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The techno-economic feasibility of lavender essential oil supercritical CO2 extraction was studied. The process was scaled up to a pilot plant, and the extraction yield, composition, and antioxidant potential of the extracts were evaluated at 60 °C and 180 bar or 250 bar, achieving a maximum yield of 6.9% and a percentage inhibition of the extracts of more than 80%. These results drove the development of a business plan for three scenarios corresponding to different extraction volumes (20, 50, and 100 L) and annual production. The SWOT matrix showed that this is a promising business idea. The COM was calculated and an investment analysis was performed. The profitability of this process was demonstrated by means of a financial analysis for 8 years, considering a selling price of 1.38 EUR/g for the extract from the 20 L plant and 0.9 EUR/g for industrial-scale plants, supported by the price curve. The sensitivity analysis showed that the price of the equipment was the factor that could most influence the robustness of the project and the business strategy, and the financial ratios evaluation resulted in a ROE value above 57% in all cases, indicating the economic attractiveness of the process.

[EN] This research develops a novel teleoperation for robot manipulators based on augmented reality. The proposed interface is equipped with full capabilities in order to replace the classical teach pendant of the robot for carrying out teleoperation tasks. The proposed interface is based on an augmented reality headset for projecting computer-generated graphics onto the real environment and a gamepad to interact with the computer-generated graphics and provide robot commands. In order to demonstrate the benefits of the proposed method, several usability tests were conducted using a 6R industrial robot manipulator in order to compare the proposed interface and the conventional teach pendant interface for teleoperation tasks. In particular,the results ofthese usabilitytests show thattheproposedapproach is more intuitive, ergonomic,and easy to use. Furthermore, the comparison results also show that the proposed method clearly improves the velocity of the teleoperation task, regardless of the user's previous experience in robotics and augmented reality technology., This work was supported by the Spanish Government under the project DPI2017-87656-C2-1-R.

The copper(I)-catalyzed azide/alkyne cycloaddition is recognized as one of the most successful click reactions to access self-assembling amphiphilic polymer-drug conjugates (PDCs). In this way, poor water-soluble drugs can be linked covalently to hydrophilic poly(ethylene glycol) (PEG) to obtain PEGylated drug micelles that can be used as versatile carriers for the delivery of diverse therapeutic agents. In this work, two novel amphiphilic PDCs that combine PEG with privileged scaffolds well-known for their anticancer properties, such as coumarin and 5-fluorouracil, have been synthesized and characterized. These conjugates were able to self-assemble into micelles at relatively high critical micellar concentration, probably due to the large portion of hydrophilic PEG. The micelles allowed to load other anticancer drugs (paclitaxel, curcumin, and gemcitabine), providing a unique opportunity to develop promising co-delivery carriers for synergistic cancer therapy. The Korsmeyer-Peppas mathematical model was used for describing the in vitro kinetics of drug release from the micelles. Similar sustained and controlled drug release profiles were obtained for paclitaxel and curcumin in both conjugates, which was attributed to the excellent stability driven by the strong interaction between polymeric conjugates and drugs in the micelle core. In contrast, the high instability observed for the gemcitabine-loaded micelles provided an initial uncontrolled burst release of drug. A preliminary in vitro cytotoxicity study of the micelles against human pancreatic cancer cells PANC-1 and BxPC-3 was also carried out, demonstrating that both coumarin and 5-fluorouracil retain their anticancer properties after conjugation with PEG., La cicloadición de azida/alquino catalizada por cobre (I) se reconoce como una de las reacciones de clic más exitosas para acceder a conjugados de polímero-fármaco anfifílicos (PDC) autoensamblados. De esta manera, los fármacos poco solubles en agua se pueden unir covalentemente al poli(etilenglicol) (PEG) hidrofílico para obtener micelas de fármacos PEGilados que se pueden utilizar como vehículos versátiles para la administración de diversos agentes terapéuticos. En este trabajo, dos PDC anfifílicos novedosos que combinan PEG con andamios privilegiados conocidos por sus propiedades anticancerígenas, como la cumarina .y 5-fluorouracilo, han sido sintetizados y caracterizados. Estos conjugados pudieron autoensamblarse en micelas a una concentración micelar crítica relativamente alta, probablemente debido a la gran porción de PEG hidrofílico. Las micelas permitieron cargar otros medicamentos contra el cáncer (paclitaxel, curcumina y gemcitabina), lo que brinda una oportunidad única para desarrollar portadores de administración conjunta prometedores para la terapia sinérgica contra el cáncer. Se utilizó el modelo matemático de Korsmeyer-Peppas para describir la cinética in vitro de la liberación del fármaco desde las micelas. Se obtuvieron perfiles similares de liberación sostenida y controlada del fármaco para paclitaxel.y curcumina en ambos conjugados, lo que se atribuyó a la excelente estabilidad impulsada por la fuerte interacción entre los conjugados poliméricos y los fármacos en el núcleo de la micela. Por el contrario, la alta inestabilidad observada para las micelas cargadas con gemcitabina proporcionó una liberación inicial descontrolada del fármaco. También se llevó a cabo un estudio preliminar de citotoxicidad in vitro de las micelas contra las células de cáncer de páncreas humano PANC-1 y BxPC-3, demostrando que tanto la cumarina como el 5-fluorouracilo conservan sus propiedades anticancerígenas después de la conjugación con PEG.

