Causal Message Sequence Charts

Scenario languages based on Message Sequence Charts (MSCs) have been widely studied in the last decade. The high expressive power of MSCs renders many basic problems concerning these languages undecidable. However, several of these problems are decidable for languages that possess a behavioral property called “existentially bounded”. Unfortunately, collections of scenarios outside this class are frequently exhibited by systems such as sliding window protocols. We propose here an extension of MSCs called causal Message Sequence Charts and a natural mechanism for defining languages of causal MSCs called causal HMSCs (CaHMSCs). These languages preserve decidable properties without requiring existential bounds. Further, they can model collections of scenarios generated by sliding window protocols. We establish here the basic theory of CaHMSCs as well as the expressive power and complexity of decision procedures for various subclasses of CaHMSCs. We also illustrate the modeling power of our formalism with the help of a realistic example based on the TCP sliding window feature.     

HgCl2 sorption on lignite activated carbon: Analysis of fixed-bed results

Factors that influence kinetic reactivity and equilibrium between elemental mercury, carbon, and flue gas components have been the focus of numerous studies. This study pertains to recent bench-scale fixed-bed tests in which activated carbon was exposed to HgCl₂ in a flue gas composition typical of an unscrubbed eastern bituminous coal. Results are discussed in light of a refined binding site model based on the zigzag carbene structures recently proposed for electronic states at the edges of the carbon graphene layers.     

Space charge in dielectrics. Energy storage and transfer dynamicsfrom atomistic to macroscopic scale

The consequence of the coupling of a charged particle with a polarization field is the formation of a quasi-particle called the `polaron'. The degree of `localization' of such charge depends on the nature of this coupling. In this way, trapping at an atomic scale is described as resulting from the evolution of a coupling involving successively: the electronic polarization field, the infrared polarization field, and the quasi-static ionic polarization field. The internal energy stored in the surrounding medium polarized by the charge is high because the charge is so well localized. The maximum of this energy is obtained for the quasi-static polarization field; its magnitude is of the order of 5 to 10 eV per trapped charge. This work addresses the physics of aging and of the breakdown process on the basis of an unsustainable increase in local internal energy within the material, due to charge trapping-the polarization around a trapped charge increases the local energy; the relaxation of the material lattice then follows a rapid detrapping of charges from their sites, releasing the local excess site region energy into the material. Such a release executes transient virtual work on the material, producing macroscopic dielectric damage, and when critical, unstable conditions are achieved in the time domain, this is followed by electrical breakdown. This interpretation of electrical material breakdown is related to bulk breakdown as observed in thin film laminate structures (~μm) and surface flashover as seen in large structures (~mm to cm)     

Well-defined group IV supported catalysts: An efficient way to increase activities in the deperoxidation of cyclohexyl hydroperoxide with environmentally systems

Silica-supported (SiO)₃MOR (M=Ti, Zr, Hf; R=H, ^tBu) organometallic complexes of group 4, uniform in composition and in distribution, were synthesized via a molecular engineering approach of the construction of active sites. These catalysts were fully characterized by various methods including solid-state NMR, infrared spectroscopy and microanalysis. In the goal to develop environmentally friendly processes,these solids were used as catalysts for the deperoxidation of cyclohexyl hydroperoxide, an important step in the synthesis of adipic acid, a precursor of nylon 6-6.

The best metal is titanium and its performances are far above those of calcined supported titanium catalysts previously reported in the patent litterature. The influence on the catalytic activity of the nature of the coordination sphere and more specifically the number of covalent bonds between titanium and the silica support were studied. The catalysis is mainly heterogeneous as shown by various experiments. A non-negligible amount of titanium is leached during the first stages of the reaction but after some recycles the reaction rate remains constant allowing to suggest that this catalyst should be a good candidate for heterogeneous deperoxidation of cyclohexyl hydroperoxide.     

SIMONE: a realistic neural network simulator to reproduce MEA-based recordings.

