Microstructure and corrosion behaviour of plasma‐nitrocarburized sintered steel

Powder characteristics and manufacturing processes determine the microstructure, and therefore, the physical, chemical, and mechanical properties of sintered steels. In particular, porosity and corrosion resistance are intimately related, since the contact area between substrate and electrolyte significantly affects the corrosion resistance of sintered steels. This study addresses the effect of powder characteristics and pressing parameters on the microstructure and corrosion resistance of low‐carbon sintered and sintered/plasma‐nitrocarburized steel. The results indicated that the corrosion resistance increased with increasing density and decreasing specific surface area. Additionally, plasma‐nitrocarburizing was highly effective in coating open pores of the material.     

Transitional cell neoplasm of the bladder in childhood: presentation of a clinical case

The authors report their experience with the use of loco-regional anaesthesia for the surgical treatment of inguinal and femoral hernias. Their series includes 1730 operations, 235 of which for hernia relapses, performed exclusively in the outpatient department. In the authors opinion, with loco-regional anaesthesia it is possible to treat any type of inguinal-femoral hernia, reducing the risks related to total anaesthesia and the complications arising from bedrid. Excellent results were achieved especially in the elderly and high risk patients like cardiopathic or those affected by respiratory and hepatorenal insufficiency with a complete absence of mortality and morbidity.     

OPTIMAL DESIGN AND PERFORMANCE OF SPIRAL WOUND MODULES II: ANALYTICAL METHOD

Simple explicit equations are derived for the specific permeation rate of spiral wound modules with constant and tapered permeate channels. These have been derived by taking into account the pressure drop in the brine and permeate compartments and an effective pressure difference between the two. From them, other explicit relationships are also worked out for the evaluation of optimum thickness of the brine and permeate channels. Few error percentages arc obtained when their results are compared with those of numerical methods. Their quick and simple use make them attractive to those involved in module and plant design.     

Intersection type assignment systems with higher-order algebraic rewriting

General computational models obtained by integrating different specific models have recently become a stimulating and promising research subject. In particular, extensions of various λ-calculi with algebraic rewriting, either typed or untyped, have been deeply investigated. In the present paper this subject is addressed from the point of view of type assignment. A powerful type assignment system, the one based on intersection types, is extended with first- and higher-order algebraic rewriting, and relevant properties, like strong normalization and completeness, are proved.     

Rheology of spray-dried egg yolk-stabilized emulsions

This paper deals with the influences that concentrations of oil fraction (65–77.5% w/w) and egg yolk (1–5% w/w), as well as temperature (5–35 °C), exerted on the droplet size distribution and rheological functions of concentrated oil-in-water food emulsions that were stabilized by a spray-dried egg yolk product. This work must be considered as a preliminary study concerning the use of low-in-cholesterol egg yolk as emulsifier. In order to achieve this aim, steady-state flow and dynamic viscoelasticity tests were done with emulsions processed with a rotor-stator turbine. The same processing conditions were always maintained. All of the emulsions prepared showed a high stability. An increase in oil fraction yielded higher values for the rheological functions, and larger droplet diameters. The influence of processed egg yolk concentration was more complex. Thus, an increase in egg yolk content yielded lower values for the rheological functions, but, after a particular concentration, a further increase in emulsifier content yielded higher values for the rheological functions. The experimental results have been discussed taking into account the close relationship between rheology and emulsion structural parameters.     

The electrical conductivities of steel and other candidatematerials for shrouds in a beam-waveguide antenna system

This article presents the results of electrical conductivity measurements made at 8.420 GHz on samples of the structural steel material used to fabricate shrouds on a Deep Space Network (DSN) 34-m-diameter beam-waveguide (BWG) antenna. Test results show that the structural steel samples at this microwave frequency had effective conductivities that were about 50 times worse than published dc values and also 230 times worse than the measured conductivities of aluminum test samples. Conductivity data are also presented for other candidate materials that could be used to fabricate BWG shrouds. Of interest are the improvements or degradations that were observed after some of the metal test samples were surface treated, plated, or painted     

Supporting complex inquiries

Most of the detectives' and magistrates' task can be regarded as “knowledge processing.” They have, typically, to acquire knowledge chunks (the clues), make hypotheses, find the contradictions inside and across the various depositions, link the consistent hypotheses in a causally connected lattice (the proof), judge the credibility of the testimonies and the reliability of the various witnesses. Sometimes the complexity of the case could justify the assistance of an intelligent decision support software. We present the general structure of an Inquiry Support System whose aim is to help a detective or a judge in: (1) generating hypotheses (automatically in some stereotypical cases), (2) eliciting a maximally consistent set of beliefs as the most believable piece of knowledge to reason with. This is done by: (1) finding the incoherences inside and across the various depositions, (2) generating the alternate maximally consistent sets of beliefs, (3) estimating the credibilities of the various evidences, and (4) estimating the reliabilities of the various informants. the solution of the case is intended to be searched among the various possible plots compatible with the maximally consistent set of beliefs retained by the system as the most believable one. © 1995 John Wiley & Sons, Inc.     

Dynamic maintenance of planar digraphs,with applications

Algorithmica - We show that a planarst-graphG admits two total orders on the setV∪E ∪F, whereV, E, andF are respectively the set of vertices, edges, and faces ofG, with ¦V¦...