This article contains data related to the research article entitled "Carbon dioxide sorption and melting behavior of mPEG-alkyne". The presented data gives information on the thermodynamics properties of the solvent and the polymer. The time saturation of mPEG-alkyne in supercritical carbon dioxide (scCO2) was evaluated in a high-pressure variable volume cell in different period of time at different pressure at the same temperature. The effects of pressure and temperature on the density of CO2 when it is above supercritical conditions are determined with Sanchez Lacombe and Bender Equation and compared with the NIST database and values of equation of Bender. The characteristic parameters of CO2 were determined with the equations proposed by Chengyong Wang et al. [1] and the sum of squared error was calculated for each parameter. Furthermore in this work the solubility data of scCO2/polymer mixture were correlated with Sanchez Lacombe Equation of State (SL EOS) and Heuristic model proposed by Irene Pasquali et al. [2]. This work describes the methodology for solving the SL EOS between the polymer and scCO2 and the procedure of determining the solubility parameter with the group contribution method necessary to apply the heuristic model is described., Este artículo contiene datos relacionados con el artículo de investigación titulado "Sorción de dióxido de carbono y comportamiento de fusión de mPEG-alquino". Los datos presentados brindan información sobre las propiedades termodinámicas del solvente y el polímero. El tiempo de saturación de mPEG-alquino en dióxido de carbono supercrítico (scCO 2 ) se evaluó en una celda de volumen variable de alta presión en diferentes períodos de tiempo a diferentes presiones a la misma temperatura. Los efectos de la presión y la temperatura sobre la densidad del CO 2 cuando está por encima de las condiciones supercríticas se determinan con la ecuación de Sánchez Lacombe y Bender y se comparan con la base de datos del NIST y los valores de la ecuación de Bender. Los parámetros característicos del CO 2se determinaron con las ecuaciones propuestas por Chengyong Wang et al. [1] y se calculó la suma del error cuadrático para cada parámetro. Además, en este trabajo se correlacionaron los datos de solubilidad de la mezcla scCO 2 /polímero con la Ecuación de Estado de Sánchez Lacombe (SL EOS) y el modelo heurístico propuesto por Irene Pasquali et al. [2]. Este trabajo describe la metodología para resolver el SL EOS entre el polímero y el scCO 2 y se describe el procedimiento de determinación del parámetro de solubilidad con el método de contribución de grupo necesario para aplicar el modelo heurístico.

A new sustainable green protocol for obtaining polyethylene glycol (PEG) conjugates, with a prototype molecule, which in this work was coumarin, by means of click chemistry is presented. The organic solvents commonly used for this type of reaction were replaced by supercritical carbon dioxide (scCO2). The synthesis and characterization of PEG-coumarin were successfully reported using FTIR, 1H NMR, and MALDI TOF. Subsequently, a preliminary study was carried out using the response surface methodology to examine the variables that most affect the use of scCO2 as a reaction medium. The main effects caused by these variables, individually and their binary interaction, have been estimated. The response surface methodology has been used in this work to screen variables using a factorial design 23. The p-values of temperature and pressure were 0.006 and 0.0117, being therefore the most significant variables of the response surface methodology study. Subsequently, a more intensive study has been carried out on the variables that have shown the greatest significant effect on reaction performance where an 82.32% synthesis success was achieved, which broadens the scope of the use of scCO2 as a reaction medium. The conjugated coumarin with mPEG-alkyne and coumarin were evaluated for their in vitro antioxidant activities by the DPPH radical scavenging assay and were found to exhibit substantial activities. The click product showed comparable or even better efficacy than the initial coumarin., Se presenta un nuevo protocolo verde sostenible para la obtención de conjugados de polietilenglicol (PEG), con una molécula prototipo, que en este trabajo fue la cumarina, mediante química click. Los solventes orgánicos comúnmente utilizados para este tipo de reacción fueron reemplazados por dióxido de carbono supercrítico (scCO 2 ). La síntesis y caracterización de PEG-cumarina se informó con éxito utilizando FTIR, 1 H NMR y MALDI TOF. Posteriormente, se realizó un estudio preliminar utilizando la metodología de superficie de respuesta para examinar las variables que más inciden en el uso de scCO 2como medio de reacción. Se han estimado los principales efectos causados ​​por estas variables, individualmente y su interacción binaria. En este trabajo se ha utilizado la metodología de superficie de respuesta para cribar variables mediante un diseño factorial 2 3 . Los valores de p de temperatura y presión fueron 0,006 y 0,0117, siendo por tanto las variables más significativas de la metodología de superficie de respuesta estudiada. Posteriormente se ha realizado un estudio más intensivo sobre las variables que han mostrado un mayor efecto significativo en el rendimiento de la reacción donde se ha conseguido un 82,32% de éxito de síntesis, lo que amplía el alcance del uso de scCO 2como medio de reacción. La cumarina conjugada con mPEG-alquino y cumarina se evaluó en cuanto a sus actividades antioxidantes in vitro mediante el ensayo de captación de radicales DPPH y se encontró que exhibía actividades sustanciales. El producto clic mostró una eficacia comparable o incluso mejor que la cumarina inicial.

