Performance evaluation of complementary code combining diversity in DVB-SH

In this paper, the application of code combining diversity in Digital Video Broadcasting Satellite to Handheld (DVB-SH) systems is analyzed. The complementary code combining diversity is a simple and efficient technique that exploits the advantages of a hybrid satellite/terrestrial system. A meaningful diversity gain can be obtained in multiple frequency networks, allowing an improvement of the receiver robustness in both static and mobile scenarios. Furthermore, for typical DVB-SH terminals with two receiver branches, this gain can be easily obtained without increasing the hardware complexity.     

A rigorous computational model for hydrogen production from bio-ethanol to feed a fuel cell stack

A pseudo dynamic rigorous model of a bio-ethanol processor system (BPS) to produce hydrogen for feeding a Proton Exchange Membrane Fuel Cell (PEM-FC) is presented. The main contribution of this work is to give the overall set of differential and algebraic equations (DAE), assumptions and the way to computationally implement it. This model is able for testing the dynamic behavior of this integrated process, obtaining a reduced order linear model and checking any plant-wide control structure design. It is implemented in two programs, HYSYS and MATLAB, properly communicated to coordinate the calculations performed on each one. A part of the process considered with a faster dynamic than the rest of the units of the plant are simulated in HYSYS environment working in steady state mode. Then, auxiliary equipments and the heat exchangers network are in HYSYS which is called by MATLAB every integration interval for doing the simulation of the complete system. On the other side, the PEM-FC and the dynamic models of the plug flow reactors are developed in MATLAB workspace. Hence, strictly speaking this model must be considered as “pseudo” dynamic. The linearized and reduced order model is developed by applying system identification techniques on the rigorous model. Therefore, accounting the main objectives of the process and the most critical disturbances, a preliminary control structure can be well-tested here. Several results are presented in this work analyzing the obtained performances for opened and closed loop modes.     

Electrochemical peroxidation using iron nanoparticles and anodic iron dissolution to remove selenium from oil refinery wastewater

Experimental results for selenium removal from oil refinery wastewater applying the electrochemical peroxidation process (ECP) using either graphite electrodes with iron nanoparticles (nZVI) or carbon steel electrodes with anodic iron dissolution (AD) on laboratory scale are presented. Operating parameters were: current density, iron‐selenium molar ratio and treatment time. It was found that when applying ECP and nZVI, selenium removal reached 93%. On the contrary, when the ECP and AD process was applied, selenium removal only reached 64%. Therefore, the ECP process and use of iron nanoparticles could be a feasible technology to remove selenium from oil refinery wastewater.     

Increasing the separation of block cryoconcentration through a novel centrifugal filter-based method

The objective of this work was to evaluate the filter addition in centrifugal cryoconcentration. The cryoconcentration process was optimized by Response Surface Method using initial concentration (C₀) and centrifugation speed (CS) (independent variables) and efficiency (η), percentage of concentrate (PC) and solute yield (Y) (dependent variables), under radial and axial freezing conditions. The optimal interactions were 5 (wt.%), 3850 rpm and axial condition, with high final solute concentration, and extraordinary separation, with 86%, 63% and 0.87 (kg/kg) for η, PC and Y, respectively. Therefore, the centrifugal filter cryoconcentration allowed the migration of solutes between the crystals, and the filter improved the separation and elution process of the concentrated solution from the ice.     

A new approach for three-phase loads compensation based on the instantaneous reactive power theory

The original instantaneous reactive power theory or p–q theory has been systematically used in the control of active power filters (APFs). When the APF is connected in parallel to a non-linear and unbalanced load, the p–q theory application has allowed a compensation strategy named constant power to be obtained. This means that, after the APF connection, the instantaneous power supplied by the source is constant and it has the same value as the average power consumed by the load. Nevertheless, the use of other compensation strategies is possible: unity power factor or sinusoidal and balanced supply currents, among others. This paper shows that any compensation strategy may be developed into the p–q theory frame. Besides, the paper presents a p–q theory reformulation without using mapping matrices, which makes easier the obtention of the compensation currents. Finally, an exhaustive analysis of practical cases has been carried out at simulation and experimental level through a laboratory prototype which has allowed the proposed approach to be verified.     

