An improved apparatus for oxygen bomb testing

An improved oxygen bomb apparatus has been developed. The increased precision and readability of the continuous pressure recording allows a new method of end-point measurement. It was possible to use smaller test samples than any previously reported. Sample size and oxygen pressure were shown to be relatively unimportant variables. Temperature is the most useful variable for controlling test time. This is preferable over sample dispersion or addition of catalysts in terms of simplifying the procedure. Peroxide formation at the oxygen bomb test end point is three to four times the value at the end point of the Active Oxygen Method. Presented at the AOCS meeting, New Orleans, April 1976. Part I of a series on Evaluation of Antioxidant Performance.     

Fabrication of SiC-Whisker-Reinforced MoSi2 Composites by Tape Casting

In this paper, we describe a procedure for the processing of SiC-whisker-reinforced MoSi₂ composites via tape casting. Based on the characteristics of SiC whiskers and MoSi₂ powder in aqueous and nonaqueous solvents, a slip formulation (solvent, dispersant, binder, etc.) has been developed. The formulation developed allows for a uniform distribution of SiC whiskers in the matrix, easy separation of the tapes from the polymeric carrier, convenient control of both tape thickness and orientation of SiC whiskers, and a low binder burnout temperature. The latter is important for the prevention of the oxidation of MoSi₂ powder during the binder burnout in an oxidizing atmosphere.     

Free radicals in coal and coal conversions. 8. Experimental determination of conversion in hydroliquefaction

The results of conversion determinations on the products from Powhatan No.5 coal liquefied in an autoclave and in a high-pressure, high-temperature e.s.r. cavity are reported. Oil, asphaltene and preasphaltene yields, and overall conversion have been determined for Powhatan No.5 coal samples liquefied in tetralin, SRC-11 heavy distillate, and naphthalene at temperatures from 400 to 480 ° C in both reactor systems. The concept of reaction severity is introduced and used to formalize the relation between the effect of temperature and reaction time on oil yield and conversion. Oil is the predominant product in liquefaction in tetralin or naphthalene, asphaltene is the major product of liquefaction in SRC-II heavy distillate. Retrogressive reaction (THF-insoluble product formation) becomes severe when SRC-II heavy distillate is the liquefaction solvent and residence time of >10 min are used at temperatures >450 °C. Preasphaltenes appear to be the only intermediate species in Powhatan No.5 liquefaction.     

Reaction of hexamethylphosphorous triamide with cotton cellulose

The reactivity of hexamethylphosphorus triamide, (P[N? (CH₃)₂]₃) (HPT), with cotton cellulose was examined under various conditions. HPT was found to react readily with the cellulose to produce a cellulose phosphite and/or phosphate ester having approximately one acidic hydrogen atom per phosphorus atom. The reaction of HPT with cotton cellulose was efficiently catalyzed by dimethylamine hydrochloride (1%). The phosphorus content imparted by the catalyzed reaction on cotton fabrics was approximately twice that imparted by the uncatalyzed reaction. Flame resistance of the treated fabrics ranged from fair to excellent. The treated fabrics also exhibited ion exchange properties and some crosslinking.     

Aeroelastic tailoring and scaling using Bacterial Foraging Optimisation

Bacterial Foraging Optimisation (BFO) is investigated in an attempt to evaluate its use in solving complex optimisation problems for aeronautical structures. A hybrid variant of BFOA, which incorporates meta-modelling techniques, is also proposed and employed. The efficiency and effectiveness of the methods are tested for tailoring a rectangular composite wing, aiming to maximise the flutter speed and for scaling a joined-wing aircraft, targeting to match aeroelastic responses between the physical prototype and wind tunnel model. The obtained results are compared with those found using a range of other biologically inspired optimisation methods (GA, PSO, ACO), proving that the social foraging behavior of motile bacteria is an effective tool for aeroelastic optimisation.     