A new sustainable green protocol for obtaining polyethylene glycol (PEG) conjugates, with a prototype molecule, which in this work was coumarin, by means of click chemistry is presented. The organic solvents commonly used for this type of reaction were replaced by supercritical carbon dioxide (scCO2). The synthesis and characterization of PEG-coumarin were successfully reported using FTIR, 1H NMR, and MALDI TOF. Subsequently, a preliminary study was carried out using the response surface methodology to examine the variables that most affect the use of scCO2 as a reaction medium. The main effects caused by these variables, individually and their binary interaction, have been estimated. The response surface methodology has been used in this work to screen variables using a factorial design 23. The p-values of temperature and pressure were 0.006 and 0.0117, being therefore the most significant variables of the response surface methodology study. Subsequently, a more intensive study has been carried out on the variables that have shown the greatest significant effect on reaction performance where an 82.32% synthesis success was achieved, which broadens the scope of the use of scCO2 as a reaction medium. The conjugated coumarin with mPEG-alkyne and coumarin were evaluated for their in vitro antioxidant activities by the DPPH radical scavenging assay and were found to exhibit substantial activities. The click product showed comparable or even better efficacy than the initial coumarin.

In this work, we sought to investigate the effects of a thiosulfinate-enriched garlic extract, co-administered with 5-fluorouracil (5-FU) or oxaliplatin chemotherapy, on the viability of colon cancer cells (Caco-2 and HT-29). We also addressed the economic feasibility of a new combined treatment of this thiosulfinate-enriched garlic extract, with oxaliplatin that could reduce the dosage and costs of a monotherapy. The thiosulfinate-enriched garlic extract not only enhanced the impact of 5-FU and oxaliplatin (500 µM) in decreasing Caco-2 and HT-29 viability, but also showed a higher effect than standard 5-FU and oxaliplatin chemotherapy as anti-cancer agents. These results provided evidences for the combination of lyophilized garlic extract and 5-FU or oxaliplatin as a novel chemotherapy regimen in colon cancer cells that may also reduce the clinical therapy costs., En este trabajo, buscamos investigar los efectos de un extracto de ajo enriquecido con tiosulfinato, coadministrado con quimioterapia con 5-fluorouracilo (5-FU) u oxaliplatino, sobre la viabilidad de las células de cáncer de colon (Caco-2 y HT-29). . También abordamos la viabilidad económica de un nuevo tratamiento combinado de este extracto de ajo enriquecido con tiosulfinato, con oxaliplatino que podría reducir la dosis y los costes de una monoterapia. El extracto de ajo enriquecido con tiosulfinato no solo mejoró el impacto del 5-FU y el oxaliplatino (500 µM) en la disminución de la viabilidad de Caco-2 y HT-29, sino que también mostró un efecto mayor que el 5-FU estándar y la quimioterapia con oxaliplatino como anticancerígeno agentes.

Use of copper wire bits as simple catalyst in a click chemistry reaction using supercritical CO2 has been achieved. The use of this catalyst in the reaction between polylactic acid (PLA) and coumarin allows to remove the whole amount of catalyst in the final product with a simple purification step using a green solvent where no toxic solvent is used in order to synthetize the product., Se ha logrado el uso de brocas de alambre de cobre como catalizador simple en una reacción química clic usando CO2 supercrítico . El uso de este catalizador en la reacción entre el ácido poliláctico (PLA) y la cumarina permite eliminar la cantidad total de catalizador en el producto final con un simple paso de purificación usando un solvente verde donde no se usa ningún solvente tóxico para sintetizar el producto.

