Epoxy paint failure in B-52 fuel tanks: Part II. Influence of DIEGME concentration in the fuel on the failure process

A model has been proposed to explain the failure of the original BMS10-39 epoxy paint on upper vertical surfaces in B-52 fuel tanks. The model involves interaction of the paint with DIEGME, a fuel system ice inhibitor (FSII) in jet fuel, that is distilled from the liquid fuel. In this communication, distillation experiments used to support the model are refined to better match the mass transfer of vapor from fuel in a B-52 fuel tank at close to room temperature. The interaction of these lower temperature distillates with the paint affirms the earlier model. On the basis of these experiments it is proposed that paint failure may be controlled or eliminated by reducing the level of DIEGME in the fuel. Proposed changes in military jet fuel composition are detailed.     

Are IQ scores valid for children who are poor readers?

Remedial services for children with reading problems are often allocated according to discrepancies between reading and IQ scores. Results of some recent research suggest, however, that IQ scores of poor readers do not covary with their levels of functioning in other cognitive domains. This study evaluated whether the external validity of IQ scores (from the Wechsler Intelligence Scale for Children—Revised [WAIS—R]) was moderated by reading levels within 2 separate samples of a total of 382 referred children (aged 7–16 yrs). It was found that IQ scores had expected correlations with external measures of verbal, visual-spatial, short-term memory, and arithmetic ability, and that these relations were invariant across levels of reading skill. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Energy Dissipation at the Slug Nose and the Modeling of Solids Transport in Intermittent Flow

It is shown, by means of Lagrangian momentum and power balances across the slug nose in slug flow, that the power dissipated due to sudden expansion of the fluid in the film immediately downstream of the slug nose is greater than the power lost due to viscous action at the pipe wall but that it may not be large enough to materially aid particle transport. This has the implication that sand transport in intermittent flow may be considered as transport in a hybrid flow of hydraulic conveying and stratified flow when the length of the mixing section at the slug nose is short compared to the length of the slug body.     

A faster divide-and-conquer algorithm for constructing delaunay triangulations

An easily implemented modification to the divide-and-conquer algorithm for computing the Delaunay triangulation ofn sites in the plane is presented. The change reduces its (n logn) expected running time toO(n log logn) for a large class of distributions that includes the uniform distribution in the unit square. Experimental evidence presented demonstrates that the modified algorithm performs very well forn2¹⁶, the range of the experiments. It is conjectured that the average number of edges it creates—a good measure of its efficiency—is no more than twice optimal forn less than seven trillion. The improvement is shown to extend to the computation of the Delaunay triangulation in theL _p metric for 1<p.This research was supported by National Science Foundation Grants DCR-8352081 and DCR-8416190.     

Preferred exocyclic-amino coordination of W(CO)5 on 2-aminopyrimidine and 4-aminopyrimidine vs. heterocyclic N-1 coordination for 2-aminopyridine

2-Aminopyrimidine (2-ampym) and 4-aminopyrimidine (4-ampym) coordinate to W(CO)₅ predominantly via the exocyclic amino group (>91% in 10 min photolysis) rather than to the endocyclic N-1 position as found for 2-aminopyridine (2-ampy). Photolysis of W(CO)₆ in acetone in the presence of these ligands forms amino-bound [W(CO)₅(2-ampym)] and [W(CO)₅(4-ampym)] complexes. Secondary photolysis generates 18% (1.0 h photolysis) [W(CO)₄(2-ampym)] or [W(CO)₄(4-ampym)], chelated via the exocyclic amine and the adjacent endocyclic position (N-1 and N-3, respectively). Only ca. 10% of the more unhindered N-1-bound W(CO)₅(4-ampym) was detected compared to virtually complete coordination via the exocyclic amino group for [W(CO)₅(2-ampym)]. M 94 calculations show that the W(CO)₅ coordination to the exocyclic donor is favored by 98.8 and 95.6 kcal/mol over the adjacent endocyclic position in the 2-ampym and 4-ampym complexes, respectively. Calculated W–N bond lengths by the M 94 methods gave exo-amine W–N bond distances of 2.24 and 2.26 Å and theoretical adjacent endocyclic W–N bond distances of 2.37 and 2.35 Å (isomers not observed from photolysis) for the 2-ampym and 4-ampym complexes, respectively. A W–(N-1) bond of 2.28 Å for this isomer of [W(CO)₅(4-ampym)] was calculated. All W–N bonds are near the 2.18–2.33 Å range (mean of 2.27±0.06) for [W(CO)₅L] (L=pyridine, piperidine, glycine, 1-(2-py)-1,2,4-triazole, [W(CO)₅CN]⁻, 5-MeU⁻).     

Extraction methods for drying oils

Summary The general trend in the industry is toward solvent-extraction recovery and to larger plants. Technological change in recent years has been largely in improved equipment and process improvements to decrease operating costs and improve product quality. It is the author’s opinion that the trend mentioned above and this type of technological change will continue in at least the near future. It is expected that any radical change in processing will come about only by a radical change in raw material or products desired rather than by the development of really new equipment or process methods. One interesting development in recent years is the increasing relative importance of the residue solids compared to the oil in the case of some of the materials. Plants have been built primarily as a source of protein rather than oil in certain cases. It also accounts for the incidence of some small plants in the raw material “fringe” areas contrary to the general trend.     

Non-hierarchical control of a flexible manufacturing cell

As hierarchically controlled computer-integrated manufacturing systems growthey tend to become complex and their designability, maintainability, expandability and fault tolerance deteriorate. As an alternative, herterarchical control architectures offer prospects of reduced compexity, reduced software development costs, high modularity, high flexibility, and improved fault tolerance. By locating decision making where information originates, global information is reduced to a minimum, scheduling becomes dynamic, machines and parts become “intelligent” entities that cooperatively interact, and the overall system is decomposed into functionally simplified, modular parts.Three flexible machining cell control systems have been constructed at the University of Wisconsin-Madison and are described in this paper: a centralized controller, a hierarchical controller with dynamic scheduling, and a fully distributed heterarchical controller with “intelligent parts”. Comparative results are reported showing that the heterarchical approach possesses a number of advantages including increased fault-tolerance, inherent adaptability and reconfigurability, decreased complexity, and reduced software development cost.     

Assessment of Wilson and NRTL equations in vapor‐liquid equilibria prediction

Abstract

This work considers the application of Wilson and NRTL equations in the multicomponent VLE prediction. We emphasize the critical comparison of partially miscible solution treatment by these two equations. Results revealed NRTL equation performed slightly better than the Wilson equation in data credibility so far as the systems examined are concerned. Estimation of optimum NRTL parameters requires further exploration. Optimization methods of pattern search, gradient search and golden section were employed in this study. All of the computations were performed on an IBM 1130 digital computer.