Physical and mathematical models of gas‐liquid fluid dynamics in LD converters

Fluid dynamics of gas‐liquid interactions in a LD converter to refine steel was physically and mathematically simulated. Using a water model three cases of gas supply were considered, top blowing, bottom injection and combined process top blowing‐bottom injection. Mixing time in top blowing increases with bath height and the distance between the lance of the gaseous jet and the bath surface. The jet penetration was found to be dependent on the modified Froude number. The unstable and unsteady behaviour of the bath topography, as affected by the gaseous jet, was well simulated through a multiphase momentum transfer model. In top blowing, three zones of liquid splashing were found, penetration with low splash, heavy splash and dimpling with low splash intensity. These zones depend on the gas flow rate and the distance from the lance to the bath surface. During bottom injection mixing times decrease with the number of tuyères, increases of bath height and gas flow rate. In a combined process mixing time decreases considerably due to the recirculating flow formed by the action of the top jet and the submerged jets. When a submerged jet is located just below the top jet the mixing time does not decrease as compared with the separated processes either top blowing or bottom stirring.     

Influential factors on the outer lens color in an industrial injection molding process

The quality and the aspect of outer lens fabricated by an injection molding process are an essential part for the optical properties of vehicular lighting system. This work is accurately addressed to identify the influential factors on the red color of the outer lens made of blends of polycarbonate and acrylonitrile butadiene styrene, which are mixed with a red masterbatch. Seven factors were investigated in this work: masterbatch concentration, mold and nozzle temperatures, holding and packing pressures, and holding and packing times. The main influential factors were found through a design of experiments in a linear approximation. The outer lens's red color is mainly influenced by the masterbatch concentration, the nozzle temperature, holding time, and the holding pressure, in a decreasing order. In contrast, the mold temperature, packing pressure, and packing time are not statically significant in the color appearance.     

Microbial ecology of a lactate-driven dark fermentation process producing hydrogen under carbohydrate-limiting conditions

Despite the high prevalence of lactic acid bacteria in dark fermentation (DF) processes, their ecological role is not yet completely elucidated, preventing their systematic use as “helpers” for hydrogen production. The aim of this study was to investigate the microbial community structure of a lactate-driven DF process that successfully produced hydrogen under carbohydrate-limiting conditions using tequila vinasse as a substrate. Microbial responses to stepwise decreases in hydraulic retention time (HRT) from 24 to 4 h were assessed by using Illumina MiSeq sequencing. HRTs above 12 h and below 6 h led to a lower hydrogen production rate (HPR; 0.2–3.3 L/L-d) and process stability (HPR variations within 25–65%), which were associated with the presence of Acetobacter lovaniensis, Clostridium luticellari, Blautia coccoides, and the high abundance of propionate and lactate. Interestingly, transient conditions from unsteady-to-steady state occurred at an HRT of 12 h, where species richness and evenness decreased remarkably. Accordingly, HRTs between 12 and 6 h resulted in higher HPRs of up to 11.7 ± 0.7 L/L-d with HPR variations of less than 10%, which closely matched with the dominance of Clostridium sp., and butyrate and acetate as the main aqueous products. Overall, the results indicate that the successfulness of exploiting the ‘unwanted’ LAB proliferation through lactate-driven DF processes requires the enrichment of lactate-consuming and hydrogen-producing bacteria, which entails the selection of proper biocatalysts and operating conditions/strategies such as the operation of DF reactors under carbohydrate-limiting conditions and low HRTs.     

Cluster validation in clustering‐based one‐class classification

Reconstruction‐based one‐class classification has shown to be very effective in a number of domains. This approach works by attempting to capture the underlying structure of the normal class, typically, by means of clusters of objects. It has the main disadvantage, however, that one has to indicate the number of clusters in advance, for this yields an efficient way of computing a clustering. In this paper, we introduce a new algorithm, OCKRA++, which achieves a better performance, by enhancing a clustering‐based one‐class ensemble classifier (OCKRA) with a cluster validity index that is used to set the best number of clusters during the classifier's training process. We have thoroughly tested OCKRA++ in a particular domain, namely masquerade detection. For this purpose, we have used the Windows‐Users and ‐Intruder simulation Logs data set repository, which contains 70 different masquerade data sets. We have found that OCKRA++ is currently the algorithm that achieves the best area under the curve, with a significant difference, in masquerade detection using the file system navigation approach.     

Cover Image,Volume 68, Issue 5

The cover image is based on the Research Article Effect of different compatibilizers on environmentally friendly composites from poly(lactic acid) and diatomaceous earth by Angel Aguero et al. DOI: 10.1002/pi.5779 .

