Texture prediction of Bi2Te3 electroplated layers using Hartman's theory of crystal growth

An experimental study of electroplated thin films of bismuth telluride, R3m crystal structure, shows that fibre textures are observed during the growth of the layers. Several orientations 00.1, 10.10, 11.0, 10.4, 10.8, 01.5 and 10.0 are developed during the deposition process, then reach a final orientation. Hartman's theory of crystal growth based on the periodic bond chain (PBC) in a crystal lattice is usually applied. This explains the equilibrium shape of a crystal defined by F faces and the faces observed during the growth (S and K faces). It also successfully predicts the orientations observed in bismuth telluride from the beginning to the end of the layer deposition. The theory may also be applied to other deposition processes.     

Development of a molecular method for the rapid discrimination of red seaweeds used for agar production

In Tunisia, agar is produced from the species Gracilaria verrucosa. Other species, such as Gracilariopsis sp. which have a very similar morphology to Gracilaria, can be harvested in a mixture with Gracilaria with the result that the quantity and quality of agar extracted is different than initially expected. In this study, we tested the use of ITS sequences from 5.8s rDNA for species discrimination between G. verrucosa and Gracilariopsis harvested from two production sites (Bizerte and Tunis Lagoons). The amplification of genomic ITS sequences and sequencing shows that the samples collected from Tunis can be identified by PCR fragment of 1124 bp whereas the samples from Bizerte are characterized by the presence of two fragments of 1124 and 983 bp, respectively. A BLAST investigation in Genbank shows that the sequence similarities between the fragment of 1124 pb and G. verrucosa was 85% and between the fragment of 983 pb and Gracilariopsis sp. Plymoutn was 94%. Gracilariopsis sp. possesses a PCR fragment with a length of 983 bp, which discriminates it from G. verrucosa when these two species are collected in a mixture as in the lagoon of Bizerte. The RFLP method after EcoRI application provides a characteristic pattern for G. verrucosa, which is composed of two main fragments with respective sizes of 823 and 301 bp whereas amplified DNA of Gracilariopsis was uncut under these conditions.     

Bayesian Robot Programming

We propose a new method to program robots based on Bayesian inference and learning. It is called BRP for Bayesian Robot Programming. The capacities of this programming method are demonstrated through a succession of increasingly complex experiments. Starting from the learning of simple reactive behaviors, we present instances of behavior combination, sensor fusion, hierarchical behavior composition, situation recognition and temporal sequencing. This series of experiments comprises the steps in the incremental development of a complex robot program. The advantages and drawbacks of BRP are discussed along with these different experiments and summed up as a conclusion. These different robotics programs may be seen as an illustration of probabilistic programming applicable whenever one must deal with problems based on uncertain or incomplete knowledge. The scope of possible applications is obviously much broader than robotics.     

Incremental learning of Bayesian sensorimotor models: from low-level behaviours to large-scale structure of the environment

This paper concerns the incremental learning of hierarchies of representations of space in artificial or natural cognitive systems. We propose a mathematical formalism for defining space representations (Bayesian Maps) and modelling their interaction in hierarchies of representations (sensorimotor interaction operator).

We illustrate our formalism with a robotic experiment. Starting from a model based on the proximity to obstacles, we learn a new one related to the direction of the light source. It provides new behaviours, like phototaxis and photophobia. We then combine these two maps so as to identify parts of the environment where the way the two modalities interact is recognisable. This classification is a basis for learning a higher level of abstraction map that describes the large-scale structure of the environment.

In the final model, the perception–action cycle is modelled by a hierarchy of sensorimotor models of increasing time and space scales, which provide navigation strategies of increasing complexities.     

