On control of adaptation in parallel mesh generation

A black-box methodology of a parallel generation of adaptive anisotropic meshes is described. A control of mesh adaptation, important for robustness and flexibility, may effect parallel properties of the methodology. This is demonstrated with a 3D example.     

Direct electron transfer of cytochrome P450 2B4 at electrodes modified with nonionic detergent and colloidal clay nanoparticles

A method for construction of biosensors with membranous cytochrome P450 isoenzymes was developed based on clay/detergent/protein mixed films. Thin films of sodium montmorillonite colloid with incorporated cytochrome P450 2B4 (CYP2B4) with nonionic detergent were prepared on glassy carbon electrodes. The modified electrodes were electrochemically characterized, and bioelectrocatalytic reactions were followed. CYP2B4 can be reduced fast on clay-modified glassy carbon electrodes in the presence of the nonionic detergent Tween 80. In anaerobic solutions, reversible oxidation and reduction is obtained with a formal potential between -0.292 and -0.305 V vs Ag/AgCl 1 M KCl depending on the preparation of the biosensor. In air-saturated solution, bioelectrocatalytic reduction currents can be obtained with the CYP2B4-modified electrode on addition of typical substrates such as aminopyrine and benzphetamine. This reaction was suppressed when methyrapone, an inhibitor of P450 reactions, was present. Measurement of product formation also indicates the bioelectrocatalysis by CYP2B4.     

A lower bound on the size of ε-free NFA corresponding to a regular expression

Hromkovic? et al. showed how to transform a regular expression of size n into an ε-free nondeterministic finite automaton (which defines the same language as the expression) with O(n) states and O(nlog²(n)) transitions. They also established a lower bound on the number of transitions. We improve the lower bound to .     

Aeronautical and space vehicle control in dynamic sliding manifolds

Multiple loop multiple time scale sliding mode control technique based on dynamic sliding manifold is developed and applied to aeronautical and space vehicle control. Minimum and non-minimum phase output tracking problems for aeronautical and space vehicles are addressed in dynamic sliding manifold. Numerical examples of the flight controller design for controlling minimum and non-minimum phase manoeuvres of an F-16 jet fighter are presented. An example of an attitude controller design for the X-33 technology demonstration reusable launch vehicle using sliding mode control based on dynamic sliding manifold is also considered. Numerical simulations illustrate the effectiveness of the dynamic sliding manifold technique.     

Variants of constrained longest common subsequence

We consider a variant of the classical Longest Common Subsequence problem called Doubly-Constrained Longest Common Subsequence (DC-LCS). Given two strings s₁ and s₂ over an alphabet Σ, a set Cs of strings, and a function Co:Σ→N, the DC-LCS problem consists of finding the longest subsequence s of s₁ and s₂ such that s is a supersequence of all the strings in Cs and such that the number of occurrences in s of each symbol σ∈Σ is upper bounded by Co(σ). The DC-LCS problem provides a clear mathematical formulation of a sequence comparison problem in Computational Biology and generalizes two other constrained variants of the LCS problem that have been introduced previously in the literature: the Constrained LCS and the Repetition-Free LCS. We present two results for the DC-LCS problem. First, we illustrate a fixed-parameter algorithm where the parameter is the length of the solution which is also applicable to the more specialized problems. Second, we prove a parameterized hardness result for the Constrained LCS problem when the parameter is the number of the constraint strings (|Cs|) and the size of the alphabet Σ. This hardness result also implies the parameterized hardness of the DC-LCS problem (with the same parameters) and its NP-hardness when the size of the alphabet is constant.     

Mortarless structures based on topological interlocking

We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle. We concentrate on structures built of osteomorphic blocks – the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D structures. These structures are easy to build and can be made demountable. They are flexible, resistant to macroscopic fractures and tolerant to missing blocks. The blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking structures. The overall structural integrity of these structures depends on the force imposed by peripheral constraint. The peripheral constraint can be provided in various ways: by an external frame or features of site topography, internal pre-stressed cables/tendons, or self-weight and is a necessary auxiliary element of the structure. The constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.     

Heat Transfer Through the Interface and Flow Regimes in Liquid Bridge Subjected to Co-Axial Gas Flow

We present results of an extensive numerical study on the thermocapillary (Marangoni) convection and a heat transfer through the interface in a liquid bridge of Pr?=?68. The geometry of the physical problem is a cylindrical and non-deformable liquid bridge concentrically surrounded by an annular gas channel under conditions of zero gravity. The gas flow is co- or counter-directed with respect to the Marangoni flow. The forced gas flow along the interface provides two actions: via shear stresses and heat exchange. Usually the cooling of the interface enhances the flow while the heating slows down. This general trend may not hold when shear and thermocapillary stresses are comparable. The results show that when gas enters from the cold side the heat transfer through the interface is considerably larger than that when gas enters from the hot side.     

Ultrasonic nebulization-assisted layer-by-layer assembly for spray coating of multilayered, multicomponent, bioactive nanostructures

In this study, we describe a new technique for creating dense, stable, nanolayer coatings on solid substrates using ultrasonic nebulization. Nebulization-assisted layer-by-layer assembly (LbL) is a modification to the well-characterized LbL assembly method. The conventional method of producing electrostatically assembled multilayer films through sequential substrate dipping was compared to the nebulization method, and the resultant film characteristics were investigated. Varied coatings can be generated according to the alterations in deposition parameters, with the most influential being nebulizer distance and time. In addition to employment of polyelectrolytes (PEs), the nebulization method has been extrapolated to generate assemblies containing nanoparticles and a model drug, dexamethasone. It is shown that in comparison with conventional LbL, similar bilayers’ layering thicknesses can be achieved within a much smaller timeframe. Furthermore, PEs and more complex protein and nanoparticle assemblies can be incorporated to influence the surface topography and functionality. The potential to expeditiously assemble multicomponent films has far-reaching implications in many focus areas.