Microalgae recycling improves biomass recovery from wastewater treatment high rate algal ponds

Microalgal biomass harvesting by inducing spontaneous flocculation (bioflocculation) sets an attractive approach, since neither chemicals nor energy are needed. Indeed, bioflocculation may be promoted by recycling part of the harvested microalgal biomass to the photobioreactor in order to increase the predominance of rapidly settling microalgae species. The aim of the present study was to improve the recovery of microalgal biomass produced in wastewater treatment high rate algal ponds (HRAPs) by recycling part of the harvested microalgal biomass. The recirculation of 2% and 10% (dry weight) of the HRAPs microalgal biomass was tested over one year in an experimental HRAP treating real urban wastewater. Results indicated that biomass recycling had a positive effect on the harvesting efficiency, obtaining higher biomass recovery in the HRAP with recycling (R-HRAP) (92–94%) than in the control HRAP without recycling (C-HRAP) (75–89%). Microalgal biomass production was similar in both systems, ranging between 3.3 and 25.8 g TSS/m2d, depending on the weather conditions. Concerning the microalgae species, Chlorella sp. was dominant overall the experimental period in both HRAPs (abundance >60%). However, when the recycling rate was increased to 10%, Chlorella sp. dominance decreased from 97.6 to 88.1%; while increasing the abundance of rapidly settling species such as Stigeoclonium sp. (16.8%, only present in the HRAP with biomass recycling) and diatoms (from 0.7 to 7.3%). Concerning the secondary treatment of the HRAPs, high removals of COD (80%) and N-NH4+ (97%) were found in both HRAPs. Moreover, by increasing the biomass recovery in the R-HRAP the effluent total suspended solids (TSS) concentration was decreased to less than 35 mg/L, meeting effluent quality requirements for discharge. This study shows that microalgal biomass recycling (10% dry weight) increases biomass recovery up to 94% by selecting the most rapidly settling microalgae species without compromising the biomass production and improving the wastewater treatment in terms of TSS removal.Peer ReviewedPostprint (author's final draft

VALIDATION OF THE PHOTOELECTRIC OPTOGAIT SYSTEM TO MEASURE RACEWALKING BIOMECHANICAL PARAMETERS ON A TREADMILL

The purpose of this pilot study was to validate the Optogait system to measure racewalking biomechanic parameters on a treadmill. Contact time, flight time, cadence and step length are some of the biomechanic parameters which influence the performance in racewalking. Five subjects were analyzed while racewalking at different speeds on a treadmill. The Optogait system was compared with a high speed video used as reference system. Flight time was overestimated by Optogait when compared with the reference system (0.025 ± 0.014 vs 0.023 ± 0.014 seconds, t = -2.43, p \u3c0,05). No differences were found in contact time or step length. Thus, the present study validates the Optogait system to measure racewalking biomechanical parameters on a treadmill

Towards Secure Scripting Development

This work reflects two separate efforts towards implementing security awareness in projects being developed using scripting languages. The same development process was used in both projects which included a specific focus on security. Besides summarizing lessons learned, this work recommends automatic tools for static code analysis to ensure that usual pitfalls are avoided from the very beginning. This work contributes with an overview of specific insights on Perl and Python security, together with a list of publicily available support tools, and how they are best applied and integrated into the development process. The proposed development framework is based on a supporting infrastructure which minimizes effort on peer reviews and allows early identification of security issues, making their resolution easier and cheaper.Sociedad Argentina de Informática e Investigación Operativ

Estudio e implementación de algoritmos de navegación y seguimiento que permitan la interacción de una instalación multi-robot con los usuarios de la misma

