TS-based sampled-data model predictive controller for continuous-time nonlinear systems

This paper proposes a new fuzzy model predictive control approach for continuous-time nonlinear systems in terms of linear matrix inequalities (LMIs). The proposed approach is based on the Takagi–Sugeno fuzzy modeling, a quadratic Lyapunov function, and a sampled-data parallel distributed compensation controller with constant sampling time. The goal is designing the sampled-data controller such that at each sampling time, the stability of the closed-loop system is guaranteed and an infinite horizon cost function is minimised. The main advantage of the proposed approach is to eliminate the approximations induced from discretizing the original system and cost function upper bound minimisation. Consequently, a lower bound of the cost function is obtained and the performance of the proposed model predictive controller is improved compared to the recently published papers in the same field of interest. In addition, the Euclidean norm constraint of the control input vector is derived in terms of LMIs. To illustrate the merits of the proposed approach, the proposed technique is applied to a continuous stirred tank reactor system.     

Systematic studies of structure and physiological activity of alapyridaine. A novel food-born taste enhancer

By application of taste dilution analysis (+)-(S)-1-(1-carboxyethyl)-5-hydroxy-2-(hydroxymethyl)-pyridinium inner salt was recently successfully identified as a multimodal taste enhancer in beef bouillon. While being taste-less on its own, this so-called alapyridaine was found to intensify the human perception of sweet, salty, and umami taste. To gain information on the molecular requirements of this novel class of taste enhancer, a range of structurally related pyridinium betaines were synthesized, purified, and their physiological activities sensorially evaluated. Removal or modification of the hydroxyl and the hydroxymethyl group, respectively, induced a loss in bioactivity, thus indicating the 2-(hydroxymethyl)-5-hydroxypyridinium moiety as an essential structural element for taste enhancement. Regarding the amino substituent, neither the prolongation or removal of the alkyl chain or the carboxy function in the 1-(1-carboxy-2-ethyl)-moiety, nor the incorporation of an additional carboxy function led to any active derivative, thus demonstrating that also the structure of the nitrogen substituent is rather conserved for taste enhancement. But substitution of the methyl group by a benzyl group yielded a compound showing similar taste enhancing activities as found for alapyridaine. Interestingly, additional insertion of glycine between the 1-(1-carboxy-2-phenylethyl)-moiety and the pyridinium ring resulted in a compound eliciting comparable taste enhancing effects as shown for the compound lacking the glycine spacer. In contrast to these multimodal taste enhancers, substitution of the alanine moiety in alapyridaine by an arginine moiety revealed an one-dimensional taste enhancer exclusively increasing the human sensitivity for salty taste.     

Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate K2[B3O3F4OH] inhibits emerging multidrug-resistant and β-lactamase-producing opportunistic pathogens

Abstract

Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate, K₂[B₃O₃F₄OH] (boroxine) was previously shown to be very effective in inhibition of several carcinoma cell lines, including the skin cancer. Here, we investigated its antimicrobial potential by targeting the multidrug-resistant opportunistic pathogens associated with skin and wound infections. The antimicrobial testing against eleven bacterial and four fungal species revealed good activity of boroxine against pathogenic filamentous fungi Penicillium funiculosum and Aspergillus niger (MIC₅₀ 64 and 128?µg/ml), and a moderate bioactivity against the yeast Candida albicans (MIC₅₀ 512?µg/ml). Among the tested multidrug-resistant bacteria, the best antibacterial effect, stable over a 24-h period, was observed against the methicillin-resistant Staphylococcus aureus strain (MRSA) at MIC of 1024?µg/ml. The atomic force microscopy (AFM) used to investigate the morphology of S. aureus cells revealed indentations on its cell envelope after the boroxine exposure. These results show that in addition to the antitumor effect, boroxine exerts wide spectrum antimicrobial activity, thus may help preventing the development of skin and wound-related opportunistic infections.     

Economic dispatch of virtual power plants in an event-driven service-oriented framework using standards-based communications

The accelerated evolution of power systems and the associated new trends, such as Smart Grids, has stimulated the development of various approaches in handling the problems of increased electricity demands, power market (de)regulation and power systems reliability. One of the new key concepts is the virtual power plant (VPP), which represents a controllable portfolio of distributed energy resources (DERs). Such a portfolio can be operated in various modes, each with a set of unique control requirements.An open framework providing robust solution for large scale DERs integration and control is one of the key issues in Smart Grid development. This paper proposes an approach for solving this problem by utilizing standards-based power system communications, application modeling based on event-driven information services and algorithms for optimized VPP control. The applicability of the proposed technical solution is demonstrated and analyzed via simulation of the developed economic dispatch algorithm.     