[EN] This article develops a human-robot cooperation to carry out treatments such as sanding, polishing, etc. on the surface of a known rigid object. For this purpose, a vision system is considered to get the object location to ensure not only the perpendicularity of the obot tool to the object surface but also a smooth approach of the tool to the surface. In order to add flexibility, the proposal includes the simultaneous combination of automatic and manual modes of operation. Thus, the human user can guide the robot tool to treat arbitrary areas (manual mode) and, when the operator releases the tool, the robot goes into the automatic mode to treat prior established areas. The method uses a task prioritization framework and three types of controllers: an admittance controller for the tool guidance; a hybrid controller to modify the tool orientation and, in the automatic mode, the tool position; and a sliding mode controller to limit the velocity at which the tool approaches the object surface. The applicability and efficacy of the proposed method is demonstrated experimentally using a conventional 6R robot arm., This work was supported in part by the Spanish Government, and in part by the Generalitat Valenciana under Grant DPI2017-87656-C2-1-R and Grant ACIF/2019/007.

Background: Chemical industry has increased the investment into and innovation capacity to supply chemicals from safe and sustainable sources, which will be essential to offering new solutions and supporting the green transition of the global economy and society. In this sense, the use of green solvents and reusable heterogeneous catalysts has emerged as a promising sustainable process strategy for engineering, chemistry and the environment. In this work, different homogeneous (copper bromide, CuBr and copper(II) acetate, Cu (CH3COO)2·H2O) and heterogeneous (Cu Wire, Cu Plate, Cu/β-SiC, pre-treated Cu Wire and pre-treated Cu Plate) copper catalysts were tested for the copper(I)-catalyzed alkyne–azide cycloaddition (CuAAC) reaction. In addition, the influence of different reaction media was analyzed, comparing the use of an organic solvent such as toluene and a green solvent such as supercritical CO2 (scCO2). Methods: Characterization of the catalysts includes by X-ray diffraction (XRD), Scan Electron Microscopy (SEM), Atomic absorption spectrophotometry (AA) and Temperature Programmed Reduction (TPR). Parameters such as catalyst loading, reaction time, reusability and leaching of the catalysts were studied to obtain more information on the CuAAC reaction in scCO2. Results: The pre-treated copper plate achieved a 57% increase in reaction yield compared to the non pre-treated copper plate. However, the recovery and reuse of the pre-treated copper plate showed a severe deterioration and a considerable change in its surface. Cu Wire (without pre-treatment) achieved yields of up to 94.2% after reusing it for five cycles. Conclusions: These results suggest the possibility to exploit the combination of heterogeneous catalysts and scCO2 and justify further research to highlight green solvents and simultaneously address the challenges of reaction, purification and recycling, Antecedentes: La industria química ha aumentado la inversión y la capacidad de innovación para suministrar productos químicos de fuentes seguras y sostenibles, lo que será esencial para ofrecer nuevas soluciones y apoyar la transición ecológica de la economía y la sociedad mundiales. En este sentido, el uso de disolventes verdes y catalizadores heterogéneos reutilizables ha surgido como una estrategia de proceso sostenible prometedora para la ingeniería, la química y el medio ambiente. En este trabajo, diferentes compuestos homogéneos (bromuro de cobre, CuBr y acetato de cobre(II), Cu (CH 3 COO) 2 ·H 2O) y catalizadores de cobre heterogéneos (alambre de Cu, placa de Cu, Cu/β-SiC, alambre de Cu pretratado y placa de Cu pretratado) se probaron para la reacción de cicloadición de alquino-azida catalizada por cobre (I) (CuAAC). Además, se analizó la influencia de diferentes medios de reacción, comparando el uso de un disolvente orgánico como el tolueno y un disolvente verde como el CO 2 supercrítico (scCO 2 ). Métodos: La caracterización de los catalizadores incluye difracción de rayos X (XRD), microscopía electrónica de barrido (SEM), espectrofotometría de absorción atómica (AA) y reducción de temperatura programada (TPR). Se estudiaron parámetros como carga de catalizador, tiempo de reacción, reutilización y lixiviación de los catalizadores para obtener más información sobre la reacción de CuAAC en scCO 2. Resultados: La placa de cobre pretratada logró un aumento del 57 % en el rendimiento de la reacción en comparación con la placa de cobre no pretratada. Sin embargo, la recuperación y reutilización de la placa de cobre pretratada mostró un severo deterioro y un cambio considerable en su superficie. Cu Wire (sin pretratamiento) logró rendimientos de hasta el 94,2 % después de reutilizarlo durante cinco ciclos. Conclusiones: estos resultados sugieren la posibilidad de explotar la combinación de catalizadores heterogéneos y scCO 2 y justifican más investigaciones para resaltar los disolventes verdes y abordar simultáneamente los desafíos de la reacción, la purificación y el reciclaje

