Degradation of 14c‐maneb in sediment from a Nicaraguan estuary

Sediment samples were collected at 5 sites in the Nicaraguan estuary “El Naranjo” in July 94 and September 94. The samples were incubated with ¹⁴C‐maneb (0.08 μg.g^‐1 dw sediment), and evolved ¹⁴CO₂ and residual ¹⁴C‐ETU in soil were measured. Mineralization kinetics of ^I4C‐maneb was best described with kinetic models which include growth of microorganisms. The amounts of ¹⁴C‐maneb mineralized were highest at the sites closest to the mouth of the river. No significant differences in degradation between July and September were seen. After 67 days between 9.73 and 16.18% of added ¹⁴C had evolved as ¹⁴CO₂ in the July samples and after 150 days between 11.18 and 27.37% of added ¹⁴C had evolved as ¹⁴CO₂ from the September samples. When 4.61–8.20% of added ^I4C was found in the soil extract, 0.00–2.72% was ¹⁴C‐ETU.     

Development of kinetic models for gas phase MTBE production

Methyl tert-butyl ether (MTBE) synthesis is nowadays carried out using resin catalysts. An alternative zeolitic catalyst is presented in this study. This catalyst presents better mechanical and thermal strength, as well as slightly better performance. It is capable of enduring temperatures that would deactivate resin catalyst. The microkinetic study presented below indicates the importance of temperature and molar feed ratio depending on the catalyst used. Activation energy was found to be 15.7 kcal/g mol. Reaction mechanism suggested involved adsorption of isobutylene on two active sites and methanol on one active site.     

Effect of temperature and concentration in catalytic deactivation of a parallel (competitive) reaction system: Application to hydrotreating of vacuum gas oil

The temperature‐time sequences to maintain constant the concentration of one product in a two‐parallel (competitive) exothermic reaction system undergoing catalyst deactivation are analyzed. Kinetics is described by a power law model and linear particle deactivation. A computational algorithm and a parametric study for adiabatic packed bed reactors are presented. It is found that temperature‐time trajectories are strongly influenced by mean activity, and the selectivity. Experimental information for Hydrotreating of vacuum gas oil was obtained keeping constant desulfurization, while hydrocracking and denitrogenation are function of time. Trajectories and final operating temperature are predicted with error below 2% compared to real operation.     

Towards an ontology modeling tool. A validation in software engineering scenarios

Ontology creation and management related processes are very important to define and develop semantic services. Ontology Engineering is the research field that provides the mechanisms to manage the life cycle of the ontologies. However, the process of building ontologies can be tedious and sometimes exhaustive. OWL-VisMod is a tool designed for developing ontological engineering based on visual analytics conceptual modeling for OWL ontologies life cycle management, supporting both creation and understanding tasks. This paper is devoted to evaluate OWL-VisMod through a set of defined tasks. The same tasks also will be done with the most known tool in Ontology Engineering, Protégé, in order to compare the obtained results and be able to know how is OWL-VisMod perceived for the expert users. The comparison shows that both tools have similar acceptation scores, but OWL-VisMod presents better feelings regarding user’s perception tasks due to the visual analytics influence.     

Autonomous real-time landing site selection for Venus and Titan using Evolutionary Fuzzy Cognitive Maps

Future science-driven landing missions, conceived to collect in situ data on regions of planetary bodies that have the highest potential to yield important scientific discoveries, will require a higher degree of autonomy. The latter includes the ability of the spacecraft to autonomously select the landing site using real-time data acquired during the descent phase. This paper presents the development of an Evolutionary Fuzzy Cognitive Map (E-FCM) model that implements an artificial intelligence system capable of autonomously selecting a landing site with the highest potential for scientific discoveries constrained by the requirement of soft landing in a region with safe terrains. The proposed E-FCM evolves its internal states and interconnections as a function of real-time data collected during the descent phase, therefore improving the decision process as more accurate information becomes available. The E-FCM is constructed using knowledge accumulated by planetary experts and it is tested on scenarios that simulate the decision process during the descent phase toward the Hyndla Regio on Venus. The E-FCM is shown to quickly reach conclusions that are consistent with what would be the choice of a planetary expert if the scientist were presented with the same information. The proposed methodology is fast and efficient and may be suitable for on-board spacecraft implementation and real-time decision making during the course of robotic exploration of the Solar System.     

Optimization of Radial Basis Function neural network employed for prediction of surface roughness in hard turning process using Taguchi’s orthogonal arrays

This work presents a study on the applicability of radial base function (RBF) neural networks for prediction of Roughness Average (R_a) in the turning process of SAE 52100 hardened steel, with the use of Taguchi’s orthogonal arrays as a tool to design parameters of the network. Experiments were conducted with training sets of different sizes to make possible to compare the performance of the best network obtained from each experiment. The following design factors were considered: (i) number of radial units, (ii) algorithm for selection of radial centers and (iii) algorithm for selection of the spread factor of the radial function. Artificial neural networks (ANN) models obtained proved capable to predict surface roughness in accurate, precise and affordable way. Results pointed significant factors for network design have significant influence on network performance for the task proposed. The work concludes that the design of experiments (DOE) methodology constitutes a better approach to the design of RBF networks for roughness prediction than the most common trial and error approach.     

