Application of WASP model for assessment of water quality for eutrophication control for a reservoir in the Peruvian Andes

Water quality models are important tools for facilitating assessment of the main processes occurring in an aquatic system. To this end, a water quality analysis simulation programme (WASP8) was used to assess the eutrophication process in El Pañe Reservoir. The reservoir has a useful water volume of 99.6 hm³ and is connected to six other reservoirs located in the Chili Basin of the Arequipa Region. El Pañe Reservoir, which is the basin head, has exhibited eutrophication problems since 2014, causing water treatment problems for human consumption and a high probability of cyanotoxin releases from intensive algal blooms. Accordingly, the reservoir was divided into 11 segments, ammonia, nitrate, phosphate, total phosphate, dissolved oxygen, water temperature and chlorophyll‐a being the simulated water quality parameters. The simulations were set in a steady state condition for 3 years from October 2015 to October 2018, subsequently determining aquaculture activity and benthic flux as being meaningful nutrient sources impacting the phytoplankton community. The results of the present study provide necessary evidence of the need to exhaustively quantify both sources in future research, which will aid decision makers in identifying the best management option that can help guarantee the sustainable development of the involved human activities.     

Model-free reinforcement learning from expert demonstrations: a survey

Reinforcement learning from expert demonstrations (RLED) is the intersection of imitation learning with reinforcement learning that seeks to take advantage of these two learning approaches. RLED uses demonstration trajectories to improve sample efficiency in high-dimensional spaces. RLED is a new promising approach to behavioral learning through demonstrations from an expert teacher. RLED considers two possible knowledge sources to guide the reinforcement learning process: prior knowledge and online knowledge. This survey focuses on novel methods for model-free reinforcement learning guided through demonstrations, commonly but not necessarily provided by humans. The methods are analyzed and classified according to the impact of the demonstrations. Challenges, applications, and promising approaches to improve the discussed methods are also discussed.

     

Technical properties of compounded kaolin sample from Griva (Macedonia, Greece)

The purpose of this paper is to establish the possible industrial applications of Griva kaolin. This kaolin comes from the alteration of gabbroic rocks from the Griva area, Macedonia, Greece. Mineralogically, the kaolin is composed mainly of kaolinite associated with vermiculite and plagioclases, and traces of quartz, amphiboles, halloysite and smectites. The kaolin grain-size analysis shows that the kaolin is mostly finer than <20 μm with 20% of <2 μm. The amounts of Fe, Mg and Ca for the < 20 μm fraction are higher than those of standard commercial kaolins. The kaolinite is disordered with low crystallinity. Kaolinite crystals do not present typical pseudohexagonal stackings, showing irregular morphology, and vermicular aggregates booklets. The Brookfield viscosity of about 450 cp (at 70% solids 12 rpm), the high brightness (83% on < 20 μm fraction) and the dispersability in water suspensions would favour its use as filler in the paper and paint industries. However, the low crystallinity kaolinite precludes its use as filler in rubber industry. The kaolin shows a liquid limit of about 48% and a plastic limit of 34%. The firing characteristics indicate its possible use as a ceramic raw material for stoneware and sanitary ware products.     

High temperature proton exchange membrane fuel cell using a sulfonated membrane obtained via H2SO4 treatment of PEEK-WC

A method for the sulfonation of PEEK-WC, a glassy poly(ether ether ketone) with sulphuric acid is presented. Depending on the reaction time, polymers with ion exchange capacity (IEC) from 0.30 to 0.76 meq_H⁺/g are obtained, as determined by titration with NaOH solutions. The thermal properties of the polymers were studied by differential scanning calorimetry, showing that the glass transition temperature increases with increasing degree of sulfonation, from 224 °C for pure PEEK-WC to 246 °C for the polymer having an IEC of 0.76 meq_H⁺/g. The sulfonated polymers were used to prepare proton exchange membranes for possible application in fuel cells. Dense membranes were prepared by solvent evaporation, using DMA as the solvent. The transport properties of the membranes were determined in terms of water uptake and permeability for hydrogen and oxygen. Electrochemical characterization was performed by measuring cell voltage and power density curves as a function of current density at different working temperatures and the results were compared with those of a commercial Nafion membrane. A power density of 284 mW/cm² was obtained for S-PEEK-WC membrane at 120 °C in H₂/air fuel cell, slightly above the corresponding value found for Nafion.     

Hepatic Δ9, Δ6, and Δ5 desaturations in non-insulin-dependent diabetes mellitus eSS rats

Both diabetes mellitus type 1 and diabetes mellitus type 2 are widespread diseases that alter carbohydrate and lipid metabolism. e Stilmann-Salgado (eSS) rats are experimental animals that spontaneously evolve to a state similar to that of young people affected by non-insulin-dependent diabetes mellitus (NIDDM; type 2). Using 6-mon-old eSS rats that, according to the literature [Martinez, S.M., Tarrés, M.C., Montenegro, S, Milo, R., Picena, J.C., Figueroa, N., and Rabasa, S.R. (1988) Spontaneous Diabetes in eSS Rats, Acta Diabetol. Lat. 25, 303–313], had already developed insulin resistance, we investigated the changes evoked on Δ9, Δ6, and Δ5 liver desaturases. The abundance of mRNA and enzymatic activities were measured, as well as the FA composition of liver microsomal lipids. Compared to control rats, the mRNA content and activity of SCD-1 (stearoyl CoA-desaturase, isoform of the Δ9 desaturase) were significantly higher, urase, isoform of the Δ9 desaturase) were significantly higher, whereas the mRNA and activities of Δ6 and Δ5 desaturases were not significantly modified. Correspondingly, the proportion of 18∶1n−9 and the ratios of 18∶1n−9/18∶0 and 16∶1/16∶0 in lipids were significantly increased, whereas the proportion of 20∶4n−6 was unaltered. These effects were found while glycemia was constant or increased. The results are completely opposite those described in insulin-dependent diabetes mellitus (type 1), in which a depression of all the desaturases is found. They suggest that in eSS rats, the activities of the desaturases were not modified by an insulin-resistance effect. Moreover, we suggest that the enhancement of SCD-1 activity might be considered as another typical sign of the NIDDM syndrome, because it has also been found in other animal models of NIDDM, for example, the ones evoked by the sucrose-rich diet and in the Zucker rat.     

