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Palm fatty acid distillate PFAD is an example of potential low-cost palm biofuel second generation feedstock, most used as a source of fatty acid for non-food applications in industry. Catalytic application of Oxone® salt was used in the present study for the esterification reaction of PFAD for biodiesel production for the first time. After optimizing the conversion rate, was possible to observe that, among the process variables studied [Oxone® concentration (%), temperature (°C) and reaction time (h)], Oxone® concentration was the only significant variable for the fatty acid ethyl esters (FAEEs) generation response variable. A > 90% conversion rate was reached with 15% Oxone® at 42 °C, using a PFAD:ethanol molar ratio of 1:5 at 12 h reaction time. The reaction system has a series of advantages, such as mild conditions, simple operation, green and high conversion. As alternative for make the biodiesel production as sustainable as possible.

The confinement of electromagnetic waves in a metal-dielectric interface involves a series of applications of practical interest, including optical absorption at interfaces, solar cells, and sensors. The condition used to obtain confinement appears to be insufficient to guarantee the observation of phenomena. In this work, an analytical study of confinement conditions was done without assumed approximations for permittivity. Thus, it has been possible to separate the real and imaginary parts of the wave vector and find the general conditions for confinement, which shows that in several metal-dielectric interfaces, you cannot have a confined wave. This obtained result shows that the wave in interface can cease to exist even with a small change in dielectric constant. Based on these new conditions, we reviewed a wide range of materials that can be used as adjacent to traditional metals (Ag and Au) and calculated their solar cell’s efficiency and the length of propagation.

Economically viable alternatives for utilizing municipal solid waste are still a major challenge for society, especially in less developed countries. A potential pathway is using the organic fraction of municipal solid waste (OFMSW) to produce energy, biofuels, organic fertilizers, and value-added chemical compounds. We evaluated an integrated biorefinery structure for the treatment of used cooking oil, pruning biomass, and organic and food residues to produce biodiesel, biogas, organic compost, 1,3-propanediol, and electrical energy at the campus of the Federal University of Pernambuco, which was considered a case study to represent a small city of Northeastern Brazil. A pilot transesterification plant, a biodigestion unit, and a compost unit were installed to process 3.3 tons daily of OFMSW produced. Additionally, research was carried out to produce 1,3-propanediol on a laboratory scale from residual glycerol. The quality of the biodiesel generated from the used cooking oil met national technical standards and the conversion of residual oil into biodiesel reached 93%. The average biogas production was 0.584 ± 0.176 Nm3 kgVS−1, with an average methane production of 50% generating up to 44 MWh of electricity per year. The organic compost produced met the quality requirements of organic fertilizers, such as maturation and nutrient contents. Glycerol treatment increased the yield of 1,3-propanediol production. Our findings demonstrate that the integrated biorefinery will lead to a reduction of US$ 80,000 in the costs of OFMSW management. More importantly, this approach generates incentives for circular economy initiatives in small municipalities in Brazil and other less developed countries.

This letter provides a methodology to analyze noise sensitivity of quaternion and axis-angle representations in the presence of joint measurement noise. A general formulation based on the trace of the rotation matrix is proposed, enabling to compute noise sensitivity as a function of robot postures and noise variances. Additionally, noise sensitivity as a function of the orientation angle is derived, enabling to identify regions with different sensitivities. The theoretical findings are general and are not associated to any particular noise distribution. Simulation results with zero-mean Gaussian noise and real experiments are provided corroborating the theoretical findings.

Enhancement of luminescence properties to improve and/or control both the absorption and emission of lanthanide (Ln)-activated glasses, ceramics and glass-ceramics, can be achieved with the development of smart photonic systems. Among different possible strategies, a prospective proof of concept for photoluminescence (PL) enhancement based on a one-dimensional photonic crystal (PC) was designed to tailor the up-conversion (UC) emission of Er3+ from a microcavity (MC) with an aluminosilicate glass film co-doped with Er3+/Yb3+ sandwiched between alternating layers of undoped aluminosilicate and TiO2. For the fabrication, the layers of different materials were deposited by sol-gel (SG), in order to mimic the PC structure obtained by simulation for a pre-defined position of the pass band defect (547 nm) within the stop band. An enhancement of up to 13 times of the Er3+ green UC was observed for the MC in comparison with a system without the PC structure.

In this work, we report the obtention of the LDH@Bi2WO6 heterostructure using an easy and low-cost method. The LDH was synthesized through the co-precipitation method with the metallic ratio of Mg2+/Al3+ = 2.0, while the bismuth tungstate nanoplates were prepared using the hydrothermal method. The LDH@Bi2WO6 heterostructure was obtained mixing LDH in water with 20 wt% of Bi2WO6. The LDH, Bi2WO6 and LDH@Bi2WO6 heterostructure were characterized by XRD, FTIR, N2 sorption, SEM, TEM, Raman, and DRS. The photocatalytic activity of these materials was evaluated by the photodegradation of RhB in aqueous solution under simulated sunlight irradiation. The characterization revealed the deposition of LDH on the surface of Bi2WO6, as well as a considerable increase in the photocatalytic activity (synergistic effect) of the LDH@Bi2WO6 heterostructure when compared with pure LDH and Bi2WO6. For this material, the degradation rate, velocity constant rate, and half-life time experimentally obtained were equal to 98.7%, 51.9 × 10–3 min−1, and 13.3 min, at the end of 75 min in the photodegradation of RhB. It is also 166 times faster than the photolysis test, with a high stability after five consecutive photocatalytic cycles. Therefore, the LDH@Bi2WO6 heterostructure is a promising material in the photodegradation of organic pollutants using visible-light as the source of radiation.

Recently, green chemistry for the development of sustainable production systems requires tremendous research efforts on the design of catalysts through resource-efficient ways. The improvement of their catalytic performances is a key goal in modern society. Several approaches using environmentally friendly chemicals and materials for less hazardous synthesis and catalysis were analyzed. In this review, we focus on the synthesis of nanomaterials and catalytic applications to reduce the environmental impact, especially, by reducing waste, solvents, precursors, and derivatives. In addition, we highlight the special efforts toward the use of renewable feedstocks and their applications as well as the synthetic routes to develop nanocatalysts using a greener chemistry.