Polymer aerogels reinforced with carbon nanofibers and alumina aerogels reinforced with hydroxyethyl-cellulose have been successfully synthesized by means of a pilot plant freeze-drying process. Their main physicochemical properties have been measured and compared, and their production costs have been computed. The SWOT matrix of the process has been determined from internal and external analyses, revealing the interest of these products as building insulation materials and the need of establishing a detailed economic analysis. A homemade Excel-VBA application was designed in order to determine the economic parameters of the freeze-drying process. As a consequence of the total economic and physicochemical analysis, it was concluded that the production of aerogels reinforced with hydroxyethyl-cellulose could only be recommended if they are used as an insulating material in buildings with higher thermal stability requirements., Se han sintetizado con éxito aerogeles poliméricos reforzados con nanofibras de carbono y aerogeles de alúmina reforzados con hidroxietilcelulosa mediante un proceso de liofilización en planta piloto. Se han medido y comparado sus principales propiedades fisicoquímicas y se han calculado sus costes de producción. La matriz DAFO del proceso se ha determinado a partir de análisis internos y externos, revelando el interés de estos productos como materiales aislantes para la construcción y la necesidad de establecer un análisis económico detallado. Se diseñó una aplicación Excel-VBA casera para determinar los parámetros económicos del proceso de liofilización. Como consecuencia del análisis económico y fisicoquímico total

This work studies the feasibility of supercritical technology for the improvement of the loading and release of curcumin in PLGA. We synthetized the poly (lactic-co-glycolic acid (PLGA) support as a solid block, determining the effect of PLGA molar composition in the range (20:80 to 80:20). A curcumin solubility study selected acetone, methanol and ethanol like more convenient solvents. Curcumin impregnation process was studied at atmospheric and high pressure using scCO2. High-pressure impregnation performances practically doubled bulk results, leading to values up to 86.1% and practically free of solvent in a sponge form. These samples could be commercialized without any further purification step. The release kinetics of the samples constantly delivered more than 90% of curcumin between 9 and 12 days. Compared to other technologies our samples improved significantly the combined loading and release characteristics, indicating that supercritical technology is an interesting alternative for curcumin loading and controlled delivery in medical applications., Este trabajo estudia la viabilidad de la tecnología supercrítica para la mejora de la carga y liberación de curcumina en PLGA. Sintetizamos el soporte de poli (ácido láctico-co-glicólico (PLGA) como un bloque sólido, determinando el efecto de la composición molar de PLGA en el rango (20:80 a 80:20). Un estudio de solubilidad de la curcumina seleccionó acetona, metanol y etanol. como solventes más convenientes El proceso de impregnación de curcumina se estudió a presión atmosférica y alta usando scCO 2. Las prestaciones de impregnación a alta presión prácticamente duplicaron los resultados a granel, llegando a valores de hasta el 86,1% y prácticamente sin disolvente en forma de esponja. Estas muestras podrían comercializarse sin ningún otro paso de purificación. La cinética de liberación de las muestras entregó constantemente más del 90 % de curcumina entre 9 y 12 días. En comparación con otras tecnologías, nuestras muestras mejoraron significativamente las características combinadas de carga y liberación, lo que indica que la tecnología supercrítica es una alternativa interesante para la carga y el suministro controlado de curcumina en aplicaciones médicas.

The synthesis of organic polymer aerogels reinforced with carbon nanofibers (CNF-reinforced polymer aerogels) using polyvinyl alcohol (PVA) as the polymeric matrix, by means of the freeze-drying method has been carried out. The influence of the CNF content in the polymer aerogel and the use of different solvents on the physical, morphological and mechanical properties of the final aerogel composites have been evaluated. The thermal conductivity and the porosity of CNF-reinforced polymer aerogels increased with the content of CNF. However, the density of the synthesized aerogels decreased when the CNF content was increased up to a value of 87.5 g/L. According to a dynamic mechanical analysis, the incorporation of CNF into the PVA matrix enhanced the mechanical characteristics and the glass transition temperature of the resulting CNF-reinforced polymer aerogels. On the other hand, aerogels synthesized using water as the solvent presented higher densities than those synthesized using acetone, butanol, ethanol or tert -butanol. However, their thermal conductivity values were very similar. Finally, an economic evaluation of the production of these materials using the freeze-drying technique was carried out. It was demonstrated the economic feasibility of the manufacturing process of aerogels proposed. Furthermore, no toxic pollutants were released at temperatures below 180 °C.

Poly(D,L-lactide-co-glycolide), PLGA, is a biodegradable polyester with high interest in medical industry, espe- cially when zinc (II) 2-ethylhexanoate (ZnOct2) is used as catalyst substitute in polymerization processes as a substitute of the toxic tin (II) 2-ethylhexanoate (SnOct2) together an initiator such as methanol to improve the reaction rate. This article shows the optimization of the bulk copolymerization method by using a factorial design approach on three experimental parameters: temperature (T), molar ratio monomers/catalyst (MC ratio) and molar ratio initiator/catalyst (IC ratio). Their influence on mass conversion (X) and number-average molecular weight (Mn) was also discussed. Also it provides a useful tool to select in a fast way the proper experimental conditions for the obtaining of this polymer as a previous stage in the synthesis and impregnation of biodegradable scaffolds. This analysis revealed that the most relevant variable in the process is the temperature, being desirable to use the high value (160oC) in order to obtain high values of conversion and molecular weight.