Two-stage optimization algorithm for short-term reactive power planning based on zonal approach

There are various methods for procurement of reactive power as an ancillary service in deregulated market environment. Reactive power market model based on voltage control zones and two-step optimal power flow algorithm is proposed in this paper. Zones are formed by splitting the power system or a control area of an interconnected power system into autonomous voltage sub-areas with sufficient reactive power reserves using the electrical distance method. Every zone formes a single reactive power market. First step of an optimization algorithm determines zonal reactive power prices based on generator's cost functions for reactive power production. Total cost minimization is the goal of the second optimization step where the final dispatching decision is made according to transmission losses and zonal reactive power prices respecting power system planned conditions and security constraints. Proposed algorithm is tested on IEEE 39 bus test system ensuring the system operator's minimal payment for reactive power and transmission losses, without jeopardizing power system security.     

Synthesis of Functionalized Polytriazoles via One-Pot Sequential Copper-Catalyzed Azide–Alkyne [3+2] Cycloaddition and Atom Transfer Radical Addition (ATRA)

As a continuing effort of expanding the scope of catalyst regeneration in the presence of environmentally benign reducing agents, one-pot sequential azide–alkyne [3+2] cycloaddition and atom transfer radical addition (ATRA) reactions were performed via in situ reduction of copper(II) by ascorbic acid. The formation of functionalized triazoles was achieved utilizing a ligand-free catalytic system for the cycloaddition between tripropargylamine and vinylbenzyl azide and subsequent addition of tris(2-pyridyl)methylamine (TPMA) ligand in the ATRA step. With this strategy, reactions with carbon tetrachloride and carbon tetrabromide proceeded efficiently providing the desired triazoles in nearly quantitative yields (>90 %) using 10 mol % of copper. Sequential azide–alkyne [3+2] cycloaddition and ATRA reactions were also extended to less active alkyl halides such as methyl trichloroacetate, methyl dichloroacetate and dichloroacetonitrile. The corresponding products were obtained in modest yields (50–80 %). The presented methodology enables efficient synthesis of functionalized polytriazoles, which could have a potential use as chelating agents for a variety of transition metals.     

Bacterial population in counter flow and parallel flow water chilling of poultry meat

In this study, a survey was carried out to determine the hygiene aspects of counter flow and parallel flow water chilling of poultry meat. Samples were taken in five sectors: in the sector subsequent to evisceration of the poultry, in the sector after water chilling, and in the sector after final washing. At the same time, the samples of water were taken from the pre-chilling sector and in the chilling sector. Bacterial detection of the inherence of various bacteria, their isolation, identification and determination was carried out. The results showed higher numbers of positive samples obtained from the section of water chilling in comparison to other sections, as well as a higher number of positive samples in the process of parallel flow water chilling in comparison to the results from counter flow chilling.     

Service innovation in Hong Kong organizations: Enablers and challenges to design thinking practices

East-Asian practitioners aspiring to engage in the design thinking (DT) practice—a human-centred approach to innovation developed and primarily used in Western cultures—may experience a “cultural clash” or “cultural misfit” that may inhibit the acceptance of DT logic. To tap into this still underexplored terrain, this qualitative study explores the enablers and challenges of effective DT practice in achieving service innovation in Hong Kong organizations. Based on a dozen in-depth interviews, we identified numerous sociocultural and institutional enablers and challenges, which we interpreted based on the postulates of structuration theory proposed by Giddens. Our conceptualization and empirical investigation of DT through a practice lens offers a new perspective when studying the contextual antecedents of DT. Specifically, the findings show that the choice to engage in DT practice is shaped by cultural specifics in the plurality of influences that move beyond the Western perspective and previous DT studies. From a practical point of view, our research informs policymakers and managers about the importance of being culturally sensitive and humanizing digital transformation when organizing service innovation.     

Effect of grey component replacement processing and varnishing on the light fastness of colours on cardboard prints

The visual appearance of packaging is one of its most important features. Electromagnetic irradiation causes a change in colour and often leads to colour fading (ie, to diminished visual appearance of a printed product). This research study aimed to determine the combined effect of grey component replacement image processing and varnishing on the protection of prints' appearance when exposed to accelerated ageing. For that purpose, two test charts were printed in a lithographic press and coated with water-based and ultraviolet-curable varnish before exposing them to xenon light. The prepared prints were evaluated by determining the tone values and colour difference, as well as the rub and abrasion resistance. In addition, Fourier Transform–infrared-attenuated total reflectance spectra were recorded to detect possible chemical changes caused by the (AcA). The results showed that the investigated period of (AcA) caused significant differences in the tone values of yellow, while the other primary colours proved to be more resistant. The water-based varnish provided better protection than the ultraviolet-curable varnish. The grey component replacement image processing diminished the colour difference caused by (AcA) on all the prepared print samples, and was particularly detected in tertiary colours containing the mid-range tone values of yellow (34%-68%). Both varnishes improved the rub resistance of aged prints, but only ultraviolet-curable varnish improved the abrasion resistance of both the unaged and the aged prints. In conclusion, applying varnish to prints ensured enhanced rub and abrasion resistance and diminished the colour change caused by (AcA). Finally, improved resistance to colour change was achieved by processing images with the grey component replacement method.