One of the biggest challenges of current times is to reduce the global dependence on fossil fuels. In this scenario, several approaches have been taken to implement efficient processes of biofuel generation from lignocellulosic materials. Here, some of the most recent relevant results are presented. The waste valorization, design of new/more efficient catalysts, the improvement of characteristics by genetic engineering organisms, and the development of new and/or step integration processes, among other possibilities, are important tools to increase and make more relevant the role of renewable fuels in the global energy matrix.

Eugenyl acetate has been investigated because of its beneficial bioactive antioxidant, antimicrobial and potential properties against the development of Aedes aegypti larvae. Here, we report, for the first time, the use of a catalyst prepared from flint kaolin with microwave irradiation for the acetylation of eugenol. A few kinetic parameters were evaluated in the experiments used for eugenol ester synthesis. High conversions (98%) were obtained after 1 h of reaction. The prepared material shows good activity (over 90%) even after 4 cycles of use. Therefore, the use of microwave radiation made it possible to prepare a catalyst in a very short time using a low-cost industrial by-product as a raw material that proved to be highly active, in addition to the additional advantage of being reusable, which would reduce possible environmental impacts caused by its disposal in the environment.

Water pollution by organic pollutants such as textile dyes is a serious problem that could be solved by advanced photocatalytic semiconductors. Here we synthesized a visible-light photocatalyst made of mesoporous graphitic carbon nitride using the surfactant Tween-40, and we compared the surfactant performance in degrading rhodamine B with graphitic carbon nitride prepared by conventional methods. The toxicity of the photocatalyst was evaluated using bioassays with Allium Cepa. Results show that 93.0% of the rhodamine B was degraded by the new catalyst after 60 min under visible-light irradiation, whereas bulk graphitic carbon nitride and mesoporous graphitic carbon nitride with Pluronic F127 degraded only 30.5 and 86.0% of rhodamine B, respectively. We also found no ecotoxicity of the new catalyst. Higher degradation performance of the photocatalyst is explained by synergistic effect of nitrogen vacancies combined with the higher number of structural defects and more active sites, and by a better separation and transport of photogenerated charges of the synthesized mesopore catalyst, thus inducing a better response under visible light.

In order to increase the efficiency of photovoltaic solar cells, photon absorption in an extended range of the solar spectrum is necessary, for example by means of up-conversion (UC) of sub-bandgap photons to minimize transparency losses. While lanthanide (Ln)-doped luminescent layers may be deposited on cell materials to achieve spectral conversion by methods like CVD or PVD, sol-gel (SG) processing is a low-cost technology which may be a good alternative for this purpose. In this work, Ln-doped SG-derived active layers have been deposited by spin-coating onto c-Si substrates for frequency conversion, with particular emphasis on UC, involving host matrices like aluminosilicate glass and titania ceramic doped with the activator/sensitizer pair Er/Yb. White light emitting diodes (WLEDs) based on Ln-doped phosphors still have efficiency limitations, namely because the Stokes shift from UV/blue LED excitation to the emitted lower frequency visible light converts some of the pump energy into heat. However, if white light generation (WLG) is achieved through IR-pumped UC instead, the cost of the LED lamp will be reduced, while the energy loss from Stokes shift can be minimized. SG synthesis of Ln-doped oxide phosphors for UC in WLG has been achieved (Er/Yb and Tm/Er/Yb doping), based on aluminosilicate glass matrices. Photonic crystal-assisted UC emission has also been demonstrated in a Tm/Yb-doped Fabry–Perot microcavity (MC). The different materials have been characterized by XRD, SEM, ellipsometry and photoluminescence (PL) spectroscopies and their light emission has been analyzed with the help of CIE chromaticity diagrams.

Traditional post-hoc high-fidelity scientific visualization (HSV) of numerical simulations requires multiple I/O check-pointing to inspect the simulation progress. The costs of these I/O operations are high and can grow exponentially with increasing problem sizes. In situ HSV dispenses with costly check-pointing I/O operations, but requires additional computing resources to generate the visualization, increasing power and energy consumption. In this paper we present LOOM, a new interweaving approach supported by a task scheduling framework to allow tightly coupled in situ visualization without significantly adding to the overall simulation runtime. The approach exploits the idle times of the numerical simulation threads, due to workload imbalances, to perform the visualization steps. Overall execution time (simulation plus visualization) is minimized. Power requirements are also minimized by sharing the same computational resources among numerical simulation and visualization tasks. We demonstrate that LOOM reduces time to visualization by 3 × compared to a traditional non-interwoven pipeline. Our results here demonstrate good potential for additional gains for large distributed-memory use cases with larger interleaving opportunities.

Harvesting solar energy demands efficient solar cells working over the largest region of the solar spectrum possible. The extension of the wavelength region is viable through the use of frequency converting phosphors. Rare earth (RE) pairs fulfill this criterion and in particular the Erbium/Ytterbium pair allows a good coverage from the near-infrared (NIR) to visible by up conversion (UC) at room temperature. In this study we report the structural and optical properties of aluminosilicate glass films grown by sol-gel (SG) spin-coating deposition technique and co-doped with (Er, Tb)/Yb by ion implantation with different fluences and energy. After implantation, the films were annealed at 1000 °C for 20 min and characterized by scanning electron microscopy (SEM), Rutherford Backscattering (RBS), X-ray diffraction (XRD) and Photoluminescence (PL). The annealing induces a significant redistribution of the RE ions in the films. In particular, the samples implanted with Tb + Yb show a tendency to form a homogeneous distribution over the entire film. In both cases PL shows the cooperative up conversion process.

Egeria densa is a submerged aquatic plant species, with a high capacity for colonization and growth. Its proliferation has caused serious problems in hydroelectricity generation, due to biomass accumulation in turbine containment grids. Bioprocessing of macrophytes may be an alternative for using this biomass to produce bioenergetic products such as biofuels. The cell wall of macrophytes is a lignocellulosic material with a complex lignin-hemicellulose-cellulose network, which may require pretreatment to provide the fermentable sugars as substrate prior further processing. This work aims to evaluate a physicochemical pretreatment of E. densa, with the objective of making its structure suitable for bioprocessing. Full factorial 23 analysis was performed for different concentrations of the reagents and reaction times. The variable responses were delignification, total carbohydrate yield and crystallinity grade. Results showed greater efficiency for alkaline hydrolysis, but both processes were viable for removing amorphous compounds and for increasing bundling of cellulose molecules.