Responses to prey chemicals by a lacertid lizard,Podarcis muralis: Prey chemical discrimination and poststrike elevation in tongue-flick rate

The ability to discriminate prey chemicals from control substances and the presence of a poststrike elevation in tongue-flicking (PETF) rate are experimentally demonstrated in the lacertid lizard,Podarcis muralis, The tongue-flick attack score, a composite index of response strength, was significantly higher in response to integumental chemicals from cricket than to cologne or distilled water. The cricket chemicals additionally elicited a significantly greater rate of tongue-flicking and higher proportion of attacks by the lizards than did control stimuli. PETF combined with apparent searching movements strongly suggest the presence of strike-induced chemosensory searching (SICS). Experimental evidence indicates that both PETF and SICS occur in insectivorous representatives of three families of actively foraging autarchoglossan lizards, suggesting their widespread occurrence in such lizards. The adaptive roles of chemosensory behavior in the foraging behavior of P.Muralis are discussed. It is proposed that these lizards may form chemical search images and that PETF and SICS may have been present in the lacertilian ancestors of snakes.     

Fischer-tropsch synthesis on a precipitated iron catalyst: Influence of silica support on product selectivities

The influence of silica support on the α-olefins, internal olefins and branched hydrocarbon selectivities of the gasoline range products of a precipitated iron catalyst in the Fischer-Tropsch synthesis was investigated. Three catalysts with varying silica content and constant promoter content were studied. It was found that there is a linear relationship between the silica content of the catalysts and the internal olefin and branched hydrocarbon product selectivities. The selectivities of the aromatic and alcohol products remain relatively constant, indicating that the production of these two groups of compounds is not affected by the presence of silica support in the catalysts.     

—Review Paper—Current State-Of-The-Art Measurements Of Ozone In The Gas Phase And In Solution

This paper is a critical review and summary of the analytical procedures currently used by operating water utilities to control ozone treatment processes, considering disinfection as well as the many oxidative applications of ozone in water treatment applications. The role of common interferences in the various methods is described.

In operating U S., Canadian, European, and Japanese water treatment plants currently employing ozone as a primary disinfectant, ozone nearly always is followed by the addition of small quantities of chlorine, chlorine dioxide, or chloramine to provide the residual in the distribution system and to act as a secondary disinfectant. Clearly, the analytical procedures used must distinguish between the various species. This review critically presents these various factors and their implication with respect to “true values” of ozone determined under widely varying conditions.     

Morphology and properties of poly(vinyl chloride)–polyurethane blends

The objective of this research was to study the morphology and properties of PVC–polyurethane blends. Studies on blends of a segmented polyether polyurethane with PVC were carried out utilizing differential scanning calorimetry, Rheovibron, stress–strain, infrared peak position studies, and infrared dichroism experiments. This thermodynamically incompatible system was made kinetically compatible by precipitation from tetrahydrofuran (THF) solutions. THF–dioxane solution casting and melt processing produced an incompatible system. The compatible polyurethane–PVC system contains a well-mixed PVC–polyether matrix phase as evidenced by T_g shifts, orientation characteristics, and infrared peak position changes. The aromatic urethane segments which exhibit microphase separation in the pure polyurethane are not solubilized by blending with PVC by any of sample preparation methods used in this study.     

Aqueous gel permeation chromatography: The effect of solvent ionic strength

Porous glass packing materials have been used for gel permeation chromatography using an aqueous phosphate buffer. Elution volumes were determined for polystyrene sulfonates, dextrans, and small neutral and charged molecules at three different ionic strengths, viz., 0.01M, 0.1M, and 1.0M phosphate, pH 7.0. The pore diameters of the glasses studied were 75, 240, 700, and 2000 Å. Elution volumes of nonionic species were unaffected by changing the solvent ionic strength. Elution volumes of charged species were markedly affected by the ionic strength of the solvent. This was attributed to a combination of decreased polymer dimensions and decreased ionic exclusion with increasing buffer concentration. The use of low ionic strength solvents may be exploited to tailor the separating range for polyelectrolytes with porous glass packings. This is particularly useful in the low molecular weight range where the lowest pore size available is 75 Å.