Carotenoid composition and vitamin A value of an Argentinian squash (Cucurbita moschata)

The carotenoid composition of butternut squash (Cucurbita moschata) cultivated in the province of Santiago del Estero, Argentina, was determined. The main carotenoids isolated were identified as beta-carotene (beta,beta-carotene), alpha-carotene (beta,epsilon-carotene), and lutein (beta,epsilon-carotene-3,3'-diol) and the minor carotenoids, as phytofluene (7,8,11,12,7',8'-hexahydro-psi,psi-carotene), zeta-carotene (7,8,7',8'-tetrahydro-psi,psi-carotene), neurosporene (7,8-dihydro-psi,psi-carotene), violaxanthin (5,6,5',6'- diepoxy-5,6,5',6'-tetrahydro-beta,beta-carotene-3,3'-diol) and neoxanthin (5,6-epoxy-6,7-didehydro-5,6,5',6'-tetrahydro-beta,beta- carotene-3,5,3'-triol). In some samples, 5,6,5',6'-beta-carotene diepoxide, (5,6,5',6'-diepoxy-5,6,5',6'-tetrahydro-beta,beta-carotene) and flavoxanthin (5,8-epoxy-5,8-dihydro-beta,epsilon-carotene-3,3'-diol) were detected. The presence of cis-isomers of beta,beta-carotene was also detected by HPLC. The vitamin A value obtained was 432 micrograms RE/100 g fresh sample, which indicates that this vegetable is an important source of provitamin A.     

Providing RIA user interfaces with accessibility properties

Rich Internet Applications (RIAs) technologies are challenging the way in which the Web is being developed. However, from the UI accessibility point of view, these technologies pose new challenges that the Web Accessibility Initiative of the W3C is trying to solve through the use of a standard specification for Accessible Rich Internet Applications (WAI-ARIA). Currently, the introduction of properties defined in WAI-ARIA is being done in an ad-hoc manner due to the lack of models, methodologies and tools to support the design of accessible RIA UIs. In this paper we propose a semantic approach to deal with this modeling issue by extending the RUX-Method, a model-based method to build RIA UIs. The approach includes the validation process of the accessibility issues at two different levels: the UI structure and the interactions behavior.     

An analysis of the machinability of ASTM grades 2 and 3 austempered ductile iron

The main goal of this work is to perform an analysis of the machinability of two ASTM grades of ADI, namely 2 and 3. The samples used in this work were cast and austempered according to ASTM standards for the production of grade 2 (G2) and grade 3 (G3) ADI. Characterization was accomplished through tensile and hardness tests, metallography and X-ray diffraction. Machinability was evaluated by analyzing tool life, cutting forces, surface finish and chip characteristics in turning operations. A quick-stop test was also performed in order to verify some mechanical processes during the chip formation and to analyze the shear plane angle. Tool life when machining G2 was 33% lower than G3 (18 min against 26 min), although the latter is a harder material. Abrasion and adhesion were the wear mechanisms observed through SEM images, whereas in other cast irons mainly abrasion is observed. Cutting forces measurements showed that the value of K_c1,1 decreased 19%, from 1448 to 1175 N/mm², for G2 as the depth of cut increased from 2 to 5 mm at a cutting speed of 80 m/min and 18%, from 1501 to 1236 N/mm², for G3. Surface roughness measurements proved that a smoother surface is obtained for both alloys at f = 0.10 mm/rev when using an insert with nose radius 1.6 mm instead of smaller radii. Both alloys presented similar surface quality. All chips observed were segmented.     

A SPH-based particle model for computational microrheology

In this article we present a particle method based on smoothed particle hydrodynamics for microrheology simulations of polymeric fluids. The viscoelasticity of the solvent is modelled via a standard Oldroyd-B model and thermal fluctuations, inherently present at the microscopic scale, are incorporated into the particle framework by application of the GENERIC formalism, ensuring the strict fulfilment of the Fluctuation?CDissipation theorem at the discrete level. Rigid structures of arbitrary shape suspended in the viscoelastic solvent are modelled by freezing SPH particles within a given solid domain and letting them interact with the solvent particles. The rheological properties of the Oldroyd-B fluid, namely frequency-dependent storage and loss moduli, are extracted via macroscopic deterministic simulations under small amplitude oscillatory (SAOS) flow and, alternatively, through standard microrheological simulations of a probe particle suspended in the same Brownian viscoelastic medium, by assuming the validity of a generalized Stokes?CEinstein relation (GSER). We check that good agreement with the analytical theory for the Oldroyd-B model is found in the deterministic SAOS flow over the entire regime of frequencies investigated. Concerning the microrheological measurements, good agreement is observed only up to a maximal frequencies corresponding to time scales considerably larger than the viscous time of the probe particle where the diffusive regime is fully established. At larger investigated frequencies, a crossover between diffusive and ballistic behaviour for the MSD of the probe is observed and validity of the GSER is questionable. The model presented here provides an optimal computational framework to complement experimental observations and to analyse quantitatively the basic assumptions involved in the theory of microrheology.