The incorporation of CO2 into new processes is one of the most important strategies for gas emissions mitigation that also would help to decrease the Carbon footprint. Recycling of wastes is also considered as a route to prevent greenhouse emissions as well as a source of interesting raw material. The process of recycling of polystyrene (PS) wastes using high-pressure CO2 as antisolvent and blowing agent in order to produce microcellular foams with enhanced properties was proposed, because the process could combine the benefits of both strategies for CO2 mitigation while high value-added materials were achieved. The technical, environmental and economical advantages of the recycling of polystyrene wastes were evaluated in an industrial and pilot-scale plant considering that CO2 could be recirculated during the process in several cycles in order to minimise its consumption while the economical profit is maximised., La incorporación de CO 2 a nuevos procesos es una de las estrategias más importantes para la mitigación de emisiones de gases que además ayudaría a disminuir la huella de Carbono. El reciclaje de residuos también se considera una vía para evitar las emisiones de efecto invernadero, así como una fuente de materia prima interesante. Se propuso el proceso de reciclaje de residuos de poliestireno (PS) usando CO 2 de alta presión como antisolvente y agente de expansión para producir espumas microcelulares con propiedades mejoradas, ya que el proceso podría combinar los beneficios de ambas estrategias para la mitigación de CO 2 mientras que el alto valor -Se lograron materiales agregados. Se evaluaron las ventajas técnicas, ambientales y económicas del reciclaje de residuos de poliestireno en una planta industrial y a escala piloto considerando que el CO 2 podría recircularse durante el proceso en varios ciclos para minimizar su consumo y maximizar el beneficio económico.

Vapor–liquid equilibria were measured for binary systems including carbon dioxide and free fatty acids such as oleic and linoleic acid, triglycerides as triolein or vegetable oils as sunflower oil, and modelled by the Group Contribution Equation of State (GC-EoS). Binary group parameters used in the calculation and prediction of CO2–triglycerides systems were obtained from the literature but in the case of CO2-free fatty acids, binary group parameters were adjusted through a parameterization strategy. At the end, a unique set of parameters could be established to model systems of vegetable oils at high pressures in the presence of CO2. Moreover, a strategy to calculate the two-phase region in a ternary diagram was also studied. The good correspondence between theoretical and experimental results suggests that the strategy and the set of binary group parameters proposed in this work can be reliable predictive tools for using GC-EoS to describe systems involving vegetable oils with a composition based mainly in free fatty acids and triglycerides, such as those which can be encountered, for example, in oil deacidification processes using supercritical CO2.

Supercritical CO2 extraction was used for the recovery of valuable aroma components with application in blending steps for fast aged rum processes. Head Alcohol, Crude and Aged Sugar Cane Spirit process streams were used to firstly quantify different concentrated aroma fractions with interest in food applications. Alcohols ratio, esters composition and carboxylic acids concentration criteria were used to determine the quality of extracts. The economical profitability of this technology was especially evident for Head Alcohol and Aged Sugar Cane Spirit extracts, since the most interesting compounds were concentrated more than 300 times compared to commercial aged rum. Additional experiments were performed in the range 8-15 MPa and 313-333 K to obtain empirical correlations to predict solubility data for further scale-up applications.

Error-correcting codes and matroids have been widely used in the study of ordinary secret sharing schemes. In this paper, the connections between codes, matroids, and a special class of secret sharing schemes, namely, multiplicative linear secret sharing schemes (LSSSs), are studied. Such schemes are known to enable multiparty computation protocols secure against general (nonthreshold) adversaries./nTwo open problems related to the complexity of multiplicative LSSSs are considered in this paper. The first one deals with strongly multiplicative LSSSs. As opposed to the case of multiplicative LSSSs, it is not known whether there is an efficient method to transform an LSSS into a strongly multiplicative LSSS for the same access structure with a polynomial increase of the complexity. A property of strongly multiplicative LSSSs that could be useful in solving this problem is proved. Namely, using a suitable generalization of the well-known Berlekamp–Welch decoder, it is shown that all strongly multiplicative LSSSs enable efficient reconstruction of a shared secret in the presence of malicious faults. The second one is to characterize the access structures of ideal multiplicative LSSSs. Specifically, the considered open problem is to determine whether all self-dual vector space access structures are in this situation. By the aforementioned connection, this in fact constitutes an open problem about matroid theory, since it can be restated in terms of representability of identically self-dual matroids by self-dual codes. A new concept is introduced, the flat-partition, that provides a useful classification of identically self-dual matroids. Uniform identically self-dual matroids, which are known to be representable by self-dual codes, form one of the classes. It is proved that this property also holds for the family of matroids that, in a natural way, is the next class in the above classification: the identically self-dual bipartite matroids.