The genesis of Planosols is a complex process since it can involve multiple cycles of soil formation, deposition of allochthonous materials and also past climate changes. Furthermore, this subject is still poorly studied in the humid tropics, thus hindering a proper appraisal of the potentials and limitations of Planosols. The objective of this research was to study pedogenetic processes and properties of Planosols formed from different parent materials in southern Brazil. Four soils were sampled: (P1) Hypereutric Luvic Albic Planosol, developed on lagoon plain sediments; (P2) Orthoeutric Luvic Albic Planosol, on Holocene alluvial deposits; (P3) Hypereutric Luvic Albic Planosol, on granite; and (P4) Orthoeutric Luvic Albic Planosol, on gneiss. All Planosols presented sandy horizons A and E, with low pH (

Despite of the ecological importance of several batoids caught as bycatch, little attention is given to the individual resilience in risk assessments. The report of physical condition is imperative for a realistic understanding of the impacts caused by fishing, as a way to reduce the negative consequences of bycatch and improvement of management protocols. In this context, the present study provides an analysis of injuries observed in nine species of batoids caught by small scale fisheries by adopting a non-lethal approach. Levels of injury were determined according to severity and the relation between fishing time and injury/mortality was assessed. Results showed that injury levels and release condition were strongly influenced by fishing effort and time until release, with fishing effort lower than 110 min related with minor injuries, lower capture mortality rates (10.6%) and better release conditions. Since the frequency of batoids in small scale fisheries as accompanying fauna is high, the cooperation between researchers, fishermen and authorities is essential to reduce the negative consequences of bycatch. Based in the data presented here, we recommend that management plans establish fishing effort times and immediate release in areas of ecological importance for endangered species, thus helping to promote batoids conservation.

The synthesis of aluminosilicate Al-MCM-41 was performed using mining kaolin waste as an alternative source of silicon and aluminum to add value to this waste. In a preliminary stage, acid leaching was carried out with the kaolin residue with three different durations (1, 1.5 and 2 h) to evaluate the leaching time that provided the highest amounts of silicon and aluminum in the tailings. Molecular sieves were synthesized by the hydrothermal method and calcined at 550 °C to eliminate the surfactant. X-ray diffractograms of the synthesized samples revealed that the sample AM41-2H, obtained from kaolin leached for 2 h (MC7-2H), presented the best structural arrangement due to the presence of 2θ angles close to 2.32°, a specific surface area of 1016 m2·g–1, a pore volume of 0.80 cm3·g–1, and a pore diameter of 3.14 nm, which are characteristic of Al-MCM-41. A sample of AM41-2H was functionalized with 3-mercaptopropyltrimethoxysilane (MTPS) (5 mmol MTPS/g AM41-2H). To eliminate excess unaltered MTPS on the sur...

This paper reports on the optical properties of new organic metal halide material [C6N2H5]3BiCl6. The crystal structure is built up from the packing of distorted [BiCl6]3- octahedra surrounded by organic cation [C6N2H5]+. Unlike the classical metal halide materials in which organic molecules are optically inactive, both organic and inorganic components in this structure are chromospheres. At ambient temperature, photoluminescence measurements show and intense emission in the yellow green region. This emission is believed to be due to π– π* electronic transition within the organic cation [C6N2H5]+. Optical absorption (OA) and photoluminescence (PL) spectra of this compound were analyzed and interpreted by comparison with those of the homologous hybrids on one hand and those of the organic molecules on the other hand. In addition, photoluminescence excitation (PLE) have shown that the intense emission is governed by a resonance energy and charge transfer process in which [BiCl6]3- ions is assumed as a donor and organic cation plays the role of an acceptor. Moreover, photoluminescence study as function of temperature using the Arrhenius model, reveals the behavior a quasi-localized exciton with a binding energy of 73 meV, substantially lower than those found for homologous compounds but it reflects the localized character of the exciton and it may explain the stability of the exciton at ambient temperature.

Transition metal ions are essential micronutrients for all living organisms and play an important role in bone metabolism. In the present study, we investigated the impact of transition metal ions (Cu, Co, Mn, Fe) on the structure and bioactivity of bioactive glasses. The emphasis was laid on understanding their influence on the chemical dissolution behavior of glasses and its impact on their vitro bioactivity, osteoblast proliferation and oxidative stress levels. The structure of glasses was studied by using molecular EXAFS in combination with Raman spectroscopy. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy after immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 and 7 days. A significant effect on the bioactivity was observed with addition of transition metal ions. The cellular responses were observed in vitro on glass powders using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of transition metal ions (Cu, Co, Mn, Fe) released from the glasses is also discussed.

In Portugal, news shows that the impact of COVID-19 in the hospitality sector was more noticeable compared to other sectors. This chapter aims to understand the historical trends of hotel industry financial leverage and to analyse the impact of macroeconomic factors on it. Based on the Portuguese reality, it aims to propose a model to be used by managers and shareholders to control the effect of financial leverage over their companies. Two issues are supporting this study: one is if companies evaluate the impact of the chosen financing sources on shareholders' return; another is to understand whether there is a change in the financial leverage effect, either due to macroeconomic factors or due to cyclical factors not controlled by the market, such as the current pandemic (COVID-19) which demands new challenges to companies. Results highlight that the perception of financial leverage by hotel managers is crucial in crisis situations, as the current case of the pandemic caused by COVID-19.

The distillate from the deodorization of palm oil (DDPO) is an agro-industrial residue, approximately 84% of which consists of free fatty acids (FFAs), which can be used for the production of fatty acid ethyl esters (FAEE). A catalyst (10HPMo/AlSiM) obtained from a waste material, Amazon flint kaolin, was applied in the esterification of the DDPO, reaching a conversion index of 94%, capable of maintaining satisfactory activity (>75%) after four consecutive cycles. Flint kaolin is therefore proven to be an efficient option in the search for new heterogeneous low-cost catalysts obtained from industrial by-products, contributing to the reduction of environmental impact and adding value to widely available wastes that would otherwise be discarded directly into the environment. Based on the catalytic results, esterification of DDPO using 10HPMo/AlSiM can be a cheaper alternative for the production of sustainable fuels.