Se trabaja sobre una instalación artística que trata de aumentar la atención de las personas sobre su columna vertebral y el efecto que la gravedad tiene sobre la estructura corporal en general; para ello se tienen un conjunto de 10 robots autónomos con la función de interactuar entre ellos y con una persona en el exterior. Se quiere que cuando un usuario entre al campo de los robots uno de ellos (robot maestro) lo detecte, lo localice y vaya hacia él, cuando lo logré encontrar llamará a los otros robots (robots esclavos) que se colocaran en fila. El primero seguirá a la persona a través de un sensor de temperatura y los demás se seguirán entre ellos por infrarrojo. Cuando el usuario se mueva la columna de robots deberá moverse también hacia la persona. Todos los robots de la instalación disponen de sensores de infrarrojos (emisores y receptores) y de temperatura, así como de módulos de comunicación radio. Los robots son totalmente operativos a nivel de hardware, pero las pruebas de software que se han llevado a cabo indican que es necesario mejorar considerablemente los algoritmos implementados de navegación y seguimiento. Se tratará de implementar algoritmos eficientes de navegación y seguimiento que permitan la interacción de una instalación multi-robot con los usuarios de la misma. A partir de las medidas físicas obtenidas de los emisores y receptores de infrarrojos de los que disponen los robots se tratará de seleccionar los algoritmos de predicción y seguimiento de trayectoria más eficientes, para a continuación llevar a cabo su implementación sobre los mismos. En la actualidad no se cuenta con ninguna interfaz completamente confiable para la interacción con los robots de la instalación, y resulta muy importante el desarrollo de una aplicación que permita la comunicación para el monitoreo y control de los mismos para la implementación y prueba de los algoritmos de seguimiento. Dicha aplicación permitirá además la prueba de los algoritmos desarrollados antes incluso de ser implementados en los robots

Estudio e implementación de algoritmos de navegación y seguimiento que permitan la interacción de una instalación multi-robot con los usuarios de la misma

Se trabaja sobre una instalación artística que trata de aumentar la atención de las personas sobre su columna vertebral y el efecto que la gravedad tiene sobre la estructura corporal en general; para ello se tienen un conjunto de 10 robots autónomos con la función de interactuar entre ellos y con una persona en el exterior. Se quiere que cuando un usuario entre al campo de los robots uno de ellos (robot maestro) lo detecte, lo localice y vaya hacia él, cuando lo logré encontrar llamará a los otros robots (robots esclavos) que se colocaran en fila. El primero seguirá a la persona a través de un sensor de temperatura y los demás se seguirán entre ellos por infrarrojo. Cuando el usuario se mueva la columna de robots deberá moverse también hacia la persona. Todos los robots de la instalación disponen de sensores de infrarrojos (emisores y receptores) y de temperatura, así como de módulos de comunicación radio. Los robots son totalmente operativos a nivel de hardware, pero las pruebas de software que se han llevado a cabo indican que es necesario mejorar considerablemente los algoritmos implementados de navegación y seguimiento. Se tratará de implementar algoritmos eficientes de navegación y seguimiento que permitan la interacción de una instalación multi-robot con los usuarios de la misma. A partir de las medidas físicas obtenidas de los emisores y receptores de infrarrojos de los que disponen los robots se tratará de seleccionar los algoritmos de predicción y seguimiento de trayectoria más eficientes, para a continuación llevar a cabo su implementación sobre los mismos. En la actualidad no se cuenta con ninguna interfaz completamente confiable para la interacción con los robots de la instalación, y resulta muy importante el desarrollo de una aplicación que permita la comunicación para el monitoreo y control de los mismos para la implementación y prueba de los algoritmos de seguimiento. Dicha aplicación permitirá además la prueba de los algoritmos desarrollados antes incluso de ser implementados en los robots

Effects of surface stability on the morphological transformation of metals and metal oxides as investigated by first-principles calculations