     

Nixtamalised flour and tortillas from transgenic maize (Zea mays L.) expressing amarantin: Technological and nutritional properties

Nixtamalised flour from transgenic maize (genetically modified maize with the cDNA of amarantin) and its tortillas were evaluated for some technological and nutritional properties and compared to the commercial brand MASECA^™. Nixtamalised transgenic maize flour (NTMF) showed higher protein content, total colour difference, pH, water solubility index, essential amino acids content and lower Hunter “L” value, water absorption index, resistant starch and retrograded resistant starch than MASECA^™ flour. Tortillas from NTMF had higher protein content (12.64% vs 8.93%, db), essential amino acids content and calculated protein efficiency ratio (C-PER; 2.05 vs 1.04) than tortillas from MASECA^™. Tortillas from both nixtamalised transgenic maize and MASECA^™ flours showed similar sensory properties (puffing and acceptability). The use of transgenic maize for flour and tortilla preparation may have a positive impact on the nutritional status of people from countries where maize is the basic staple food.     

The Effect of Exogenous Jasmonic Acid on Induced Resistance and Productivity in Amaranth (Amaranthus hypochondriacus) Is Influenced by Environmental Conditions

Amaranthus hypochondriacus is a C4 pseudocereal crop capable of producing reasonable grain yields in adverse environmental conditions that limit cereal performance. It accumulates trypsin inhibitors and alpha-amylase inhibitors in seeds and leaves that are considered to act as insect feeding deterrents. Foliar trypsin and alpha-amylase inhibitors also accumulate by treatment with exogenous jasmonic acid (JA) in controlled laboratory conditions. Three field experiments were performed in successive years to test if two nonphytotoxic dosages of JA were capable of inducing inhibitor activity in A. hypochondriacus in agronomical settings, and if this induced response reduced insect herbivory and insect abundance in foliage and seed heads. The performance of JA-treated plants was compared to insecticide-treated plants and untreated controls. The effect of exogenous JA on the foliar levels of six additional putatively defence proteins was also evaluated. Possible adverse effects of JA induction on productivity were evaluated by measuring grain yield, seed protein content, and germination efficiency. The results present a complex pattern and were not consistent from year to year. To some extent, the yearly variability observed could have been consequence of growth under drought versus nondrought conditions. In a drought year, JA-treated plants had lower levels of insect herbivory-derived damage in apical leaves and panicle than control plants, whereas in nondrought years, there was an inconsistent effect on aphids, with no effect on lepidopteran larvae. JA treatments reduced the size of the insect community in seed heads. The effect varied with year. Exogenous JA did not adversely affect productivity, and in the absence of drought stress, the higher dosage enhanced grain yield. Induction of defensive proteins by JA, although sporadic, was more effective in nondrought conditions. The patterns of foliar protein accumulation observed suggest that they may be part of a constitutive, rather than inducible, chemical defense mechanism that is developmentally regulated and critically dependent on the environment. The results emphasize the difficulties that are often encountered when evaluating the performance of chemical elicitors of induced resistance in field settings.     

Antiproliferative activity, cell-cycle dysregulation, and cellular differentiation: salicyl- and catechol-derived acyclic 5-fluorouracil O,N-acetals against breast cancer cells

Herein we report the preparation and biological activity of three compounds with the general formula 1-[2-(5-substituted-2-hydroxybenzyloxy)-1-methoxyethyl]-5-fluorouracil. A catechol-derived compound such as 1-[3-(2-hydroxyphenoxy)-1-methoxypropyl]-5-fluorouracil and two salicyl-derived compounds such as (Z)-1-[4-(2-hydroxyphenyl)-1-methoxybut-3-enyl]-5-fluorouracil [(Z)-11] and its dihydrogenated derivative 1-[4-(2-hydroxyphenyl)-1-methoxybutyl]-5-fluorouracil were prepared to complete the set of six O,N-acetals. The most active compound against the MCF-7 breast cancer cell line was (Z)-11: IC(50)=9.40+/-0.64 microM. Differentiated breast cancer cells generate fat deposits in the cytoplasm. MCF-7 cells treated with (Z)-11 underwent an increase in lipid content relative to control cells after three days of treatment. Our results suggest that there may be significant potential advantages in the use of this new differentiating agent for the treatment of breast cancer.     

Corruptible social agents

Agent‐based virtual simulations of social systems susceptible to corruption (e.g., police agencies) require agents capable of exhibiting corruptible behaviors to achieve realistic simulations and enable the analysis of corruption as a social problem. This paper proposes a formal belief‐desire‐intention framework supported by the functional event calculus and fuzzy logic for modeling corruption based on the integrity level of social agents and the influence of corrupters on them. Corruptible social agents are endowed with beliefs, desires, intentions, and corrupt‐prone plans to achieve their desires. This paper also proposes a fuzzy logic system to define the level of impact of corruption‐related events on the degree of belief in the truth of anti‐corruption factors (e.g., the integrity of the leader of an organization). Moreover, an agent‐based model of corruption supported by the proposed belief‐desire‐intention framework and the fuzzy logic system was devised and implemented. Results obtained from agent‐based simulations are consistent with actual macro‐level patterns of corruption reported in the literature. The simulation results show that (i) the bribery rate increases as more external entities attempt to bribe agents and (ii) the more anti‐corruption factors agents believe to be true, the less prone to perpetrate acts of corruption. Copyright © 2014 John Wiley & Sons, Ltd.