A combined strategy to control the release of two drugs, one anti-inflammatory (diclofenac sodium, DCF) and one antibiotic (moxifloxacin hydrochloride, MXF), from a soft contact lens (SCL) material, was assessed. The material was a silicone-based hydrogel, which was modified by molecular imprinting with MXF and coated by the layer-by-layer (LbL) method using natural polyelectrolytes: alginate (ALG), poly- l -lysine (PLL) and hyaluronate (HA), crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Imprinting was used to increase the amount of MXF loaded and to sustain its release, while the LbL coating acted as a diffusion barrier for DCF and improved the surface properties. The drugs were loaded by soaking in a DCF + MXF dual solution. High hydrostatic pressure (HHP) was successfully applied in the sterilization of the drug-loaded hydrogels. The transmittance, refractive index, wettability and ionic permeability of the hydrogels remained within the required levels for SCLs application. The concentrations of the released DCF and MXF stayed above the IC50 and the MIC (for S. aureus and S. epidermidis) values, for 9 and 10 days, respectively. No ocular irritancy was detected by the HET-CAM test. NIH/3T3 cell viability demonstrated that the drug-loaded hydrogels were not toxic, and cell adhesion was reduced.

A new mesoporous Zn1-xMxAl2O4 photocatalyst was prepared using the metal-chitosan complexation method with different degrees of Zn2+ cation substitution with cobalt and nickel ions (M = Co2+ and Ni2+). Characterization using X-ray diffraction (XRD), Infrared absorption spectrometry (FTIR), energy dispersion spectroscopy (EDS), diffuse reflectance spectrometry (DRS), scanning electron miscoscopy (SEM), transmission electron miscroscopy (TEM), N2 adsorption- desorption isotherms using the Barrett-Joyner-Halenda (BJH) method, thermogravimetric analysis (TG) and differential thermal analysis (DTA) confirmed the formation of the spinel phase and high purity for all samples. N2 adsorption/desorption and size pore distribution confirmed the high surface area. The photocatalytic activity of Zn1-xMxAl2O4 and the effect of replacing Zn2+ ions with Ni2+ and Co2+ on the degradation of rhodamine B under ultraviolet light were studied in detail. The sample containing 0.1 mol of cobalt had the highest removal rate reaching 83%, favored by surface area and material bandgap (109 m2 g&minus, 1 and 2.19 eV, respectively).

Optically detectable labels and probes are commonly used in bioapplications. Together with the miniaturization of analytical platforms based on microfluidic technology, with tuneable properties, they yield unparalleled opportunities towards faster, cheaper and more efficient biomolecule analysis. This work describes the preparation and testing of uniformly shaded polydimethylsiloxane (PDMS) membranes and microfluidic devices used to enhance or inhibit optical detection of fluorescent labels. The uniformly pigmented black-PDMS nanocomposite mixtures have been prepared by adding a known quantity of black pigment to PDMS, and its optical, spectroscopic and morphological properties have been characterized. The effect of pigment-to-DMS mixing ratio has been investigated by Ultra-Violet/Visible, near infrared and middle infrared spectroscopies; scanning electron microscopy and atomic force microscopy; and contact angle measurements. The results demonstrate that optical and spectroscopic properties of black-PDMS are strongly altered with the progressive inclusion of black pigment while wetting behaviour and morphology are maintained. Surface contact angle decreases more prominently with the decreasing ratio of DMS-to-curing agent than for the inclusion of pigment nanocomposite in the mixture. The ability to tune optical properties of PDMS has been experimentally demonstrated in a Black-PDMS nanocomposite microfluidic chip cast and bonded to glass. The results show double the signal-to-noise in fluorescence images as compared to pure PDMS devices, demonstrating a very promising integrated optical detection strategy for portable microfluidic systems.

A key challenge in second generation solar cell development is to overcome major energy losses and to obtain high efficiency homogeneous films. In order to take advantage of the major portion of the solar spectrum, minimizing transparency losses, the use of frequency converting phosphors is a promising solution. From this viewpoint, the development of up-conversion (UC) materials for improving the light harvesting efficiency is a demanding task. Here, we report a low cost sol-gel (SG) spin-coating deposition technique which allows scalability to deposit SiO2 – Al2O3 and TiO2 films doped with the Erbium/Ytterbium lanthanide pair to obtain functional coatings with efficient near-infrared (NIR) to visible UC photoluminescence (PL) at room temperature. An alternative direct incorporation of the lanthanide ions into the solar cell material was also achieved by ion implantation. Comparison of both methods indicates that, although ion implantation is an accurate and controllable doping method, UC emission is superior at present from the films obtained by solution doping. However, this is the first time, to the best of the authors' knowledge, that UC properties have been studied for the Er/Yb pair in this system by this route. Therefore, the results reported here provide an additional approach for better understanding the doping parameters needed to obtain high PL performance.

The demand for microbial lipids as possible fossil fuel substitutes has prompted worldwide synthetic biofuel research. The present study surveyed the lipid profiles of three Amazonian cyanobacterial strains, Cyanobium sp., Limnothrix sp. and Nostoc sp. cultivated in two culture media, ASM-1 and BG-11, to evaluate their fatty acid composition and to measure biodiesel quality parameters. All strains showed good growth in the two culture media, but the Limnothrix sp. had a better lipid profile and produced high amounts of C16: 0, which is favorable for the production of biodiesel. This strain also had better biodiesel quality parameter values showing high oxidative stability (34.90 h) and a cetane number (58.06) above the minimum established by the ASTM (American Society for Tests and Materials); these values were measured by the program Biodiesel Analyzer © Ver. 2.2.

Great efforts have been made in the last few years to increase the energy efficiency of solar cells. Among several factors which influence their performance, the light harvesting efficiency is the most relevant factor. In order to reduce the transparency losses of sub-bandgap solar photons, especially for wide gap solar cell materials, the development of up-conversion (UC) coatings to transform near infrared (NIR) light into short-wavelength visible photons is clearly a suitable approach. In spite of recent advances, the development of UC materials involves techniques which are generally not cost effective. This work will primarily focus on the evaluation of UC luminescence in aluminosilicate glass phosphors co-doped with the Tb3+/Yb3+ ion pair and synthesized by sol-gel (SG), a technique which is especially adequate to the deposition of films. The optimization of dopant concentrations has also been investigated, together with the structural, morphological and UC emission study of the coatings obtained. Lastly, a potential demonstrator has been developed in the form of a 1-D photonic crystal (PC) microcavity, in order to integrate the spectral conversion function into a more complex but more efficient structure.