Morphology is a key property of materials. Owing to their precise structure and morphology, crystals and nanocrystals provide excellent model systems for joint experimental and theoretical investigations into surface-related properties. Faceted polyhedral crystals and nanocrystals expose well-defined crystallographic planes depending on the synthesis method, which allow for thoughtful investigations into structure-reactivity relationships under practical conditions. This feature article introduces recent work, based on the combined use of experimental findings and first-principles calculations, to provide deeper knowledge of the electronic, structural, and energetic properties controlling the morphology and the transformation mechanisms of different metals and metal oxides: Ag, anatase TiO2, BaZrO3, and α-Ag2WO4. According to the Wulff theorem, the equilibrium shapes of these systems are obtained from the values of their respective surface energies. These investigations are useful to gain further understanding of how to achieve morphological control of complex three-dimensional crystals by tuning the ratio of the surface energy values of the different facets. This strategy allows the prediction of possible morphologies for a crystal and/or nanocrystal by controlling the relative values of surface energies.The authors are grateful to FAPESP (2013/07296-2, 2012/ 14468-1, 2013/26671-9 and 2014/04350-9), CAPES (process A104/2013 and 99999.002998/2014-09), CNPq INCTMN 573636/2008-7, PrometeoII/2014/022 and ACOMP/2014/270 projects (Generalitat Valenciana), Ministerio de Economia y Competitividad (Spain), CTQ2012- 36253-C03-02 and the Spanish Brazilian program (PHB2009-0065-PC) for financially supporting this research. We also acknowledge the Servei Informática, Universitat Jaume I for a generous allotment of computer time

A 3D platform for the morphology modulation of materials: first principles calculations on the thermodynamic stability and surface structure of metal oxides: Co3O4, α-Fe2O3, and In2O3

Essentially, the exposed crystal planes of a given material, which primarily determine their morphology, tremendously affect its behavior. First principle calculations, based on the Wulff construction model and broken bonding density index, have been performed to calculate the equilibrium and their transformations for different metal oxides: Co3O4, α-Fe2O3, and In2O3. Present results point out that starting by surface thermodynamics is a helpful approach to predict and assess the morphology transformations of these materials. These complete set of morphologies may serve as a guide for researchers, when analyzing the images from electron microscopies, to gain further understanding of how to control crystal shape synthetically by tuning the surface chemistry and by controlling the relative values of surface energies

PPAR<i>γ</i> agonist-loaded PLGA -PEG nanocarriers as a potential treatment for Alzheimer’s disease: in vitro and in vivo studies

Objective: The first aim of this study was to develop a nanocarrier that could transport the peroxisome proliferator-activated receptor agonist, pioglitazone (PGZ) across brain endothelium and examine the mechanism of nanoparticle transcytosis. The second aim was to determine whether these nanocarriers could successfully treat a mouse model of Alzheimer’s disease (AD). Methods: PGZ-loaded nanoparticles (PGZ-NPs) were synthesized by the solvent displacement technique, following a factorial design using poly (lactic-co-glycolic acid) polyethylene glycol (PLGA-PEG). The transport of the carriers was assessed in vitro, using a human brain endothelial cell line, cytotoxicity assays, fluorescence-tagged nanocarriers, fluorescence-activated cell sorting, confocal and transmission electron microscopy. The effectiveness of the treatment was assessed in APP/PS1 mice in a behavioral assay and by measuring the cortical deposition of β-amyloid. Results: Incorporation of PGZ into the carriers promoted a 50x greater uptake into brain endothelium compared with the free drug and the carriers showed a delayed release profile of PGZ in vitro. In the doses used, the nanocarriers were not toxic for the endothelial cells, nor did they alter the permeability of the blood–brain barrier model. Electron microscopy indicated that the nanocarriers were transported from the apical to the basal surface of the endothelium by vesicular transcytosis. An efficacy test carried out in APP/PS1 transgenic mice showed a reduction of memory deficit in mice chronically treated with PGZ-NPs. Deposition of β-amyloid in the cerebral cortex, measured by immunohistochemistry and image analysis, was correspondingly reduced. Conclusion: PLGA-PEG nanocarriers cross brain endothelium by transcytosis and can be loaded with a pharmaceutical agent to effectively treat a mouse model of AD