Contemporary multielectrode arrays (MEAs) used to record extracellular activity from neural tissues can deliver data at rates on the order of 100 Mbps. Such rates require efficient data compression and/or preprocessing algorithms implemented on an application specific integrated circuit (ASIC) close to the MEA. We present SIMONE (Statistical sIMulation Of Neuronal networks Engine), a versatile simulation tool whose parameters can be either fixed or defined by a probability distribution. We validated our tool by simulating data recorded from the first olfactory relay of an insect. Different key aspects make this tool suitable for testing the robustness and accuracy of neural signal processing algorithms (such as the detection, alignment, and classification of spikes). For instance, most of the parameters can be defined by a probabilistic distribution, then tens of simulations may be obtained from the same scenario. This is especially useful when validating the robustness of the processing algorithm. Moreover, the number of active cells and the exact firing activity of each one of them is perfectly known, which provides an easy way to test accuracy.     

Application of gold catalyst for mercury oxidation by chlorine

This paper discusses a recent study of mercury catalytic oxidation by chlorinating reagents. Gold was chosen as the catalyst because of its reluctance to chemisorb some gases such as O2, NO, H2O, and SO2. This property, as demonstrated in this study, is instrumental to mercury oxidation by circumventing some undesired inhibitory reactions such as OH + NO + M --> HONO + M and OH + SO2 + M --> HOSO2 + M, which were recognized under homogeneous situations at high temperatures. In comparison to Cl2, HCl showed weak oxidizing capability but appreciable inhibition in mercury oxidation by Cl2, probably through the competition of active sites with Cl2. Overall, the mercury catalytic oxidation by Cl2 on gold catalyst surfaces was viable, reaching 40-60% in this study under temperatures of 448-498 K, where the thermal decomposition of formed Hg2+ was effectively avoided.     

Reduction of vibration on a cantilever Timoshenko beam subjected to repeated sequence of excitation with magnetorheological outriggers

This paper deals with the statistical effects of an outrigger system on a cantilever beam under seismic excitation. The nonstationary random approach is employed to simulate seismic events. The Timoshenko beam approach is used to model the frame‐core tube linked at a point of its length by the damped outriggers, therefore are connected vertically two magnetorheological damper devices. The peak root‐mean‐square values of displacement responses is employed as a best measure effective to specify the optimal locations of outriggers according to different vibration modes. To evaluate the performance of the control system, the control algorithm based on Lyapunov stability theory is adopted to seek the input voltage leading to the reduction of vibration.     

An Analysis of Verb Subcategorization Frames in Three Special Language Corpora with a View towards Automatic Term Recognition

Current term recognition algorithms havecentred mostly on the notion of term based onthe assumption that terms are monoreferentialand as such independent of context. Thecharacteristics and behaviour of terms in realtexts are however far removed from this idealbecause factors such as text type orcommunicative situation greatly influence thelinguistic realisation of a concept. Context,therefore, is important for the correctidentification of terms (Dubuc and Lauriston,1997). Based on this assumption, we haveshifted our emphasis from terms towardssurrounding linguistic context, namely verbs,as verbs are considered the central elements inthe sentence. More specifically, we have setout to examine whether verbs and verbal syntaxin particular, could help us towards the taskof automatic term recognition. Our findingssuggest that term occurrence variessignificantly in different argument structuresand different syntactic positions. Additionally, deviant grammatical structureshave proved rich environments for terms. Theanalysis was carried out in three differentspecialised subcorpora in order to explore howthe effectiveness of verbal syntax as apotential indicator of term occurrence can beconstrained by factors such as subject matterand text type.     

Nutrient content of some mushroom species of the genus Termitomyces consumed in Cameroon

The nutrient content (water, lipids, proteins, ashes, crude fibres) of six mushroom species (Termitomyces le Testui, T. aurantiacus, T. schimperi, T. mammformis, T. mboudae?na Mossebo sp. nov., and T. subcypeatus forme bisporus sp. nov.) of the genus Termitomyces from Cameroon was determined. These mushrooms have a high water content (83.3-94.3 g/100 g wet matter) and contain more lipids than species from temperate countries (2.5-5.4 g/100 g dry weight), with high proportions of polyunsaturated fatty acids (45.1-65.1% of total fatty acid methyl esters) and remarkable proportions of crude fibres (17.5-24.7 g/ 100 g dry weight). Their protein content varied between 15.1 and19.1 g/100 g dry weight and ash content between 5.2 and 14.4. The species T. mammiformis was found particularly rich in minerals with 14.4 g ash/ 100 g dry material, that is up to 2.4 g/100 g fresh weight.