Anthocyanins are naturally occurring flavonoids derived from the phenylpropanoid pathway. There is increasing evidence of the preventative and protective roles of anthocyanins against a broad range of pathologies, including different cancer types and metabolic diseases. However, most of the fresh produce available to consumers typically contains only small amounts of anthocyanins, mostly limited to the epidermis of plant organs. Therefore, transgenic and non-transgenic approaches have been proposed to enhance the levels of this phytonutrient in vegetables, fruits, and cereals. Here, were review the current literature on the anthocyanin biosynthesis pathway in model and crop species, including the structural and regulatory genes involved in the differential pigmentation patterns of plant structures. Furthermore, we explore the genetic regulation of anthocyanin biosynthesis and the reasons why it is strongly repressed in specific cell types, in order to create more efficient breeding strategies to boost the biosynthesis and accumulation of anthocyanins in fresh fruits and vegetables.

The spectral mismatch between incident solar photons and the bandgap of crystalline silicon in solar cells results in major energy losses. Photons with energies lower than the bandgap are lost due to transparency, while those with energies above the bandgap value will be absorbed, generating electron-hole pairs, but consuming only the energy Eg, with the excess being lost as heat through thermalization. Despite intensive research to obtain efficient down-conversion (DC) materials for frequency shifting layers in c-Si cells, their development so far involves techniques which are not cost effective. Taking this into account, aluminosilicate phosphors co-doped with the Tb3+/Yb3+ ion pair have been synthesized by sol-gel (SG) processing, a low cost technique which allows scalability and is especially useful to obtain films. The molar composition 90 SiO2-10 AlO1.5 was chosen as host to investigate if DC based on the Tb3+/Yb3+ pair leads to efficient quantum cutting in such material. We demonstrate the potential of this approach to obtain near infrared DC emission in aluminosilicate matrix with a conversion efficiency of up to 158%, with potential to improve the performance of low bandgap photovoltaic solar cells.

The trivalent Sm 3+ ion doped tellurium-antimony-tungsten oxides based glasses were prepared by conventional melt quenching and pressing method. Spectroscopic characterizations such as optical absorption, photoluminescence and decay profile measurements were performed on the glasses. Judd-Ofelt theory is used to evaluate the oscillator strengths and the three phenomenological intensity parameters (Ω λ , λ = 2, 4, 6) of the glasses. The photoluminescence spectra recorded under 479 nm excitation exhibited the emission bands at 562, 598, 645 and 708 nm corresponding to the transitions 4 G 5/2 → 6 H J ( J = 5/2, 7/2, 9/2, 11/2) respectively. Using J-O parameters (Ω λ ) various important radiative parameters viz., transition probabilities, emission cross-sections, branching ratios of various emission bands were evaluated. Decay profiles were recorded to find the lifetime of the 4 G 5/2 excited level and the obtained life time values are observed to decrease with an increase of Sm 3+ ion concentration; such decrease is attributed due to clustering of Sm 3+ ions which may cause luminescence quenching.

The present paper brings two different photochemical aspects of benzophenothiazine chemistry: (i) the use of microwave radiation to prepare three benzophenothiazines derivates; and (ii) the photophysical characterization of the isolated compounds from microwave reactions by absorption and emission spectroscopy supported by DFT calculations at B3LYP/6-31G(d,p)/PCM level. The microwave assistant reactions reduced the reactions times compared with the conventional methods, but gave the same regioselectivity. The DFT study of the ground and excited states by linear response and state specific TD-DFT, absorption and emission, vibronic resolved spectra and charge analysis showed a very good correlation with the experimental results, and point out the benzothiazine moiety as the key element of the photophysical activity.

Yb-doped YAG single crystal is commonly used as the active material in high power lasers. Sol–gel processing is a possible alternative to prepare a similar active polycrystalline ceramic at lower cost. This work describes the preparation of YAG matrix ceramics by sol–gel with a continuous replacement of Y3+ by Yb3+ in the YAG structure. X-ray diffraction showed that the cubic YAG phase was obtained for all Yb doping levels. Structural characterization by infrared and Raman spectroscopies followed the replacement of Y by Yb. Finally, Yb3+ photoluminescence spectra were recorded, together with lifetime measurements, which yielded values in the range of 0.5–0.9 ms. Using Er co-doping as an internal standard, the absolute intensities of the Yb3+ photoluminescence peaks were compared and the optimum Yb concentration for maximum photoluminescence efficiency was determined at ~50 mol% Yb. Based on the photoluminescence efficiency and the lifetime values, a figure of merit for laser operation was maximum for the 40 mol% Yb concentration.

International audience; In this study, we have investigated the use of silver cation as nucleating agent in germanotellurite glass matrix of compositions (100−x) [70TeO2–10GeO2–10Nb2O5–10K2O]–xAg2O (x=0-6 mol%), in order to promote bulk crystallization. Density measurements, differential scanning calorimetry, X-ray diffraction, UV-Vis, and Raman spectroscopies have been performed to study the crystallization process. We have observed bulk crystallization of a unique noncentrosymmetric phase, K[Nb1/3Te2/3]2O4.8, which has been investigated for its second-order optical activity. Transparent to translucent glass-ceramics have been successfully tailored under thermal treatment and second harmonic generation signals were recorded on the glass-ceramic samples as a function of their synthesis procedure. It is suggested that the second-order optical properties observed are strongly related to the organization of crystallites within phase-separated domains.

This work reports the effect of different processing parameters on the structural and morphological characteristics of MoSe2 layers grown by chemical vapour deposition (CVD), using MoO3 and Se powders as solid precursors. It shows the strong dependence of the size, shape and thickness of the MoSe2 layers on the processing parameters. The morphology of the samples was investigated by field emission scanning electron microscopy (FESEM) and the thickness of the deposited layers was determined by atomic force microscopy (AFM). Raman and photoluminescence (PL) spectroscopies were used to confirm the high quality of the MoSe2 layers. Surface composition was examined by photoelectron spectroscopy (XPS). Moreover, the MoSe2/SiOx/Si heterojunctions exhibit diode behaviour, with a rectification ratio of 10, measured at ±2.0 V, which is due to the p-i-n heterojunctions formed at the p-Si/SiOx/MoSe2 interface. A photovoltaic effect was observed with a short circuit current density (Jsc), open circuit voltage (VOC) and efficiency of -0.80 mA/cm2, 1.55 V and 0.5%, respectively. These results provide a guide for the preparation of p-i-n heterojunctions based on few-layer MoSe2 with improved photovoltaic response., Tis work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding Contracts UID/CTM/04540/2019 and UID/FIS/04650/2019. Part of this work was supported by the COST Action MP1406 “Multiscale in modeling and validation for solar photovoltaics (MultiscaleSolar)”. Te authors acknowledge the CERIC-ERIC Consortium for access to experimental facilities and fnancial support under proposal 20182042.

