Qualitative Modelling and Analysis of Animal Behaviour

The paper presents the LABAQM system developed for the analysis of laboratory animal behaviours. It is based on qualitative modelling of animal motions. We are dealing with the cognitive phase of the laboratory animal behaviour analysis as a part of the pharmacological experiments. The system is based on the quantitative data from the tracking application and incomplete domain background knowledge. The LABAQM system operates in two main phases: behaviour learning and behaviour analysis. The behaviour learning and behaviour analysis phase are based on symbol sequences, obtained by the transformation of the quantitative data. Behaviour learning phase includes supervised learning procedure, unsupervised learning procedure and their combination. We have shown that the qualitative model of behaviour can be modelled by hidden Markov models. The fusion of supervised and unsupervised learning procedures produces more robust models of characteristic behaviours, which are used in the behaviour analysis phase.     

Induction motor drive based on the stator flux vector control

This paper presents a new torque control algorithm for induction motors, based on the stator flux vector control. For each sampling period, the value of the stator voltage is calculated to keep the stator flux equal to the reference vector, while the stator flux reference vector is calculated to keep the rotor flux amplitude constant at all operating conditions. An improved stator and rotor flux estimation algorithm is proposed, enabling robust and stable operation of the drive, even at low speeds. The induction motor torque is manipulated by variations of the flux angular velocity, enabling drive operation with fixed switching frequency and ripple-free torque in the steady state. The performance of the proposed algorithm is tested through various experimental runs, proving good behavior of the drive in both transient and steady-state operating conditions.     

Extracting information from the molten salt database

Molten salt technology is a catchall phrase that includes some very diverse technologies; electrochemistry, heat transfer, chemical oxidation/reduction baths, and nuclear reactors. All of these technologies are linked by the general characteristics of molten salts that can function as solvents, have good heat-transfer characteristics, function like a fluid, can attain very high temperatures, can conduct electricity, and also may have chemical catalytic properties. The Janz molten salt database is the most comprehensive compilation of property data about molten salts available today and is widely used for both fundamental and applied purposes. Databases are traditionally viewed as “static” documents that are used in a “search and retrieval” mode. These static data can be transformed by informatics and data mining tools into a dynamic dataset for analysis of the properties of the, materials and for making predictions. While this approch has been successful in the chemical and biochemical sciences in searching for and establishing structure-property relationships, it is not widely used in the materials science community. Because the design of the original molten salt database was not oriented toward this informatics goal, it was essential to evaluate this dataset in terms of data mining standards. Two techniques were used—a projection (principal components analysis (PCA)) and a predictive method (partial least squares (PLS))—in conjunction with fundamental knowledge acquired from the long-term practice of molten salt chemistry. This article is based on a presentation made in the symposium entitled “Fourth International Alloy Conference,” which occurred in Kos, Greece, from June 26 to July 1, 2005, and was Sponsored by Engineering Conferences International (ECI) and co-sponsored by Lawrence Livermore National Laboratory and Naval Research Laboratory, United Kingdom.     

Comments on "factors influencing the removal of divalent cations by hydroxyapatite"

Recently, Smiciklas et al. [I. Smiciklas, A. Onjia, S. Raicevi?, Dj. Jana?kovi?, M. Mitri?, J. Hazard. Mater. 152 (2008) 876-884)] have reported on the effect of pH, contact time, initial metal concentration and presence of common competing cations on hydroxyapatite sorption properties towards Pb(2+), Cd(2+), Zn(2+) and Sr(2+) ions. However, application of some experimental procedures and methods, as well as the presentation and interpretation of some data is problematic or erroneous.     

Synthesis of Spherical β-Silicon Carbide Particles by Ultrasonic Spray Pyrolysis

Fine agglomerate-free spherical β-SiC powder was synthesized from a dispersion of colloidal silica, saccharose, and boric acid, by means of an ultrasonic spray pyrolysis method. Droplets of 2.2 μm were formed with an aerosol generator, operated at 2.5 MHz, and carried into a reaction furnace at 900°C with argon. Spherical X-ray amorphous gel particles of 1.1 μm were obtained. β-SiC particles with a mean diameter of 0.79 μm and spherical shape resulted when the SiC gel precursor particles were heated at 1500°C in argon.     

System Dynamics Modeling of Reservoir Operations for Flood Management

There exists a strong need to explore simulation techniques that not only represent complex dynamic systems in a realistic way but also allow the involvement of end users in model development to increase their confidence in the modeling process. System dynamics, a feedback-based object-oriented simulation approach, is presented for modeling reservoir operations. The increased speed of model development, the trust developed in the model due to user participation, the possibility of group model development, and the effective communication of model results are main strengths of this approach. The ease of model modification in response to changes in the system and the ability to perform sensitivity analysis make this approach more attractive compared with systems analysis techniques for modeling reservoir operations. The proposed approach is applied to the Shellmouth reservoir on the Assiniboine River in Canada. Operating rules are developed for high flow∕flood years to minimize flooding. Alternative operating rules are explored by changing reservoir storage allocation and reservoir outflows. Impacts on the flood management capacity of the reservoir are investigated by simulating a gated spillway in addition to an existing unregulated spillway. Sensitivity analysis is performed on the reservoir levels at the start of the flood season and the outflow from the reservoir.     

A Comparison of Some Methods for the Determination of the Degree of Substitution of Carboxymethyl Starch

The degree of substitution (DS) markedly affects the properties of sodium carboxymethyl starch (Na‐CMS). In this work Na‐CMS samples with different DS starting from both potato and corn starch were synthesized in an ethanol/water mixture and their DS was determined using three methods: direct titration of the acid form of the carboxymethyl starch (H‐CMS), Cu salt precipitation and back titration. It was found that direct titration gave smaller DS values, while the Cu salt precipitation method gave higher DS values than the back titration method, which was found to be the most accurate. The values of the DS obtained by these methods were similar for lower DS while for higher values the discrepancy was more pronounced. Under the same experimental conditions the CMS obtained from corn starch had a higher DS than the one obtained from potato starch and on average, the discrepancies between the DS values obtained by the employed analytical methods were smaller for the CMS samples synthesized from corn starch.     

Life Cycle Energy Assessment of biohydrogen production via biogas steam reforming: Case study of biogas plant on a farm in Serbia

The aim of this paper is to demonstrate and to quantify energy flows in a life cycle of biogas to biohydrogen production, starting from feedstock materials via anaerobic digestion, biogas upgrading, biohydrogen production, to the end of biogas system (application of digestate as fertilizer in agriculture). The performance of the biogas plant of Mirotin dairy farm in Serbia has been assessed. According to Life Cycle Energy Assessment approach, results obtained in this study have shown that biohydrogen production via biogas steam reforming has negative energy balance (with ?16,837 GJ). It has also been demonstrated that this process is energy unsustainable in an environmental context. In future analysis it would be necessary to consider the other aspects of sustainability, e.g. the economical and social factors in order to estimate the overall sustainability of the biogas utilization pathways, especially having in mind that the technology of converting biogas to hydrogen is still in the development phase.