Effect of molecular structures on static and dynamic compression properties of clay and amphiphilic clay/carbon nanofibers used as fillers in UHMWPE/composites for high-energy-impact loading

Three different ultrahigh-molecular-weight polyethylene (UHMWPE)–clay nanocomposites (Muscovite, Cloisite 30B and amphiphilic clay/carbon nanofibers) were investigated with the nanocomposite nanomorphology studied before and after dynamic mechanical compressive tests at high strain rates. Their material structure and thermal properties were investigated using techniques such as step-scan differential scanning calorimetry, split Hopkinson pressure bar, synchrotron small angle X-ray scattering (SAXS), and dynamic mechanical analysis. Results were associated with morphological changes observed after deformation. chemical vapor deposition (CVD)-modified nanocomposite, due to the molecular bonding and the extra functional groups, is designed with crystalline structures with fewer defects and higher stability. The increase in particulate/polymer interactions observed for the CVD-modified material decreased the elongation in the quasi-static test. However, the dynamic mechanical behavior contradicted the quasi-static behavior because at very high strain rates there was not sufficient time for the interlamellar and intralamellar defect facilitated plastic flow and the material transitioned through the glassy state. The SAXS results show that deformation strongly induced changes in the UHMWPE and UHMWPE–clay nanocomposite morphology. SAXS indicates that CVD-modified samples became more compact and dense, thus corroborating the formation of additional secondary bonds between structures and/or the carbon nanofibers alignment. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47094.     

Novel Risk Associations between microRNA Polymorphisms and Gastric Cancer in a Chilean Population

Gastric cancer (GC) is the fifth leading cause of cancer deaths in the world, with variations across geographical regions and ethnicities. Emerging evidence indicates that miRNA expression is dysregulated in GC and its polymorphisms may contribute to these variations, which has yet to be explored in Latin American populations. In a case-control study of 310 GC patients and 311 healthy donors from Chile, we assessed the association of 279 polymorphisms in 242 miRNA genes. Two novel polymorphisms were found to be associated with GC: rs4822739:C>G (miR-548j) and rs701213:T>C (miR-4427). Additionally, rs1553867776:T>TCCCCA (miR-4274) and rs12416605:C>T (miR-938) were associated with intestinal-type GC, and rs4822739:C>G (miR-548j) and rs1439619:T>G (miR-3175) with TNM I-II stage. The polymorphisms rs6149511:T> TGAAGGGCTCCA (miR-6891), rs404337:G>A (miR-8084), and rs1439619:T>G (miR-3175) were identified among H.pylori-infected GC patients and rs7500280:T>C (miR-4719) and rs1439619:T>G (miR-3175) were found among H. pylori cagPAI+ infected GC cases. Prediction analysis suggests that seven polymorphisms could alter the secondary structure of the miRNA, and the other one is located in the seed region of miR-938. Targets of miRNAs are enriched in GC pathways, suggesting a possible biological effect. In this study, we identified seven novel associations and replicated one previously described in Caucasian population. These findings contribute to the understanding of miRNA genetic polymorphisms in the GC pathogenesis.     

Development of active cassava starch cellulose nanofiber-based films incorporated with natural antimicrobial tea tree essential oil

In the present study, a cassava starch-glycerol film with reinforcement of Pinus sp. nanofibers (NFC) incorporated with tea tree (Melaleuca alternifolia) essential oil (TTO) were prepared by casting technique. The physical (barrier, mechanical, and optical), structural, and antimicrobial properties of the films were evaluated and compared with the control films. Films with 0.08% TTO exhibited a significant increase in the tensile strength (TS) while films with 1.5% TTO showed a decrease in TS, suggesting a crosslinking effect. The addition of 1.5% TTO reduced the water vapor permeability values in 43% comparing to the control films. Analysis obtained by Fourier transform infrared spectroscopy showed bands related to the interaction between TTO and matrix for films with 1.5% TTO and 0.3% NFC. This film was effective against Staphylococcus aureus and Candida albicans which could be applied for several packaging purposes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48726.     

Protein content of grains of different size fractions in malting barley

The negative relationship between grain size (percentage >2.5 mm) and protein content usually observed in barley grain samples is attributed to the presence of thin grains. The objective of this study was to determine whether, in grain samples from a given environment, thin grains had a different protein content than plump grains. Grain samples from field experiments were analysed for grain yield, size and protein content of the whole sample and of four size fractions within each sample. Grain yield ranged from 1.5 to 6.5 mg ha^?1 and grain protein (whole sample) ranged from 6.8 to 13.4 %. Most of the variation observed in protein content was explained by the ratio of nitrogen availability to grain yield. Within a grain sample, thin grains had more protein than plump grains (>2.5 mm) only when the protein content of the whole sample was high, that is, when the grain sample came from an environment with a high relative abundance of nitrogen. The fact that grain samples with low grain size tend to have high protein content is not due to the presence of a high proportion of thin grains, because thin grains do not always have more protein than plump grains. Copyright © 2014 The Institute of Brewing & Distilling