Influence of Carbon on SOx Emissions from Glass Processing

Carbon reacts with Na₂SO₄ in glass batches, influencing SO _x emissions. To study the role of carbon active surface area (ASA) in the decomposition phenomena, Na₂SO₄ is reacted with three carbons with a wide ASA range. The decomposition behavior was evaluated by thermogravimetric analysis (TGA) and evolved gas analysis via mass spectrometry and Fourier transform infrared spectrometry. Higher carbon ASA yields lower decomposition temperatures. SO _x emissions are realized at temperatures as low as 773 K. Isothermal Na₂SO₄–C decomposition initiates via the nucleation of Na₂S. The rate constants for the nucleation regime are normalized against ASA, yielding an activation energy of 275 kJ/mol for nucleation.     

Raman studies of peroxide formation,decomposition, and reduction on Ba/MgO

Ba/MgO is an active catalyst for the oxidative coupling of methane to form ethane and ethylene. It has been proposed that activation of methane occurs via reaction with peroxide species present at the surface of the catalyst. In the present work, Raman spectroscopy has been used to investigate the formation, decomposition, and reduction of BaO₂ on 4 mol% Ba/MgO. The presence of BaO₂ is evidenced by the presence of a band at 842 cm^–1. The peroxide forms above 300°C but is stable to decomposition at temperatures up to 500°C. Reduction of BaO₂ to BaO proceeds via Ba(OH)₂. BaCO₃ forms when either BaO or BaO₂ is exposed to CO₂. Once formed, BaCO₃ is stable to decomposition in He or O₂ at temperatures up to 500°C. Only BaCO₃ is observed when a mixture of CH₄ and O₂ is passed over the catalyst at 500°C.     

Contribution of Dysregulated DNA Methylation to Autoimmunity

Epigenetic mechanisms, such as DNA methylation, histone modifications, and non-coding RNAs are known regulators of gene expression and genomic stability in cell growth, development, and differentiation. Because epigenetic mechanisms can regulate several immune system elements, epigenetic alterations have been found in several autoimmune diseases. The purpose of this review is to discuss the epigenetic modifications, mainly DNA methylation, involved in autoimmune diseases in which T cells play a significant role. For example, Rheumatoid Arthritis and Systemic Lupus Erythematosus display differential gene methylation, mostly hypomethylated 5′-C-phosphate-G-3′ (CpG) sites that may associate with disease activity. However, a clear association between DNA methylation, gene expression, and disease pathogenesis must be demonstrated. A better understanding of the impact of epigenetic modifications on the onset of autoimmunity will contribute to the design of novel therapeutic approaches for these diseases.     

Investigation of the structure and activity of VOx/CeO2/SiO2 catalysts for methanol oxidation to formaldehyde

The effect of ceria on the partial oxidation of methanol to formaldehyde over VO_x/CeO₂/SiO₂ catalysts was investigated. A two-dimensional layer of ceria on silica was prepared by grafting cerium (IV) t-butoxide (Ce(OC₄H₉)₄) onto high surface area, mesoporous silica, SBA-15, and then calcining the resulting product in air at 773 K. Ce surface concentrations obtained this way ranged from 0.2 to 0.9 Ce nm^?2. Next, V was introduced by grafting VO(OⁱPr)₃ onto CeO₂/SiO₂ in order to achieve a surface concentration of 0.6 V nm^?2. XANES spectra indicate that all of the V is in the 5+ oxidation state and Raman spectra show that vanadia exist as pseudo-tetrahedra bonded to either silica or ceria. Data from Raman spectroscopy and temperature-programmed desorption of adsorbed methanol indicate that with increasing Ce surface density, most of the V becomes associated with the deposited ceria. The turnover frequency for methanol oxidation is nearly two orders of magnitude higher for VO_x/CeO₂/SiO₂ than for VO_x/SiO₂, whereas the apparent activation energy and apparent first-order pre-exponential factor are 17 kcal/mol and 1.4 × 10⁶ mol CH₂O (mol V atm s)^?1, respectively, for VO_x/CeO₂/SiO₂ and 23 kcal/mol and 2.3 × 10⁷ mol CH₂O (mol V atm s)^?1, respectively, for VO_x/SiO₂.     

Short- and long-term learning of job interview with a serious game in virtual reality: influence of eyestrain,stereoscopy, and apparatus

Virtual Reality - Do apparatuses and eyestrain have effects on learning performances and quality of experience? Materials and Methods: 42 participants played a serious game simulating a job...     

Behaviour based on decision matrices for a coordination between agents in a urban traffic simulation

This paper describes a multi-agent coordination mechanism applied to intersection simulation situations. In a goal of urban traffic simulation, we must consider the dynamic interactions between autonomous vehicles. The field of multi-agent systems provides us some studies for such systems, in particular on the coordination mechanisms. Conflicts between vehicles (i.e. agents) are very frequent in such applications, and they may cause deadlocks, particularly at intersections such as crossroads. Our approach is based on the solving of two player games/decision matrices which characterize three basic situations. An aggregation method generalizes to n-player games for complex crossroads. The objective of this approach consists in searching basic two-player matrices for solving n-agent problems. To explain the principle, we describe our approach for a particular case of crossroad with three agents. Finally, the obtained results have been examined via a tool of road traffic simulation, ARCHISIM. We assume also that the global traffic replicates the behavior of agents in different situations.     

Switching model predictive attitude control for a quadrotor helicopter subject to atmospheric disturbances

In this article a switching model predictive attitude controller for an unmanned quadrotor helicopter subject to atmospheric disturbances is presented. The proposed control scheme is computed based on a piecewise affine (PWA) model of the quadrotor's attitude dynamics, where the effects of the atmospheric turbulence are taken into consideration as additive disturbances. The switchings among the PWA models are ruled by the rate of the rotation angles and for each PWA system a corresponding model predictive controller is computed. The suggested algorithm is verified in experimental studies in the execution of sudden maneuvers subject to forcible wind disturbances. The quadrotor rejects the induced wind disturbances while performing accurate attitude tracking.     

Flying over the reality gap: From simulated to real indoor airships

Because of their ability to naturally float in the air, indoor airships (often called blimps) constitute an appealing platform for research in aerial robotics. However, when confronted to long lasting experiments such as those involving learning or evolutionary techniques, blimps present the disadvantage that they cannot be linked to external power sources and tend to have little mechanical resistance due to their low weight budget. One solution to this problem is to use a realistic flight simulator, which can also significantly reduce experimental duration by running faster than real time. This requires an efficient physical dynamic modelling and parameter identification procedure, which are complicated to develop and usually rely on costly facilities such as wind tunnels. In this paper, we present a simple and efficient physics-based dynamic modelling of indoor airships including a pragmatic methodology for parameter identification without the need for complex or costly test facilities. Our approach is tested with an existing blimp in a vision-based navigation task. Neuronal controllers are evolved in simulation to map visual input into motor commands in order to steer the flying robot forward as fast as possible while avoiding collisions. After evolution, the best individuals are successfully transferred to the physical blimp, which experimentally demonstrates the efficiency of the proposed approach. Jean-Christophe Zufferey and Alexis Guanella contributed equally to this work.