The present work was aimed to investigate the catalytic activity of a mesoporous catalyst synthesized from 3-mercaptopropyltrimethoxysilane (MPTS) functionalized Amazonian flint kaolin in the acetylation of eugenol with acetic anhydride. Materials were characterized by thermogravimetry (TGA), N2 adsorption (BET), X-ray dispersive energy spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and acid-base titration. The results presented proved the efficiency of flint kaolin as an alternative source in the preparation of mesoporous materials, since the material exhibited textural properties (specific surface area of 1071 m2 g&minus, 1, pore volume of 1.05 cm3 g&minus, 1 and pore diameter of 3.85 nm) and structural properties (d100 = 4.35 nm, a0 = 5.06 nm and Wt = 1.21 nm) within the required and characteristic material standards. The catalyst with the total amount of acidic sites of 4.89 mmol H+ g&minus, 1 was efficient in converting 99.9% of eugenol (eugenol to acetic anhydride molar ratio of 1:5, 2% catalyst, temperature and reaction time 80 &deg, C and 40 min reaction). In addition, the reused catalyst could be successfully recycled with 92% conversion activity under identical reaction conditions.

Thirty-six compounds were identified from aerial parts of Solidago chilensis cultivated at PAF/FIOCRUZ campus in Rio de Janeiro city (RJ) using solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) analysis. These compounds are mainly non-oxygenated mono and sesquiterpenes. Germacrene D is the major compound of two the essential oil analyzed samples (12 to 23%) and of two of the volatiles samples analyzed by SPME (central stems and dry inflorescences samples). Limonene is the major compound in the fresh inflorescences sample (about 21%). The bornil acetate is present in both volatile fractions (16%) and essential oils (7-8%). All the essential oils samples evaluated shown a great antinociceptive activity, considering the used dose of the samples (1 mg/kg) and the standard substance (50 mg/kg). Solidago chilensis is one of Brazil arnicas and it is a medicinal plant widely used by the brazilian population. Other plants of the genus Solidago are also used in traditional medicine in North America and Europe. This is the first report of SPME analysis from Solidago genus and of the antinociceptive effect from Solidago chilensis essential oil. Resumo Trinta e seis compostos foram identificados à partir de partes aéreas de Solidago chilensis cultivadas na PAF/FIOCRUZ, na cidade do Rio de Janeiro, usando microextração em fase sólida (MEFS) e analisados por cromatografia gasosa-espectrometria de massa (CG-EM). Estes compostos são principalmente mono terpenos não oxigenados e sesquiterpenos. O Germacreno D é o composto majoritário de duas amostras de óleo essencial analisadas (12 a 23%) e de duas amostras voláteis analisadas por MEFS. Limoneno é o composto majoritário da amostra de inflorescências frescas (cerca de 21%). O acetato de bornila está presente em ambas as frações, voláteis (16%) e óleos essenciais (7-8%). Todas as amostras de óleos essenciais avaliadas apresentaram boa atividade antinociceptiva, considerando a dose utilizada das amostras (1 mg/kg) e a substância padrão (50 mg/kg). Solidago chilensis é uma das arnicas brasileiras e é uma planta medicinal amplamente utilizada pela população brasileira. Outras plantas do gênero Solidago também são utilizadas na medicina tradicional na América do Norte e na Europa. Este é o primeiro relato da análise de MEFS do gênero Soligado e do efeito antinociceptivo do óleo essencial de Solidago chilensis.

Non-biodegradable single use packaging are a serious environmental problem as it generates large amounts of waste and is generally not recycled. These packages, especially those made of expanded polystyrene, can be replaced by thermoplastic starch foams. These foams have the advantage of being from renewable sources and biodegradable. However, this material is hydrophilic and becomes unusable when it is exposed to water. Hydrophobizing starch comes as an alternative to make the foams more resistant to contact with water. The purpose of the modification is to exchange starch hydroxyl groups for less polar groups such as silane groups. In this work, two silanes were used for starch silylation: 3-chloropropyl trimethoxysilane and Methyltrimethoxysilane. The foams were made using four materials: modified starch, gelatinized starch, polyvinyl alcohol and water. Results from water absorption tests and mechanical tests show that foams absorb less water and become more resistant with the addition of silylated starch.

Quantum computing has the potential to provide solutions to many problems which are challenging or out of reach of classical computers. There are several problems in rendering which are amenable to being solved in quantum computers, but these have yet to be demonstrated in practice. This work takes a first step in applying quantum computing to one of the most fundamental operations in rendering: ray casting. This technique computes visibility between two points in a 3D model of the world which is described by a collection of geometric primitives. The algorithm returns, for a given ray, which primitive it intersects closest to its origin. Without a spatial acceleration structure, the classical complexity for this operation is O(N). In this paper, we propose an implementation of Grover's Algorithm (a quantum search algorithm) for ray casting. This provides a quadratic speed up allowing for visibility evaluation for unstructured primitives in O(√N). However, due to technological limitations associated with current quantum computers, in this work the geometrical setup is limited to rectangles and parallel rays (orthographic projection)., This work was partially financed by National Funds through the Portuguese funding agency, FCT – Fundação para a Ciência e a Tecnologia – within project: UID/EEA/50014/2019. This work was partially funded by SmartEGOV/NORTE-01-0145-FEDER-000037, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (EFDR).

This paper discusses a new teleoperation approach for robotic-assisted tele-echography. A teleoperation architecture in the joint space is presented, taking advantage of kinematic similarity between master and slave manipulators. Haptic force feedback is provided based on the slave control command torque, without using force/torque sensing data. The slave manipulator is controlled in the joint space using computed torque techniques and featuring Kalman Active Observers (AOBs). Experiments in a typical telemedice scenario, assess and validate the teleoperation architecture in a clinical context, with a radiologist performing a robotic-assisted abdominal ultrasound examination on a healthy volunteer.