Surface sediments from Cadiz and Algeciras Bays (southern Spain) were analysed by a sequential procedure for Cu, Zn, Cd, Pb, Fe, Ni, Cr, and Mn to determine their distribution among four geochemical phases (acid-soluble, reducible, oxidisable, and residual). The total metal content was also determined. The results showed that large amounts of metal accumulate in the interior of Cadiz Bay, whereas in Algeciras Bay, the highest levels of metal are found near the city of Algeciras and an area of major industrial activity. A comparison of metal levels with the sediment quality guidelines suggested by Long et al. (1995) showed areas in both bays in which pollution is sufficient to have noxious effects on marine organisms. Chemical partitioning of the metals revealed that Zn and Pb present the highest percentages in the reducible fraction and that Ni, Cr, and Cd are highest in the residual and reducible fractions. Cu shows the greatest proportion in the oxidisable fraction and Mn in the acid-soluble fr...

The matroid associated with a linear code is the representable matroid that is defined by the columns of any generator matrix. The matroid associated with a self-dual code is identically self-dual, but it is not known whether every identically self-dual representable matroid can be represented by a self-dual code. This open problem was proposed in [R. Cramer et al., Advances in Cryptology, Lecture Notes in Comput. Sci. 3621, Springer, New York, 2005, pp. 327-343], where it was proved to be equivalent to an open problem on the complexity of multiplicative linear secret sharing schemes. Some contributions to its solution are given in this paper. A new family of identically self-dual matroids that can be represented by self-dual codes is presented. Additionally, we prove that every identically self-dual matroid on at most eight points is representable by a self-dual code.

In this paper, we examine metal concentrations in the water and in the crustacean Balanus balanoides from the Huelva estuary, one of the most polluted estuaries in Europe. Metal levels in waters are very high, especially those of Zn, Fe and Cu. Zn presents the highest concentrations, with a mean value of 690 microg l-1 in 2001 and 301 microg l-1 in 2002. As the water flows down through the estuary toward the sea, the metal concentrations drop sharply and the pH rises. The metal concentrations in balanoides tissues are, in general, very high, undoubtedly due to the high metal pollution of the water where it lives. Metal concentrations in Balanus balanoides tissues behave similarly to those in the water, reaching maximums in the upper part of the estuary and diminishing as we approach the sea. The element that reaches the highest levels in Balanus balanoides is Zn, with a mean value of 54.6 g kg-1 in 2001 and 29.9 g kg-1 in 2002, followed by Cu and Fe. There is a significant correlation (p0.01) for concentrations of Cd, Cu, Fe, Mn, Ni and Zn in Balanus balanoides relative to their concentration in waters. Barnacles showed a great capacity to accumulate metals, especially Zn, Cu and Fe. Based on the results obtained, we can conclude that Balanus balanoides is a good tool for monitoring trace metals in the Huelva estuary.

1 Dipartimento di Ingegneria Industriale, Universita di Salerno, Salerno, 84084 Fisciano, Italy 2 Departamento de Ingenieŕia Quimica, Universidad de Castilla-La Mancha, 13004 Ciudad Real, Spain 3 Department of Agricultural, Food & Nutritional Sciences, University of Alberta, Edmonton, AB, Canada T6G 2P5 4Dipartimento di Ingegneria Chimica, Gestionale, Informatica, Meccanica, Universita di Palermo, 90128 Palermo, Italy

Fractionation by supercritical carbon dioxide (SC−CO2) might be a way to purify used frying oils, since a selective separation of the oil components based on their polarity and M.W. can be attained. In this work, we studied the purification of peanut oil used for frying by SC−CO2 continuous fractionation in a packed column. The influence of pressure (15–35 MPa) and temperature (25–55°C) on the yield and on the composition of products was determined. The composition of the top and bottom products was evaluated by using size-exclusion chromatography and other accepted chemical methods. Process conditions were selected to separate TG from degraded compounds. Experimental results indicated that the operating conditions leading to maximal TG recovery in the extract were 35 MPa, 55°C, and a solvent-to-feed ratio of 53. By operating at these conditions, it was possible to recover 97% of the TG placed on the column and about 52% by weight of the used frying oil. The composition of the purified top stream was very similar to that of fresh frying oil.

