Efficient VLSI array processing structures for adaptive quadratic digital filters

In this paper we introduce a class of efficient architectures for adaptive quadratic digital filters. These architectures are based on the LMS algorithm and use the rank compressed lower-upper (LU) triangular deomposition method. These architectures exhibit high parallelism as well as great modularity and regularity. We also consider affiliated VLSI array processing structures and compare these in terms of hardware cost and data throughput delay. For comparison purposes, the distributed arithmetic structures of adaptive quadratic filters are also included in the paper. Finally, the convergence performance of the adaptive quadratic filters is tested via benchmark simulation examples.This work was supported by National Science Foundation Grant ECS-8601307.     

Learning automata routeing in connection-oriented networks

Learning automata are used at the source nodes of a connection-oriented network to dynamically route newly arriving virtual calls to their destination. First, two new learning automata are introduced. Then, these two learning automata, as well as the well-known L Learning automaton and the deterministic shortest-path algorithms are used in a simulation program to route virtual calls. The more frequent the updating and the more recent network state information used, the better the performance. In the sequence, the virtual link length is developed as a function of both the number of packets and the number of virtual calls at the network link. This virtual link length is used in the learning automata routeing algorithm and is shown via simulation to be superior to the minimum packet delay or shortest-queue-type link length, usually used in real networks. Thus, in connection-oriented networks, not only the packet but also the virtual call traffic characteristics should be used in the routeing decisions. Furthermore, when the network state information is out-of-date, or when there are few virtual calls and each one carries a large number of packets, then the virtual link length should be based more on the number of virtual calls than on the number of packets at this link. On the other hand, when the network state information is current and there are many virtual calls and each one carries a small number of packets, then the virtual link length should be based more on the number of packets than on the number of virtual calls at this link.     

Simulation of piston ring tribology with surface texturing for internal combustion engines

Design of piston rings is a very crucial subject in the field of internal combustion engines. In the present paper, a numerical model is created using the Navier–Stokes equations. Fluid–structure interaction analysis is performed in order to calculate the structural integrity of the ring for several engine operational conditions and texturing patterns. This paper illustrates the hydrodynamic friction force under various surface artificial texturing in terms of spherical and rectangular microdimples. Piston ring stress analysis is also investigated due to gas leakage. Results show a substantial reduction of the friction using rectangular texturing and less reduction using spherical texturing. The rectangular microdimple parameters were considered to obtain a better friction reduction with the following configurations: H_d = 4 µm, ρ_τ = 0.61, λ = 20 and s = 0.004. Each rectangular texture cell is defined by the dimple depth, H_d; the texture density, ρ_τ; the dimple aspect ratio, λ; and the relative dimple depth, s. Copyright © 2014 John Wiley & Sons, Ltd.     

Removal of As(V) from wastewaters by chemically modified fungal biomass

Biosorption has been demonstrated to be a useful alternative to conventional treatment systems for the removal of toxic metals from dilute aqueous solution. The objective of this paper was to examine the main aspects of a possible strategy for the removal of arsenates, employing P. chrysogenum biomass. The pretreatment of biomass with common surfactants (as hexadecyl-trimethylammonium bromide and dodecylamine) and a cationic polyelectrolyte was found to improve the biosorption efficiency. The initial biomass showed a relative low affinity for metallic anions, whereas with the application of modified samples a significant uptake of arsenic was observed. Sorption data were well described by typical Langmuir and Freundlich adsorption isotherms. Promising results were obtained in laboratory experiments and effective As(V) removals were observed.     

Environmental effects on fatigue behavior of adhesively-bonded pultruded structural joints

The fatigue response of adhesively-bonded pultruded GFRP double-lap joints has been investigated under different environmental conditions. Tests were performed at ?35 °C, 23 °C and 40 °C. A fourth set of fatigue data was collected from tests on preconditioned specimens in warm (40 °C) water. The tests were performed at 40 °C and at 90% relative humidity. Specimens were instrumented with strain and crack gages to record fatigue data. In addition to the S–N curves, stiffness fluctuations and crack initiation and propagation during fatigue were monitored. The dominant failure mode was a fiber-tear failure that occurred in the mat layers of the GFRP laminates. In the presence of high humidity, the failure shifted to the adhesive/composite interface. Although the testing temperature was lower than the glass transition temperature of the adhesive, its influence on the fatigue life and fracture behavior of the examined joints was apparent and was aggravated by the presence of humidity.