluorescence of hydroxyl radical (OH-PLIF) imaging in H2-fueled detonation wave. We experimentally ...validated an updated laser-induced fluorescence (LIF) model, called KAT-LIF, which simulates spectrally-resolved fluorescence spectra, using a recently developed optical detonation duct. We numerically investigated the effects of the excitation line, the initial pressure (20–100 kPa), and the diluent (N2/Ar) on the fluorescence spectrum, the spectrally- and one-dimensionally-averaged LIF intensity, and the quantitative capabilities of the OH-LIF measurements for different 2H2-O2-3.76diluent detonable mixtures. The investigated excitation lines were (0,0)Q1(7), both (1,0)Q2(8) and (1,0)Q1(9), and (1,0)Q1(6), which all belong to the A2Σ+←X2Π transition. The main findings are the following: (i) considering the commercially available OH filters, Q2(8)+Q1(9) excitation scheme has the highest LIF intensity for all the investigated H2-fueled detonations, while Q1(7) could provide the strongest intensity with better (custom) collection optics; (ii) the maximum LIF intensity decreases with increasing pressure for all the excitation schemes; (iii) using a single point calibration, at the fluorescence peak, it is not possible to perform quantitative measurements of OH radicals for any H2-fueled detonation, using the conventional excitation schemes. Finally, we experimentally evidenced more favorable excitation schemes to obtain qualitative information far behind the front, by employing the saturated regime of fluorescence or the optically thin linear regime with appropriate laser configuration. These two excitation schemes correspond to more appropriate LIF strategies that will enable better detonation flow visualization in future studies.
Aims. One of the main scientific drivers for ESPRESSO, Échelle SPectrograph, is the detection and characterization of Earth-class exoplanets. With this goal in mind, the ESPRESSO guaranteed time ...observations (GTO) Catalog identifies the best target stars for a blind search for the radial velocity (RV) signals caused by Earth-class exoplanets. Methods. Using the most complete stellar catalogs available, we screened for the most suitable G, K, and M dwarf stars for the detection of Earth-class exoplanets with ESPRESSO. For most of the stars, we then gathered high-resolution spectra from new observations or from archival data. We used these spectra to spectroscopically investigate the existence of any stellar binaries, both bound or background stars. We derived the activity level using chromospheric activity indexes using log (R′HK) $(R' _{\textrm{HK}})$ (RHK′) , as well as the projected rotational velocity v sin i. For the cases where planet companions are already known, we also looked at the possibility that additional planets may exist in the host’s habitable zone using dynamical arguments. Results. We estimated the spectroscopic contamination level, v sin i, activity, stellar parameters and chemical abundances for 249 of the most promising targets. Using these data, we selected 45 stars that match our criteria for detectability of a planet like Earth. The stars presented and discussed in this paper constitute the ESPRESSO GTO catalog for the RV blind search for Earth-class planets. They can also be used for any other work requiring a detailed spectroscopic characterization of stars in the solar neighborhood.
Despite the extensive development of microalgae biotechnology, it still requires new methodologies to lower production costs, especially in the field of biofuel production. Therefore, innovative ...methods that facilitate operations and enable cost-effective production are important in driving this industry. In this study, we propose a new low-cost and easy-to-use procedure, addressed to the generation of a culture medium for Scenedesmus acutus. The medium was obtained by thermal reduction of a sludge sample from El Ferrol Bay (Chimbote, Peru), whereby we obtained an aqueous medium. Our results indicated that the aqueous medium incorporates all necessary nutrients for microalgae production; allowing a maximum biomass of 0.75 ± 0.07 g/L with 60% of the medium; while high lipids production (59.42 ± 6.16%) was achieved with 20%. Besides, we quantified, in the experimental medium and at the end of the cultures, the levels of inorganic nutrients such as ammonium, nitrites, nitrates, and phosphates; in addition to COD and TOC, which were significantly reduced (
0.05) after 7 days of culture, mainly in the treatment with 20%. These results suggest tremendous potential for sludge reuse, which also entails a cost reduction in microalgae biomass production, with additional positive impacts on large-scale application over highly polluted environments.