Biofunctional Silk/Neuron Interfaces

Silk fibroin (SF) is a biocompatible and slowly biodegradable material with excellent mechanical properties and huge potential for use as biofunctional interface in electronic devices that aim to stimulate and control neural network activity and peripheral nerve repair. It is shown that SF films act as material interfaces that support the adherence and neurite outgrowth of dorsal root ganglion (DRG) neurons and preserve neuronal functions. Silk films preserve the capability of neuronal cells to fire and DRG neurons on silk films retain the intracellular free Ca²⁺ concentration ([Ca²⁺]_i) response to capsaicin, a typical noxious stimulus for this neuronal culture model. It is also demonstrated that nerve growth factor (NGF)‐functionalized silk films promote neurite outgrowth and modulate functional properties of DRG neurons. The results show that silk preserves DRG neuronal physiology and is a promising biomaterial platform for the future development of devices with goals including functional recovery of injured neurons, neurite functional outgrowth in vitro, or functional electrostimulation in vivo.     

Hydrothermal synthesis and polarized micro-Raman spectroscopy of copper molybdates

Conventional and microwave-assisted hydrothermal methods were used to synthesize Cu₃(MoO₄)₂(OH)₂ ceramics. Different experimental conditions of temperature, time and precipitation rate were employed to explore the growth mechanisms, structural and morphological properties of the obtained copper molybdates. The use of microwave-assisted reactors at 150?°C/10–30?min produced a mixture of copper molybdate hydrates, while only Cu₃(MoO₄)₂(OH)₂ was obtained by using microwave processing at longer times (above 120?min) or conventional hydrothermal reactors (110–250?°C/24?h). Experiments conducted after fast and slow coprecipitation rates resulted in different crystallographic phases and morphologies. Flower-like and rod-like micrometer-sized ceramics were produced with high anisotropy and single-crystalline nature. A better understanding on the growth mechanisms, as well as on the structural and morphological characteristics of copper molybdates was attained. Based upon the relative enhancement of Raman bands in parallel or in perpendicular configuration, a symmetry assignment of 34 (17A_g + 17B_g) external modes for Cu₃(MoO₄)₂(OH)₂ ceramics (42 bands are expected) was possible. Besides, five (of six possible) internal OH-stretching modes were identified in the spectral region above 3200?cm^?1.     

Study of an Annular Photoreactor with Tangential Inlet and Outlet. II. The UV/H2O2 Reactive Flow

The concentration profiles of species involved in the degradation of phenol by an advanced oxidation process (AOP) are modeled by a computational fluid dynamics tool in an annular reactor whose fluid dynamics was the object of a previous study. The reactive flow was fully described together with the radiation field and the kinetic model, which encompasses large kinetic constants such as 10¹⁰ L mol^?1s^?1. Phenol degradation can be simulated by using relaxation factors of at least 10¹² kg m^?3s^?1. The hydroxyl radical concentration profile depends on the radiation field, assessed by the discrete ordinate and the discrete transfer methods. Phenol can be completely degraded along the reactor. A centrifugal effect was observed, with higher concentrations of degradation products along the inner wall at the reactor outlet.     

Proximity to chipboard industries increases the risk of respiratory and irritation symptoms in children: The Viadana study

Emissions related to wood production processes are a recognized health hazard for professionally exposed subjects. The health effects of living close to wood industries are not known, particularly in the pediatric population. We aimed at investigating if living close to chipboard industries is a health hazard for the children in the Viadana district (Northern Italy).In December 2006, all the children (3-14 years) living in the Viadana district, where two big chipboard industries are located, were surveyed through a parental questionnaire (n = 3854). The children were geocoded, and the distance of their houses/schools from the closest wood plant was computed.Independently of sex, age, nationality, residential area, traffic, parents' education, passive/parental smoking, questionnaire compiler and his/her environmental concern, the children living at < 2 km from chipboard industries had a greater prevalence of respiratory (OR = 1.33, 95%CI: 1.11, 1.60), cough/phlegm (OR = 1.43, 95%CI: 1.08, 1.88), nose/throat/mouth (OR = 1.47, 95%CI: 1.23, 1.75), eye (OR = 1.24, 95%CI: 1.04, 1.48) symptoms, school-days lost (OR = 1.24, 95%CI: 1.04, 1.48), and emergency (OR = 2.14, 95%CI: 1.47, 3.11) and hospital (OR = 2.21, 95%CI: 1.17, 4.18) admissions. There was an inverse dose-response relationship between the adverse health outcomes considered and the distance from the plants. The attributable fractions for the children living close to the chipboard industries were substantial, ranging from 13% (eye symptoms) to 27% (cough/phlegm).The present findings suggest that emissions from chipboard industries might have a serious impact on children's health status and should therefore be reduced and closely monitored.