The local spatial autocorrelation and the kernel method for identifying black zones: A comparative approach

This article aims to determine the location and the length of road sections characterized by a concentration of accidents (black zones). Two methods are compared: one based on a local decomposition of a global autocorrelation index, the other on kernel estimation. After explanation, both methods are applied and compared in terms of operational results, respective advantages and shortcomings, as well as underlying conceptual elements. The operationality of both methods is illustrated by an application to one Belgian road.     

A pseudo-neural system for hypothesis selection

The article describes a system for hypothesis elicitation and ranking formed by a net of computational elements obtained by modifying the classical neural model of Caianiello. This neural structure was chosen on the basis both of knowledge representation and of parallel processing considerations. the two fundamental components of the system are an elaboration layer and, in case the available evidences are insufficient to trigger explanatory hypotheses, a query layer that enables the system to gather additional information. Algorithms that help setting the crucial variable parameters of the net are described in the Appendix. © 1992 John Wiley & Sons, Inc.     

Dynamic Contextual Adaptation

When developing systems based on COTS, components need to be adapted in most of the occasions to work under certain conditions which were not initially predicted by their developers. Thus, it is very important to provide systems with the skill to dynamically alter their behaviour while running, depending on the changing conditions of the environment. In this work we describe a context-dependent, dynamic mapping between the interfaces of the components being adapted, overcoming some of the limitations of the static mappings presented in previous works. This is achieved by means of contextual environments, which define flexible adaptation policies. We also present a case study, illustrating the proposal, and discuss the improvements these mappings represent in comparison with previous works, as well as some open issues.     

Evaluation of Diluted and Undiluted Trickle-Bed Hydrotreating Reactor with Different Catalyst Volume

In this work, a comparative study on the combined effects of hydrodynamics and kinetics on the hydrodesulfurization (HDS) of a straight-run gas oil (SRGO) using a trickle-bed reactor with and without diluent (SiC) and different catalyst volume (0.1, 0.07, and 0.050 × 10^-3 m³, respectively) was carried out. The tests were conducted in a pilot plant under conditions close to those used in industrial-scale units (5492 kPa, 445.4 m³(STP)/m³ H₂/oil ratio, 623-643K, 0.9 and 2.5 h^-1 LHSV values). The catalyst used was a commercial CoMoP/Al₂O₃ formulation shaped as tri-lobed extrudates (1/20 in, nominal size) or as crushed particles (d_p = 1.2 × 10^-3 m). Contrarily to that usually claimed, the undiluted systems showed better performance than those comprising small diluent (SiC) particles (d_p ~ 5 × 10^-5 m). Calculations to evaluate hydrodynamic variables (plug-flow behavior, wall effects, wetting, and back-mixing) were carried out in order to explain the observed facts. The possible influences of the size of the diluent particles used are discussed.     

Improving the moisture resistance of adobe structures

Mud plasters or soil stuccos are commonly used to protect adobe walls from water erosion. Due to drying shrinkage cracks and high permeability, the commonly used soil stuccos are not durable. Stucco stabilizers such as Portland cement, lime and asphalt are expensive. An experimental study undertaken to evaluate some of the locally available, inexpensive, stucco stabilizers is reported here. Crack-resistant stucco compositions made with a cactus solution are described and techniques to make the stucco surface impervious to water are discussed. The results of durability tests involving simulated rainfall on stucco panels, and stucco applied to adobe walls, are presented. Recommendations for field practice are also given.     

Electron effective mass in InuGa1−uPvAs1−v for 0 ≤ v ≤ 1

The electron effective mass in In_uGa_1−uP_vAs_1−v has been measured on seven samples lattice-matched to InP and evenly spaced in values of v between 0 and 1, using the temperature dependence of the amplitude of the Shubnikov-de Haas oscillations at high magnetic fields. Values of the carrier concentrations, Hall mobilities and Dingle temperatures measured on these samples are also reported. Work sponsored in part by the National Science Foundation, Grant No. ENG 76-09586, and in part by International Telephone and Telegraph Electro-Optical Products Division. Work done in part at the M.I.T. Francis Bitter National Magnet Laboratory. Funded in part by the National Science Foundation under Grant No. DMR-76-80895.     

Carotene cooxidation activity of tomato lipoxygenase-2

The tomato isoenzyme lipoxygenase-2 presented a carotene cooxidation activity; it showed more activity with linoleic acid as substrate than with linolenic acid. The lipoxygenase was inhibited by reagents of the disulphide groups (dithiothreitol and 2-mercaptoethanol) and —SH groups ((4-hydroxymercuri)benzoic acid and iodoacetamide) and some antioxidants.