A novel sensing platform based on self-doped TiO2 nanotubes for methylene blue dye electrochemical monitoring during its electro-Fenton degradation

Journal of Solid State Electrochemistry - The synthesis of a self-doped TiO2 nanotubes (SD-TNT) electrode and its potential applicability as a sensing platform electrode for voltammetric...     

Evaluation of an Adaptive Resource Allocation for LoRaWAN

Long Range Wide Area Network (LoRaWAN) emerges to connect devices that require long-range and low-cost (bandwidth and power) communication services. In this context, the adoption of this technology brings new challenges due to the densification of IoT devices, which causes signal interference and affects the QoS directly. On the other hand, the LoRaWAN transmission configurations’ flexibility allows higher management to use end-device parameters, allowing better resource utilization and improve network scalability. We evaluate an adaptive solution that defines the best LoRaWAN parameter settings to reduce the channel utilization and, consequently, maximize the number of packets delivered. Additionally, to validate the method, we used a mixed-integer linear programming solution and compared the results obtained with those given by the heuristics. The results achieved by the heuristics were very close to those provided by the optimal result, demonstrating the effectiveness of the heuristics.

     

Mathematical modeling and simulation of inulinase adsorption in expanded bed column

A mathematical model for an expanded bed column was developed to predict breakthrough curves for inulinase adsorption on Streamline SP ion-exchange adsorbent, using a crude fermentative broth with cells as the feedstock. The kinetics and mass transfer parameters were estimated using the PSO (particle swarm optimization) heuristic algorithm. The parameters were estimated for each expansion degree (ED) using three breakthrough curves at initial inulinase concentrations of 65.6 U mL⁻¹. In sequence, the model parameters for an ED of 2.5 were validated using the breakthrough curve at an initial concentration of 114.4 U mL⁻¹. The applicability of the validated model in process optimization was investigated, using the model as a process simulator and experimental design methodology to optimize the column and process efficiencies. The results demonstrated the usefulness of this methodology for expanded bed adsorption processes.     

Morphology,distribution and abundance of antennal sensilla in three stink bug species (Hemiptera: Pentatomidae)

The neotropical stink bugs, Euschistus heros, Piezodorus guildinii and Edessa meditabunda, are important pests of soybean and other crops throughout Central America and in South America from Northern Argentina to Brazil. Mate finding and host plant location in these species depend largely on their chemical communication, and semiochemicals are important mediators of these behaviors. In this study scanning electron microscopy was used to examine the external morphology, distribution and abundance of antennal sensilla on males, females and 5th instar nymphs of these species. Nine morphologically different sensilla types were found: trichod sensilla, type 1 and 2 (ST1 and ST2), long and short basiconic sensilla (SB1, SB2, and SB3), slit-tipped and knob-shaped basiconic sensilla, long chaetic sensilla (Sch) and coeloconic sensilla (Sco). Differences were detected in the abundance and arrangement of the sensilla over the antennal segments in individuals of the same species and among the species studied. The Sch, Sco and the slit-tipped and knob-shaped basiconic sensilla accounted for the major difference in sensilla types among the species. The ST1 was the most abundant type and was restricted to the flagellum. The pedicel of E. heros differs from the pedicels of P. guildinii and E. meditabunda mainly by the absence of Sch. There was a sexual dimorphism in ST1, SB1 and SB2, and this may be an indicative of their roles in detection of male-produced sex pheromone and odors derived from the host plants. The SB2 was lacking in the antennal tip of both sexes and 5th instar nymphs, but was abundant on the second flagellar segment of females of the three species. The same types of sensilla were found on 5th instar nymphs, but always in significantly lower numbers. The morphology and putative functions of each sensilla were compared and discussed.     

The effect of cosurfactants and the initiator concentration on the polymer to surfactant concentration in nanolatexes

The effect of cosurfactant and initiator concentration on the ab initio production of nanolatexes using low surfactant levels was investigated. While the use of cosurfactants (acrylic acid and pentanol) increased the amount of monomer that can be used in styrene‐SDS microemulsion formulations to 13 wt %, high surfactant concentrations are still required, resulting in polymer‐to‐surfactant ratios (Pol/Surf) <1. Latexes with particle size of 30 ± 5 nm were produced upon polymerization of these microemulsions. The Pol/Surf can be significantly increased by increasing the initiator concentration of emulsion polymerization recipes. Particle sizes are comparable with microemulsion latexes, however, less surfactant is required. The reduction in the particle size with higher initiator concentration is attributed to a higher efficiency of particle nucleation and to a higher nucleation rate relative to the rate of monomer transfer. Nanolatexes (particle size < 30 nm) were obtained with 19 wt % solids content and Pol/Surf of 3.6 in ab initio. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Optical properties of B x N y C z monolayers

We apply first-principles methods, based on the density functional theory, to investigate the optical properties of B _x N _y C _z hybrid monolayers containing domains. It is observed that the energy structure of such compounds exhibits bound excitons in the near-infrared region. Moreover, such compounds present an extraordinary absorptive capacity in the visible spectrum, which makes them important candidates for future solar cells applications.     

A study of the carbonation profile of cement pastes by thermogravimetry and its effect on the compressive strength

In a previous work, the authors have carbonated totally high initial strength and sulfate-resistant Portland cement pastes. In order to solve the mechanical problems caused by the intense carbonation that occurred during those experiments, new carbonation conditions were applied in this study. The obtained products were analyzed with respect to the carbonation reactions by thermogravimetry and compressive mechanical strength. Comparative analysis with reference pastes obtained without carbonation at the same age shows that CO₂ capture increases with carbonation time. However, there is an optimum time, up to which the carbonation treatment does not affect the mechanical properties of the paste. Below this time, the lower is the carbonation time the higher is the increase of compressive strength, when compared to that of the reference pastes processed at same operating conditions without carbonation.