This paper presents a new, heterogeneous CPU+GPU attacks against lattice-based (postquantum) cryptosystems based on the Shortest Vector Problem (SVP), a central problem in lattice-based cryptanalysis. To the best of our knowledge, this is the first SVP-attack against lattice-based cryptosystems using CPUs and GPUs simultaneously. We show that Voronoi-cell based CPU+GPU attacks, algorithmically improved in previous work, are suitable for the proposed massively parallel platforms. Results show that 1) heterogeneous platforms are useful in this scenario, as they increment the overall memory available in the system (as GPU's memory can be used effectively), a typical bottleneck for Voronoi-cell algorithms, and we have also been able to increase the performance of the algorithm on such a platform, by successfully using the GPU as a co-processor, 2) this attack can be successfully accelerated using conventional GPUs and 3) we can take advantage of multiple GPUs to attack lattice-based cryptosystems. Experimental results show a speedup up to 7.6× for 2 GPUs hosted by an Intel Xeon E5-2695 v2 CPU (12 cores ×2 sockets) using only 1 core and gains in the order of 20% for 2 GPUs hosted by the same machine using all 22 CPU threads (2 are reserved for orchestrating the GPUs), compared to single-CPU execution using the entire 24 threads available., This work was supported in part by the Instituto de Telecomunicações, in part by the Fundação para a Ciência e a Tecnologia (FCT) under Grant UID/EEA/50008/2019 and Grant PTDC/EEI-HAC/30485/2017, and in part by the National Funds through the Portuguese Funding Agency, FCT—Fundação para a Ciência e a Tecnologia, under Grant UID/EEA/50014/2019. The work of A. Mariano was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Grant 382285730.

A new prepared catalyst, 12-molybdophosphoric acid (HPMo) anchored to the mesoporous aluminosilicate AlSiM, synthesized from Amazon kaolin, was characterized and used as a heterogeneous acid catalyst for the production of eugenyl acetate by acetylation of eugenol with acetic anhydride. The effect of various reaction parameters, such as catalyst concentration, eugenol/acetic anhydride molar ratio, temperature and reaction time, was studied to optimize the conditions of maximum conversion of eugenol. The kinetics studies showed that in eugenol acetylation, the substrate concentration follows a first order kinetics. The results of activation energy was 19.96 kJ mol&minus, 1 for HPMo anchored to AlSiM. The reuse of the catalyst was also studied and there was no loss of catalytic activity after four cycles of use (from 99.9% in the first cycle to 90% in the fifth cycle was confirmed), and an excellent stability of the material was observed. Based on catalytic and kinetic studies, HPMo anchored to AlSiM is considered an excellent catalyst.

In this work, a new morphology was obtained for bismuth tungstate (Bi2WO6-glyc) using a hydrothermal method with the addition of glycerol as a surfactant. In order to compare, the bismuth tungstate without glycerol as the surfactant, i.e., Bi2WO6, was synthesized. Structural characterization by XRD and Rietveld refinement confirmed the orthorhombic structure as a single phase for all samples with high crystallinity. All active modes in Raman spectroscopy for the orthorhombic phase of bismuth tungstate were confirmed in agreement with XRD analysis. N2 adsorption/desorption and size pore distribution confirmed the high surface area (85.7 m2/g) for Bi2WO6-glyc when compared with Bi2WO6 (8.5 m2/g). The optical band gap by diffuse reflectance was 2.78 eV and 2.88 eV for Bi2WO6-glyc and Bi2WO6, respectively. SEM images confirmed the different morphology for these materials, and microstructures with cheese crisp were observed for Bi2WO6-glyc (cheese crisp). On the other hand, flower-like microcrystals were confirmed for Bi2WO6 sample. The photocatalytic performance of Bi2WO6-glyc (94.2%) in the photodegradation of rhodamine B (RhB) dye solutions at 60 min was more expressive than Bi2WO6 (81.3%) and photolysis (8.2%) at 90 min.

Two bentonites from Para&iacute, ba (Northeastern Brazil) were impregnated with heteropoly phosphomolybdic H3PMo12O40 (HPMo). The materials produced were characterized by various techniques such as N2 adsorption-desorption (specific surface area, SSA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA/DTG), Scanning Electron Microscopy (SEM) equipped with Dispersive Energy X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-vis), acid-base titration analysis. The catalytic activity of these materials was tested in the esterification of a waste from palm oil deodorization and the main results obtained (about 93.3% of conversion) indicated that these materials have potential to act as heterogeneous solid acid catalysts. The prepared materials exhibited satisfactory catalytic performance even after a very simple recycling process in three reuse cycles, without significant loss of their activities.

The present paper regards the development of functional microcapsules (MCs), containing encapsulated glycerol, to act as sustainable solid curing agents for one-component polyurethane (PU) foams. They consist of silica-based MCs with an aminosilane surface treatment, obtained through sol–gel processing technique. These MCs are intended to burst and release their content only at the spraying process, in order to promote an accelerated curing of the PU foam. The superficial amino groups react with the isocyanate groups present in the PU pre-polymer, producing polyurea moieties on the MCs’ surface, which prevents the leaching of encapsulated glycerol inside the PU aerosol can. This enables the long shelf life of the product, required for commercial application. The amino-silica MCs exhibit a perfect spherical shape, without significant leaching, in opposition to silica-based MCs and led to a significant increase in the curing rate of the PU foam. The study involved various characterization techniques, such as scanning electron microscopy, Fourier transformed infrared spectroscopy, thermogravimetric analyses, leaching and curing speed evaluation.

Hydrotalcite–hydroxyapatite material (HT–HAp) was produced by co-precipitation at room temperature (10 ≤ pH ≤ 11) with ultrasonic homogenization and hydrothermal treatment for 24 h/80 °C. The main physical–chemical characteristics were studied and the catalytic potential of the material was evaluated in transesterification of soybean oil into methyl esters. Best results were obtained at 240 °C, 4 h and 12:1 molar ratio methanol/oil: conversion rate of 80.4%. Free glycerol and free acids were not observed at these conditions. HT–HAp is a promising material for catalysis and adsorption studies.

To show the risks and harm caused by the occupational exposure to the benzene, toluene, ethylbenzene and xylenes compounds (BTEX), the working conditions of 113 persons employed at gas stations in the cities of Riach?o do Jacuipe, Feira de Santana and Salvador in the state of Bahia, Brazil were investigated by experts who correlated protection measures required by law and those applied to the workers. Data collection was performed by help of a questionnaire and non-participant observation record. The age groups of the workers in the three cities surveyed were between 18 to 25 years (30.08%) and 26 to 33 years (34.51%) of the total. The study revealed an association between occupational habits of workers at gas stations and the prevalence of symptoms due to the exposure to the BTEX compounds. Regarding the use of Personal Protective Equipment (PPE) most workers wear boots. The data show that these workers reported symptoms such as headache, rhinitis, leg pain, drowsiness, cough, fatigue, insomnia, tremors and palpitations. These disorders are related back to previous exposure to BTEX compounds which is associated with inadequate occupational habits of the workers which potentiate chemical contamination in their respective environment.

