LMI-based H ∞-optimal control with transients

In this article, the worst-case norm of the regulated output over all exogenous signals and initial states as a performance measure of the system is characterised in terms of linear matrix inequalities (LMIs). Optimal time-invariant state- and output-feedback controllers are synthesised as minimising this performance measure. The essential role in this synthesis plays a weighting matrix reflecting the relative importance of the uncertainty in the initial state contrary to the uncertainty in the exogenous signal. H _∞-optimal control with transients is shown to be actually a trade-off between H _∞-control, being optimal under unknown exogenous disturbances and zero initial state, and γ-control, being optimal under zero exogenous signal and unknown initial conditions, if and only if the weighting matrix satisfies a fundamental inequality. If this inequality is met, the performance measure is achieved and the explicit formulae for the worst-case disturbance and initial state are provided. If this inequality fails, the performance measure coincides with the H _∞-norm and the trade-off gets broken.     

Survey on hierarchical routing schemes in?��flat�� distributed hash tables

The first generation of DHT designs offered a completely flat structure of the key space that is randomly partitioned among participating DHT nodes. That has certain advantages, for example, even distribution of workload among nodes. On the other hand, grouping keys under a single authority or achieving latency guarantees for queries is difficult. To address these shortcomings, various kinds of hierarchy have been proposed over recent years. The last generation is hierarchical DHTs (HDHTs) where nodes are organized onto layers; each next layer consists of supernodes for the previous layer. In this survey paper, we thoroughly go over the evolution of DHTs from pure flat to pre-hierarchical. Our focus is on hierarchical schemes in DHT routing. We argue that their application is not restricted within HDHT designs. We sequentially built a set of design principles; each provides a base for hierarchical routing schemes. In the extreme case, application these principles leads to HDHT designs.     

Synthesis and characterization of {Fe2CuO} clusters as precursors for nanosized catalytic system for Biginelli reaction

The novel μ₃-oxo-bridged heterotrinuclear iron(III)-copper(II) trichloroacetates of the composition [Fe₂CuO(CCl₃COO)₆(THF)₃] (1a) and [Fe₂CuO(CCl₃COO)₆(4-DMAP)₃] (1b) have been synthesized and characterized by X-ray crystallography, IR and Mossbauer spectroscopy. These clusters were used as precursors for the synthesis of the nanosized catalytic system (～5–6 nm of γ-Fe₂O₃/CuO), which works as an efficient organic phase catalyst (～0.02 mol%) in a one-pot three component Biginelli synthesis.     

Implementation of consequent stabilization method for simulation of multibodies described in absolute coordinates

In this article, we propose methods that increase numerical efficiency of dynamic simulation of spatial multibody systems described in absolute coordinates. The successive coordinate projection method efficiently stabilizes the system constraints in the case when a non-minimal set of orientation coordinates is used to describe the orientation of bodies in space. The new procedure of generation of Newton–Euler equations is shown in detail for systems with the most popular types of joints (prismatic joint, revolute joint, etc.). The proposed algorithms were tested with models of a governor mechanism and Yamaha YZF-R1 motorcycle engine. The simulation results show that the successive coordinate projection method is stable and can be implemented for complex mechanical systems.     

Mitigation technologies and measures in the energy sector of Kazakstan

An important commitment in the UN Framework Convention on Climate Change is to conduct mitigation analysis and to communicate climate change measures and polices. In major part reducing CO₂ as well as the other greenhouse gas emissions in Kazakstan can be a side-product of measures addressed to increasing energy efficiency. Since such measures are very important for the national economy, mitigation strategies in the energy sector of Kazakstan are directly connected with the general national strategy of the energy sector development. This paper outlines the main measures and technologies in energy sector of Kazakstan which can lead to GHG emissions reduction and presents the results of current mitigation assessment.

The mitigation analysis addressed to energy production sector. A baseline and six mitigation scenarios were developed to evaluate the most attractive mitigation options, focusing on specific technologies which have been already included in sustainable energy programs. According to the baseline projection, Kazakstan's CO₂ emissions will not exceed their 1990 level until 2005. The potential for CO₂ emission reduction is estimated to be about 11% of the baseline emission level by the end of considered period (in 2020). The main mitigation options in the energy production sector in terms of mitigation potential and technical and economical feasibility include rehabilitation of thermal power plants aimed to increasing efficiency, use of nuclear energy, and further expansion in the use of hydro energy based on small hydroelectric power plants.     

Hydrogenolysis of Hydroxymatairesinol Over Carbon-Supported Palladium Catalysts

The natural lignan hydroxymatairesinol was hydrogenolysed to a potential anticarcinogenic substance matairesinol over different carbon-supported palladium catalysts. The reaction was conducted in 2-propanol at 70 °C under hydrogen flow in a stirred glass reactor. The catalysts were characterised by N₂-physisorption, CO pulse chemisorption and pH measurement of aqueous catalyst slurries. The most active catalyst (Degussa-Hüls) gave yields of matairesinol over 90% in 4 h. It was concluded that the acidity of the catalyst had a profound influence on the reaction rate.     

Synthesis and gas permeation parameters of metathesis polytricyclononenes with pendant Me3E‐groups (E = C,Si, Ge)

Metathesis polytricyclononenes were synthesized via ROMP polymerization in the presence of the 1‐st generation Grubbs catalyst and their gas‐transport properties were studied for the first time. The aim of this work was to evaluate the influence of Me₃E‐groups (E = C, Si, Ge) on gas permeation parameters of ROMP materials. New metathesis poly(3‐tert‐butyltricyclononene‐7) and poly(3‐trimethylgermyltricyclononene‐7) were obtained with high yields (up to 95%) and high‐molecular weights (M_w～3–7×10⁵ g mol^?1). The glass transition temperatures of the ROMP polytricyclononenes with Me₃E‐groups decreased when E was changed from C to Si and then to Ge. It was shown that the polytricyclononene containing Me₃Si‐groups has the highest gas permeability while the polytricyclononene containing Me₃C‐substituents has the lowest gas permeability. In addition, the gas permeation parameters were estimated for ROMP Me₃Si‐ and Me₃Ge‐substituted polytricyclonona‐3,7‐dienes. So the influence of the second double bond in the monomer units on the permeability of the polymers obtained was studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41395.