High-performance nano-optical elements for application wavelengths in the ultraviolet spectral range often require feature sizes of only a few tens of nanometers where line edge roughness (LER) ...becomes a critical parameter for the optical performance. In this contribution, we explore the influence of LER on the optical performance of wire grid polarizers (WGP) in the far ultraviolet range. Therefore, we present a method, which uses the finite difference time domain method in combination with a comprehensive spatial frequency dependent LER model. The measured LER of 3.6 nm (standard deviation) reduces the WGP's extinction ratio by a factor of 3.6 at a wavelength of 248 nm. We identify a critical range of the correlation length, which maximizes the detrimental effect of LER. The presented method and the results provide the basis for future fabrication technology optimization of WGPs and other optical meta-surfaces in the ultraviolet spectral region or at even shorter wavelengths.
•Coke oven (COG), Linz-Donawitz (LDG) and blast furnace (BFG) gases were evaluated.•Heat losses were estimated for COG/LDG and COG/BFG mixtures in a reheating furnace.•Heat of exhaust gases was ...recovered to preheat the load and the combustion air.•Fuel consumption was reduced by 18.9% and 21.1% for each preheating.•Furnace efficiency was increased by 23.3% and 15.2%, respectively.
The reheating furnace of the steel industry was evaluated in the present study, which uses the gas mixture from coke oven (COG), steelmaking process “Linz-Donawitz” (LDG) and blast furnace (BFG); with the production of steel laminates being its main activity. Two methods were developed in this work to deal with energy consumption. The first dealt with improved estimation of heat losses in the furnace, and the second dealt with recovery of heat and its use in load preheating and combustion air preheating. These evaluations were intended to determine the best selection of material for insulation of the furnace, in order to increase heat transfer, to obtain an economy in fuel consumption, and to improve technical energy indicators of production and heat generation, as well as to improve the efficiency of the furnace and the combustion process. When developing the present study in the reheating furnace it was evidenced an economy in the fuel consumption of the COG/LDG mixture of 6606 m3/h and 4627 m3/h for the load preheating and the air preheating, respectively. In addition, efficiency of the furnace was increased by 23.3% and 15.2%, with the technical energy indicators improved by 18.9% and 13.2% in each case. For the COG/BFG mixture, the results obtained were similar.
This study aims to validate the new developments in our in-house spectroscopic code (KAT-LIF) to perform NO-LIF simulations for detonation conditions, as well as evaluating the capabilities of the ...NO-LIF diagnostic for characterizing H
2
-air detonations. This objective was achieved in several steps. First, our in-house spectroscopic tool, KAT-LIF, was updated to perform NO-LIF simulations by notably developing a database of NO(A-X) transitions, currently unavailable in conventional spectroscopic databases, as well as collecting and implementing species-specific line broadening, line shifting, and quenching parameters for NO-LIF. Second, the validation of KAT-LIF was performed by comparing the simulation results with pre-existing simulation tools (LIFSim and LIFBASE) and experimental NO-LIF measurements in a laminar CH
4
-air flame and H
2
-air detonation. The validation results present satisfactory agreement of KAT-LIF and other simulation tools (LIFBASE, LIFSim) with experimental results for several conditions. For example, less than 20% discrepancy between the simulated and experimental NO-LIF profiles is observed for stoichiometric H
2
-air detonation, initially at 20 kPa and 293 K. Third, qualitative and quantitative capabilities of the NO-LIF technique for detonation characterization are discussed, which include: shock detection, induction zone length measurements, and quantitative number density measurements.
We present a formalism to compute Brownian thermal noise in functional optical surfaces such as grating reflectors, photonic crystal slabs, or complex metamaterials. Such computations are based on a ...specific readout variable, typically a surface integral of a dielectric interface displacement weighed by a form factor. This paper shows how to relate this form factor to Maxwell’s stress tensor computed on all interfaces of the moving surface. As an example, we examine Brownian thermal noise in monolithic T-shaped grating reflectors. The previous computations by Heinert et al. Phys. Rev. D 88, 042001 (2013) utilizing a simplified readout form factor produced estimates of thermal noise that are tens of percent higher than those of the exact analysis in the present paper. The relation between the form factor and Maxwell’s stress tensor implies a close correlation between the optical properties of functional optical surfaces and thermal noise.
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