Supercritical CO2 extraction is a viable alternative process for the extraction of high-quality oil from olive husk (also known as olive pomace), a residue obtained in the production of olive oil. We analyzed the effect of pressure (100–300 bar), temperature (40–60°C), solvent flow (1–1.5 L/min), and particle size (0.30–0.55 mm) on four important quality parameters of the oil extracted with CO2: tocopherol concentration, extinction coefficients at 232 and 270 nm, and saponification value. Response surface methodology was used to obtain mathematical expressions related to the operating variables and parameters studied. Results from these experiments were also used to design a three-step sequential CO2 extraction procedure to obtain a higher-quality extract. The optimal operational sequence consisted of a first extraction step at 75 bar for 1 h using 1% (vol/vol) ethanol modifier, followed by a second extraction stage at 350 bar for 2.5 h without ethanol and a third step, also at 350 bar, for 2.5 h but using ethanol. These extraction conditions obtained an intermediate fraction of oil with 64% yield and all normal parameters according to European Commission food legislation. This fraction is suitable without any further refining. On the contrary, the oils obtained by hexane extraction and by conventional supercritical CO2 extraction at optimal conditions are suitable for human consumption after further refining. This last finding may result in improved economics of the sequential CO2 extraction process compared to the conventional extraction method with hexane.

Supercritical fluid extraction is a viable alternative process for extracting oil from olive husk, a residue obtained in the olive oil production. We analyzed the effects of pressure (P) (100–300 bar), temperature (T) (40–60°C), solvent flow (1–1.5 L/min), and particle size (D) (0.30–0.55 mm) on extraction yield, and three oil-quality parameters: acidity (OA), PV, and phosphorus content (PC). A response surface methodology based on the statistical analysis of the experimental data permitted us to obtain mathematical expressions relating the operational variables and parameters studied. At the best extraction condition of the experimental range analyzed (P=300 bar, T=60°C, D=0.30 mm, and solvent flow=1.25 L/min at standard conditions), the oil yield was 80% (w/w) with respect to hexane extraction, whereas the quality parameters OA, PV, and PC were 14% (w/w), 8 meq/kg, and 2.3·10−3% (w/w), respectively. These results were compared to those obtained by hexane Soxhlet extraction. The quality of the supercritical extract was superior, requiring only simple refining. This advantage may result in improved economics of the supercritical process in relation to the conventional extraction with hexane.

A new family of broadcast encryption schemes, which will be called linear broadcast encryption schemes (LBESs), is presented in this paper by using linear algebraic techniques. This family generalizes most previous proposals and provides a general framework to the study of broadcast encryption schemes. We present a method to construct, for a general specification structure, LBESs with a good trade-off between the amount of secret information stored by every user and the length of the broadcast message. In this way, we are able to find schemes that fit in situations that have not been considered before.

In the last few decades, several sequential extraction procedures have been developed, making it difficult to compare the results obtained by the different methods. Three extraction techniques (Tessier et al. 1979; Kersten and Forstner 1986; and the Bureau Communautaire de Reference (BCR)) were applied to four marine sediments with different trace metal contents. To be able to compare the results obtained by methods with different numbers of fractions (6 for Kersten and Forstner, 5 for Tessier, and 4 for BCR), the fractions of each method were grouped into four “equivalents” (acid soluble, reducible, oxidable, and residual). The results obtained for Cu, Pb, Zn, Cr, Mn, and Fe partitioning show that the metal distribution obtained with the three procedures is significantly different. The Tessier procedure gives the lowest concentration values in the acid soluble and oxidable fractions for most of the metals studied. On the other hand, this method usually gave the highest values for the residual fraction. Finally, in the reducible fraction, the Kersten and Forstner procedure showed the highest values for Cu, Cr, and Fe, and the Tessier procedure gave the highest values for Zn, Mn, and Pb.

Equilibrium isotherms for the uptake of potassium from polyol-water-methanol mixtures on Amberlite 252, a strong acid ion exchange resin, have been obtained in order to assess the possibility of using such a system to purify industrial polyether-polyols. The selectivity was very high. A two-step reaction scheme was proposed and equilibrium data were correlated by an equation derived according to the mass action law. Effective intraparticle diffusivities were obtained using a homogeneous model and the effects of the viscosity of the bulk solution and resin swelling on the exchange rate are discussed. A simple empirical equation correlating diffusivity with viscosity and resin swelling is suggested. Breakthrough curves were obtained under a wide range of conditions, being well correlated by the expression for breakthrough curves with rectangular isotherm. The proposed purification procedure is generally applicable to different polyol types, being economically and technically feasible.

Total concentrations of Cu, Zn, Mn, Ni, Cr, Cd, Pb, Fe, As, and Hg were determined in two marine bivalves R. decussatus and R. philippinarum from the Southern Spanish Atlantic Coast. The concentrations of Fe, Ni, Cr, Cu, and As in R. decussatus were significantly higher (p