AC Popa,1,2 GE Stan,1 MA Husanu,1 I Mercioniu,1 LF Santos,3 HR Fernandes,4 JMF Ferreira4 1National Institute of Materials Physics, Măgurele, 2Army Centre for Medical Research, Bucharest, Romania; 3Centro de Química Estrutural, Instituto Superior Técnico (CQE-IST), University of Lisbon, Lisbon, 4Department of Materials and Ceramics Engineering, Centre for Research in Ceramics and Composite Materials (CICECO), University of Aveiro, Aveiro, Portugal Abstract: Synthetic physiological fluids are currently used as a first in vitro bioactivity assessment for bone grafts. Our understanding about the interactions taking place at the fluid–implant interface has evolved remarkably during the last decade, and does not comply with the traditional International Organization for Standardization/final draft International Standard 23317 protocol in purely inorganic simulated body fluid. The advances in our knowledge point to the need of a true paradigm shift toward testing physiological fluids with enhanced biomimicry and a better understanding of the materials’ structure-dissolution behavior. This will contribute to “upgrade” our vision of entire cascades of events taking place at the implant surfaces upon immersion in the testing media or after implantation. Starting from an osteoinductive bioglass composition with the ability to alleviate the oxidative stress, thin bioglass films with different degrees of polymerization were deposited onto titanium substrates. Their bio­mineralization activity in simulated body fluid and in a series of new inorganic–organic media with increasing biomimicry that more closely simulated the human intercellular environment was compared. A comprehensive range of advanced characterization tools (scanning electron microscopy; grazing-incidence X-ray diffraction; Fourier-transform infrared, micro-Raman, energy-dispersive, X-ray photoelectron, and surface-enhanced laser desorption/ionization time-of-flight mass spectroscopies; and cytocompatibility assays using mesenchymal stem cells) were used. The information gathered is very useful to biologists, biophysicists, clinicians, and material scientists with special interest in teaching and research. By combining all the analyses, we propose herein a step forward toward establishing an improved unified protocol for testing the bioactivity of implant materials. Keywords: biomaterials, bioglass, in vitro biomimetic assays, proteins

Gas stations are important emissions source of benzene (C6H6), toluene (C7H8), ethylbenzene (C8H10), and ortho, meta and para-xylene (C8H10)—better known by the acronym BTEX. The objective of this study was to determine the concentrations of BTEX compounds in the ambient air of ten gas stations in the cities of Salvador and Feira de Santana, Bahia, Brazil and evaluate the health risks to workers. Passive samplers diffusive of the Radiellor 25.54 - 342.46 μgm however, it should be considered the risks due to chronic exposure of workers. Benzene concentrations in three gas stations were above the exposure limit recommended by NIOSH (3.20 × 102 μg&middotm&#87223). Samplings were also held outdoors at 250 m of two gas stations. The total concentrations of the BTEX compounds were equal to 24.97 and 35.51 μg&middotm&#87223, and benzene concentrations were about 3 - 4 times higher than the annual pattern of 5.0 μg&middotm&#87223 established by Union European, as tolerance limit for outside areas. These data confirm that the next areas of gas stations are subject to the effects of volatilization of these compounds. Additionally, the values found in the 10 gas stations for the cancer risk ranged from 4.06 × 10&#87225 - 3.78 × 10&#87224 (mean of 1.82 × 10&#87224) for workers exposed to benzene for 30 years (acceptable limit equal 1.00 × 10&#87226). The cancer risk is very high, because the values found are about 40 - 378 times above the acceptable limit and reinforce the need to adopt urgent measures to reduce or eliminate exposure of workers to the BTEX compounds. The average non-cancer risk to benzene, toluene, ethylbenzene and xylenes was 1.84, 5.76 × 10&#87223, 4.59 × 10&#87223 and 1.37 × 10&#87221, respectively (acceptable limit < 1). Only to benzene the average value

Tellurite based ternary glasses with compositions TSW: 75TeO 2 –xSb 2 O 3 –(25−x)WO 3 where x = 5, 10, 15, 20 mol% were prepared by conventional melt quenching and pressing method. The prepared samples were investigated by X-ray diffraction (XRD), Differential thermal analysis (DTA), UV-VIS absorption spectroscopy, Raman and Fourier transform-infrared (FTIR) spectroscopies. XRD patterns recorded at room temperature confirm the amorphous nature of the glasses. Thermal properties such as glass transition temperature (T g ) and thermal stability of the glasses were determined from the differential thermal analysis curves. The absorption edge of the glasses shifts towards lower wavelength with increasing antimony oxide content in the glass indicating the increase of rigidity of the glass. FTIR and Raman spectra of the glasses showed the existence of WO 4 , WO 6 , TeO 4 , TeO 3 , TeO 3+1 and SbO 3 structural units in the glass network. The gradual increase of antimony oxide content in the glass matrix causes the transformation of TeO 4 structural units to TeO 3 or TeO 3+1 . Energy band gaps (E g ) and Urbach energies (ΔE) of the glasses were obtained by using the optical absorption spectral data. Density, molar volume, oxygen molar volume and oxygen packing density (OPD) of the glass samples were calculated to evaluate the physical and structural properties of the glasses.

Urban metabolism provides a characterization of anthropogenic material flows in urban systemsand should contribute to identify the economic activities that were involved on their supply andtransformation. Typically, its quantification requires data that is not easily available in differentgeographies. This paper makes use of a methodology based on monetary input–output tables andinternational trade statistics that might be easily replicable to many metropolitan areas in theworld, and which is intended to provide a first rough estimation of urban material flows.The paper discusses the results obtained for four metropolitan areas (Lisbon, Paris, Seoul–Incheonand Shanghai), assessing the material requirements of these economies. The urban areas arecompared in terms of the quantity and the type of material input, destination of materials withinthe economy and their distribution among economic activities. The results showed that whileLisbon is the most diverse urban area in terms of the consumption of material types, it is also theurban area with the least diversified manufacturing sector.The application of this methodology to several urban areas and across multiple years enables theassessment of the technological and economic evolution of those regions