BUSINESS EXCELLENCE IN PUBLIC-UTILITY COMPANIES BY INNOVATIVENESS BASED ON DIALECTICAL SYSTEMS THINKING

Bertalanffian systemic thinking attacks over-specialization and tries to teach humans how to attain holism for humankind to survive. Indirect ways may support this crucial intention better, including business excellence, which enjoys the support of, for example, the European Quality Award (EFQM/EQA). But in some industries, such as public utilities working on waste problems, market and EFQM/EQA do not support systemic thinking well enough. The new model presented herein has been evolving for over ten years and has proven successful in practice in the public utility companies.     

Non-local stabilization of a spherical inverted pendulum

We design a non-linear stabilizing control law for a four degree of freedom spherical inverted pendulum. The pendulum is a slim cylindrical beam attached to a horizontal plane via a universal joint; the joint is free to move in the plane under the influence of a planar force. The upright position is an unstable equilibrium of the uncontrolled system because of gravity. The objective is to design a controller so that it stabilizes the upright position starting from any position in the upper hemisphere with arbitrary velocity. We achieve this by first transforming the original system to an appropriate upper triangular form and then designing a controller which incorporates a high gain design with the method of non-linear forwarding. The control law is evaluated through computer simulations.     

Apparent fracture toughness of low-carbon steel CSN 411353 as related to stress corrosion cracks

The occurrence of cracks in structural components indicates a certain threat to their reliable operation, because these cracks can grow during operation and reach critical sizes, leading to fracture. The fracture resistance of a structural component is given by the fracture toughness of the material, determined on standardized specimens with a precycled fatigue crack, and the constraint. The fracture toughness itself depends also on the environment. There is enough evidence that in the conditions of the environment assisted cracking the fracture toughness can be significantly reduced by hydrogen mechanism. Our research results have confirmed this and have demonstrated a considerable reduction in the stress corrosion fracture toughness as compared to that related to fatigue cracks. This should be taken into account when assessing the integrity of structural components with stress corrosion cracks. This paper presents experimental results concerned with the stress corrosion fracture toughness of specimens from a DN150 gas line pipe made of low-C steel CSN 411353.     

Influence of solvent and temperature on extraction of phenolic compounds from grape seed,antioxidant activity and colour of extract

This study was aimed to investigate the influence of solvent (water and ethanol in concentration: 50%, 70% and 96%) and extraction temperature (25–80) °C on polyphenols extraction of grape seed (Vitis vinifera L. cv. “Frankovka”) cultivated in Eastern Croatia. The best results were reached using 50% ethanol at 80 °C. The most abundant individual polyphenolic compound was catechin which makes the average of 45.11% of the total phenolic content followed by epicatechin (34.45%), procyanidin B₂ (12.90%), gallic acid (5.34%), gallocatechin (1.58%), epicatechin gallate (1.01%). The antioxidant activity of extracts was determined by DPPH‐method and it was highly dependent on extraction solvent and temperature. The total extractable proanthocyanidins content of extract had the highest positive correlation (r = 0.994) with antioxidant activity, which indicated that these compounds might be the most important antioxidant in examined grape seed extracts. Relationship between phenolic content and colour of extracts was observed.     

An analysis of segregation-induced changes in grain boundary cohesion in bcc iron

We thoroughly compare available experimental as well as theoretical values of the strengthening/embrittling energy of numerous solutes at grain boundaries in α-iron and assess their reliability. The strengthening/embrittling energy is displayed according to its relationship to the difference of corresponding sublimation enthalpies of the host and the solute as well as with regard to the position of the solute in the Periodic Table.     

High‐Pressure Generator of Singlet Oxygen

The generation of gaseous singlet oxygen by gas‐liquid reaction of chlorine with alkaline solution of hydrogen peroxide in spray form was studied experimentally on the originally designed device with a fast separation of reacted liquid from gas. The singlet oxygen yield, residual chlorine, and water vapor content in gas were measured under different experimental conditions of the centrifugal spray singlet oxygen generator (CSSOG) using nitrogen as a dilution gas. A characteristic feature of the CSSOG is a high utilization of the chemicals and production of singlet oxygen at a very high total pressure even near the atmospheric pressure. This generator developed originally for driving a chemical oxygen‐iodine laser (COIL) could be employed also as an efficient singlet oxygen source in material science, chemical synthesis, and others.     

Thermodynamics of Nitric Acid Extraction with Iso-Butanol. I. Water Activity In Iso-Butanol

A numerical procedure was employed to evaluate hydrated water attached to the extractable nitric acid/iso-butanol complex. The hydratation number was found to be 11, a value favourable in comparison to the hydratation numbers published for straight chain alcohols extractants. Of several tested approaches, the fourth order interaction Scatchard equation offers water activity coefficients in the alcohol phase which are in close agreement with the measured ones.     

Functional adaptive controller for multivariable stochastic systems with dynamic structure of neural network

The article deals with a challenging problem of adaptive control design for multivariable stochastic systems with a functional uncertainty. Model of the system is based on multi‐layered perceptron neural networks where both the unknown parameters and the structure are found in real time without a necessity of any off‐line training process. The unknown parameters are estimated by a global estimation method, the Gaussian sum filter, and the structure of the neural network model is optimized by a proposed pruning method. The control law is based on a bicriterial approach to the suboptimal dual control. Two individual criteria are designed and used to introduce conflicting efforts between the estimation and control; probing and caution. A comparison of the proposed dual control and its alternative with an implementation of the pruning algorithm is shown in a numerical example. Copyright © 2011 John Wiley & Sons, Ltd.