Computing via natural erosion of sandstone

Abstract

Logical gates are constructed based on a method of numerical modeling of natural erosion of sandstone. Values of logical variables are determined by the presence of sandstone. The presence of sandstone corresponds to the logical value of True, whereas the absence of material corresponds to the False value. Logical functions are computed through the formation of sandstone structures at action of natural erosion where loading conditions are specified. AND and XOR gates and a one-bit binary half-adder are implemented.     

Design of strictly positive real systems using constant outputfeedback

The authors present a linear matrix inequality (LMI) approach to the strictly positive real (SPR) synthesis problem: find an output feedback K such that the closed loop system T(s) is SPR. The authors establish that if no such constant output feedback K exists, then no dynamic output feedback with a proper transfer matrix exists to make the closed-loop system SPR. The existence of K to guarantee the SPR property of the closed-loop system is used to develop an adaptive control scheme that can stabilize any system of arbitrary unknown order and unknown parameters     

Material expenditures in deep desulfurization of steel in the ladle–furnace unit

The desulfurization of steel in a 160-t casting ladle is investigated. On that basis, a technology for reducing the sulfur content of low-carbon and low-alloy pipe steel to 0.001–0.003% is developed. The material expenditures in deep desulfurization of steel in a 160-t ladle–furnace unit are assessed.     

Analysis of the joint use of the proactive and reactive methods of the topology information dissemination in ad-hoc wireless networks

A number of routing protocols for wireless ad-hoc (self-organizing) networks selects routes according to the topology information obtained by the station. Hence, the method of these protocols used to disseminate topology information strongly affects the network performance. An unsuccessful choice of the method can lead to a large amount of traffic and the information obsolescence. These factors diminish the network performance and make it impossible to meet quality of service requirements in transmitting realtime multimedia data, which is a topical problem. The routing protocol combining the proactive and reactive methods of the topology information dissemination has been proposed. It is demonstrated that this protocol is efficient in a wide range of scenarios applied to the exchange of real-time multimedia data.     

The role of transition metal cations in dyeing of fabrics made from synthetic fibres

The use of d-metal cations in dyeing polyester fabric with dark blue K increases the dyeability to 350%. Use of VO²⁺, Fe²⁺, and Cu²⁺ cations is most effective. It is hypothesized that d-metal cations increase the number of active sites due to vacant atomic orbitals on the valence level so that the polyester fibre can sorb a larger amount of dye. The use of d-metal cations in dyeing polyester fabric increases the resistance of the color to external physicochemical effects.     

Chemical and phase composition of nanosized oxide and passive films on Ni-Cr alloys. II. XPS analysis of films produced by anodic passivation of alloys in 1 N H<Subscript>2</Subscript>SO<Subscript>4</Subscript>

XPS data of thin (1 to 2 nm) oxide films formed by the anodic passivation of Ni-2 at % Cr and Ni-6 at % Cr alloys in 1 N H₂SO₄ are discussed. Thermodynamic calculations of the solid-phase chemical reaction 3NiO + 2Cr = Cr₂O₃ + 3Ni are carried out taking into account the changes in the surface energy at the alloy-oxide film interface along with the Gibbs energy change in the alloy oxidation reaction.     

Relative-error H∞ identification fromautocorrelation data-a stochastic realization method

A variant of the balanced stochastic truncation (BST) method for approximated realization of power spectrum matrices is shown to form the basis for an identification procedure that is well-suited to the task of determining relative-error-bounded approximate plant models for use in control design from input-output cross correlation data. Central to the theory is a novel L_∞-norm bound on the relative-error between an exact realization of the data and BST approximate realization     

Zero cancelling compensators for singular control problems and their application to the inner–outer factorization problem

Many control problems fall into the category of what we call singular control problems, i.e., problems for which known solutions fail owing to the fact that the relevant transfer functions have zeros on the extended imaginary axis, ??^0e. An example of this is the inner–outer factorization (IOF) problem for such transfer functions. In this paper, we show how to design compensators which would allow for a direct solution to these problems through cancellation of the offending ??^0e zeros. This is demonstrated for the IOF problem mentioned above. Our interest lies primarily with infinite zeros but we develop formulae for finite ??^0e compensators as well. The paper also presents some discussions on the infinite zero structure of linear time-invariant systems.     

A Schur method for balanced-truncation model reduction

It is shown that a not-necessarily-balanced state-space realization of the Moore reduced model can be computed directly without balancing via projections defined in terms of arbitrary bases for the left and right eigenspaces associated with the large eigenvalues of the product PQ of the reachability and controllability Grammians. Two specific methods for computing these bases are proposed, one based on the ordered Schur decomposition of PQ and the other based on the Cholesky factors of P and Q. The algorithms perform reliably even for nonminimal models