Highly precise experimental device for determining the heat capacity of liquids under pressure

An experimental device for making isobaric heat capacity measurements of liquids under pressure is presented. The device is an adaptation of the Setaram micro-DSC II atmospheric-pressure microcalorimeter, including modifications of vessels and a pressure line allowing the pressure in the measurement system to be set, controlled, and stabilized. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very accurate heat capacity measurements under pressure to be made. The relative uncertainty in the isobaric molar heat capacity measurements provided by the new device is estimated to be 0.08% at atmospheric pressure and 0.2% at higher levels. The device was validated from isobaric molar heat capacity measurements for hexane, nonane, decane, undecane, dodecane, and tridecane, all of which were highly consistent with reported data. It also possesses a high sensitivity as reflected in its response to changes in excess isobaric molar heat capacity with pressure, which were examined in this work for the first time by making heat capacity measurements throughout the composition range of the 1-hexanol+n-hexane system. Finally, preliminary measurements at several pressures near the critical conditions for the nitromethane+2-butanol binary system were made that testify to the usefulness of the proposed device for studying critical phenomena in liquids under pressure.     

Composition and antimalarial activity in vitro of volatile components of Lippia multiflora

The essential oil of Lippia multiflora was prepared by hydrodistillation of leaves and stalks and characterized by GC and mass spectroscopy. The oil was tested for antimalarial activity on in vitro cultures of Plasmodium falciparum (FcB1-Columbia chloroquine-resistant strain and F32-Tanzania chloroquine-sensitive strain). The dilutions inhibiting the in vitro growth of the parasite by 50% 24 and 72 hr after administration of the essential oil to the parasite culture were 1/12,000 and 1/21,000, respectively. When tested on a highly synchronized culture, the essential oil inhibited growth mostly at the trophozoite-schizont step, indicating a potential effect on the first nuclear division of the parasite.     

Structural study by 1H NMR of the first adducts of the telomerization of methylmethacrylate with thiophenol

The stereoselectivity of the different steps (addition step and transfer step) of the radical telomerization of methylmethacrylate with thiophenol has been determined by preparing and analyzing the first adducts by ¹H NMR analysis.     

Measured versus simulated transient disturbances induced on asystem harness

The increasing complexity of electronic payloads on satellites and aircraft has resulted in an increase in electromagnetic compatibility (EMC) test campaign costs and duration. Affordable simulation tools can help system engineers to reduce costs and prevent damage during tests. A method of moments (MOM) based simulation tool for the analysis of electrostatic discharge (ESD) interactions with systems has been assessed. Comparisons between experimental and simulated results are reported together with the adopted setup modeling philosophy. The results showed a very good performance of the simulation tool and the need to characterize and include in the computation the experimental current probe model     

Alternating anoxic feast/aerobic famine condition for improving granular sludge formation in sequencing batch airlift reactor at reduced aeration rate

In this study the influence of a pre-anoxic feast period on granular sludge formation in a sequencing batch airlift reactor is evaluated. Whereas a purely aerobic SBR was operated as a reference (reactor R2), another reactor (R1) was run with a reduced aeration rate and an alternating anoxic-aerobic cycle reinforced by nitrate feeding. The presence of pre-anoxic phase clearly improved the densification of aggregates and allowed granular sludge formation at reduced air flow rate (superficial air velocity (SAV) = 0.63 cm s⁻¹). A low sludge volume index (SVI₃₀ = 45 mL g⁻¹) and a high MLSS concentration (9–10 g L⁻¹) were obtained in the anoxic/aerobic system compared to more conventional results for the aerobic reactor. A granular sludge was observed in the anoxic/aerobic system whilst only flocs were observed in the aerobic reference even when operated at a high aeration rate (SAV = 2.83 cm s⁻¹). Nitrification was maintained efficiently in the anoxic/aerobic system even when organic loading rate (OLR) was increased up to 2.8 kg COD m⁻³ d⁻¹. In the contrary nitrification was unstable in the aerobic system and dropped at high OLR due to competition between autotrophic and heterotrophic growth. The presence of a pre-anoxic period positively affected granulation process via different mechanisms: enhancing heterotrophic growth/storage deeper in the internal anoxic layer of granule, reducing the competition between autotrophic and heterotrophic growth. These processes help to develop dense granular sludge at a moderate aeration rate. This tends to confirm that oxygen transfer is the most limiting factor for granulation at reduced aeration. Hence the use of an alternative electron acceptor (nitrate or nitrite) should be encouraged during feast period for reducing energy demand of the granular sludge process.