Assessment of a Flexible Architecture for Distributed Control*

Production pipelines of manufactory industries present several machines and robots in which the movements of interpolated axes are managed by computerized numerical controls (CNCs). These are typically synchronized with several other simpler actuators along the pipeline of production. CNCs have to be flexible, easily expandable, and reusable, when pipelines of production are frequently reconfigured to realize different arranged pipelines with different technical requirements. In this paper, the assessment of a flexible CNC for such reconfigurable pipelines is presented. The analysis has been focused on defining objective metrics that can be applied for assessing performance and feasibility of distributed controls for pipelines. The method proposed has been applied on the distributed control architecture defined in the MUPAAC ESPRIT HPCN (Multi Processor Architecture for Automatic Control, High Performance Computer Networking of the European Commission). MUPAAC architecture and prototype has been assessed in order to identify the critical configurations and the limits of the architecture.     

Life cycle cost analysis of alternative vehicles and fuels in Thailand

High crude oil prices and pollution problems have drawn attention to alternative vehicle technologies and fuels for the transportation sector. The question is: What are the benefits/costs of these technologies for society? To answer this question in a quantitative way, a web-based model (http://vehiclesandfuels.memebot.com) has been developed to calculate the societal life cycle costs, the consumer life cycle costs and the tax for different vehicle technologies. By comparing these costs it is possible to draw conclusions about the social benefit and the related tax structure. The model should help to guide decisions toward optimality, which refers to maximum social benefit. The model was applied to the case of Thailand. The life cycle cost of 13 different alternative vehicle technologies in Thailand have been calculated and the tax structure analyzed.     

Physicochemical principles of preparation of emulsion fuels

The basic physicochemical principles of preparation of emulsion fuel compositions based on heavy and extra-heavy crude cuts were analyzed with consideration of the nature and content of the phases constituting the emulsion, type of chemical additives — emulsifiers and stabilizers, and type of equipment for production of emulsion fuels. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 5, pp. 51–56, September–October, 2007.     

Generation of Gas Discharge Plasma by an Arc Source with a Cold Hollow Cathode

The results from a study of an arc plasma source with a cold hollow cathode are presented. The source generates plasma with a density of ∼10¹⁰ cm⁻³ in a volume of ∼0.2 m³ at discharge currents of up to 150 A, an arc discharge operating voltage of 30–40 V, and a low pressure of 0.1–1 Pa. The motion of the cathode spot in the crossed electric and magnetic fields inside the hollow cathode and the cathode’s special design make it possible to eliminate almost completely the penetration of the sputtered cathode material into the working vacuum chamber.__________Translated from Pribory i Tekhnika Eksperimenta, No. 3, 2005, pp. 62–66.Original Russian Text Copyright © 2005 by Schanin, Koval, Akhmadeev.     

Clay compaction modelling by homogenization theory

The modelling of hydromechanical behavior of clayey sediments by homogenization theory is described. The rheological model of clays buried in depth requires a three-dimensional approach and laboratory experiments to quantify the model parameters. An iterative process which can be coupled to any homogenization method is used to model the porous media behavior. Hydromechanical compaction results from oedometric experiments are simulated with the proposed model.     

Influence of generator load conditions on third-harmonic voltages in generator stator winding

The influence of changes in load conditions of the generator-transformer unit on the operating conditions of the 100% ground-fault protection of the generator stator winding based on the third-harmonic voltages was analyzed. The analyzed stator ground-fault protection system is by ratio of the voltages third harmonic in generator neutral and at the generator terminals. The third-harmonic voltages were determined on the base of the experimental tests (measurements) run in real conditions at changes in active and reactive load conditions of the generator. It was found that mainly the generator active load influences the voltage feeding the measuring element of ground-fault protection. Therefore, determining operating conditions of ground-fault protection the influence of the generator active and reactive load should be deeply considered. This can ensure the proper operation of the ground-fault protection based on the voltage third harmonics in the whole range of the changes in generator load. Considering the influence of changes in generator load on the third-harmonic voltages (feeding measuring element of the protection system) will allow eliminating irregular generator tripping as a result of unselective operation of these protections.     

Standby power system VRLA battery reserve life estimation scheme

This paper presents a valve-regulated lead acid (VRLA) battery reserve life estimation scheme. The scheme is adaptive in both type and frequency of involvement. The scheme is based on capacity trending with the support of a number of state-of-health (SOH) indicators. These SOH indicators include accumulated thermal stress, float voltage, and indicators acquired from the start-of-discharge (coup de fouet) region. An implementation test case is given, indicating that the scheme is capable of providing an accurate estimation of reserve life long before the end of life. Furthermore, the estimation accuracy improves as the end of battery life approaches.     

Robust autoregressive predictive power control method for mobile CDMA systems

A closed-loop power control (CLPC) scheme with a multistep (indicating multiple prediction steps) linear autoregressive predictor is presented. The proposed CLPC relies on low-rate sample vector based autoregressive prediction. Compared to currently available predictive CLCP schemes, it demonstrates particularly robust performance in the presence of large loop delays and channel estimation errors.