A new batch solvent-extraction pilot plant

Summary and Conclusions A new improved batch solvent extraction plant and its versatility of design have been described. Data have been given on the cost and initial test operations. The performance of the plant has been tested, and its value as a research tool has been demonstrated by the production of free gossypol and meals low in gossypol for use in research. Simplicity of operation is borne out by the fact that only one operator is needed. A limited number of detail drawings of the plant are available on written request from the Southern Regional Research Laboratory. Presented at the fall meeting, American Oil Chemists’ Society, Nov. 2–4, 1953, in Chicago, Ill. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

The effect of processing conditions upon the nutritional quality of vegetable oils

On the basis of the chemical, physical, and biological criteria used, all of which have been shown to be sensitive indicators of heat damage to oils, it must be concluded that the overall nutritional quality of an oil is not adversely affected by alkali refining, adsorptive decolorizing, or deodorization; that higher temperatures of deodorization (238C) produce oils nutritionally equivalent to those deodorized at lower temperatures (160C); and that the normal processes used in manufacturing edible oils improve the resistance of these oils to heat damage. Presented at the 6th Congress of the International Society for Fat Research, London, 1962.     

Kinetic modelling of the catalytic conversion of synthesis gas

A kinetic study for the one-step conversion of synthesis gas to gasoline on a ZnO–Cr₂O₃–ZSM-5 catalyst is described. On this catalyst, three reactions are involved in the overall transformation of synthesis gas: the methanol synthesis, the conversion of methanol to hydrocarbons and the water–gas shift reaction. Under the operating conditions selected for the study, it was found that the water–gas shift was at equilibrium and the methanol was completely converted to hydrocarbons. Consequently, it was postulated that the kinetics of the limiting reaction step, the methanol synthesis on the ZnO–Cr₂O₃ component, was the one that controls the overall reaction rate. Three kinetic model equations describing the rate of synthesis gas conversion on the bifunctional catalyst, were considered to fit the data of the experimental runs performed in a Berty well-mixed reactor. Those equations were derived under very special conditions where the methanol decomposition term could be neglected. It was also observed that in the kinetic equations a term involving the fugacity of CO₂ was required to predict the rate properly. The catalyst deactivation was also taken into account in the analysis.     

EMI shielding of intinsically conductive polymers

Results of this study, in which shielding efficiencies are measured for a number of blends containing various conductive fillers including intrinsically conductive polymers, are reported. It is shown that a very high level of shielding performance can be achieved by use of intrinsically conductive polymers in thermoplastic blends and that the most reliable measure of this performance is obtained from far-field shielding measurements. However, near-field measurements provide a useful method for comparing the relative shielding effectiveness of different samples. A PVC blend containing nearly uniformly dispersed intrinsically conductive polymer proved to be the best performing sample.     

Activating pulp toward acetylation by chemical or mechanical means

Activation of pulps during acetylation, by prior mechanical or chemical treatment, has been investigated. The effect of degree of beating on the acetylation rate of wood and bagasse pulps has been studied. It is found that the acetylation rate of pulps increases when the degree of beating of pulps is increased to a definite degree, after which it slows down. The maximum reactivity of bagasse pulp is obtained at 50°SR, while that of wood pulp is observed at 30°SR. The effect of grafting of acrylonitrile onto bagasse and wood pulps on their reactivity during acetylation has been also studied. The results indicate that grafting of acrylonitrile onto pulps has a favorable effect on their acetylation rate. This is dependent on the degree of grafting as well as the origin of pulp fibers. The most suitable method of activation during acetylation reaction is dependent on the origin of the pulp. The reactivity of bagasse pulp during acetylation is influenced more by beating of pulp, prior to the reaction, than by the grafting of acrylonitrile onto pulp. On the other hand, the acetylation reaction of wood pulp is activated by grafting rather than by beating. Also the effect of the activation process, mechanical or chemical, on the strength properties of the paper sheets produced from acetylated pulps has been investigated. Chemical activation of wood pulp prior to acetylation resulted in pulp with slightly higher strength properties than that activated by mechanical means. But, in the case of bagasse pulp, mechanical activation resulted in a pulp with strength superior to that produced by chemical activation.     

Tensile behavior of glass fiber-reinforced acetal polymer

The tensile stress-strain behavior of glass fiber-reinforced polyacetal resin was investigated for various fiber concentrations, fiber length distributions, and finishing agents. The polyacetal fiber blends change considerably in strength and elongation at break when treated with ammonium chloride, but otherwise similar specimens still follow a common stress-strain curve to a point shortly before failure. As the mean fiber length decreases, the modulus and tensile strength fall, but the elongation at break remains almost unchanged. The observed tensile behavior is discussed in terms of a simplified model, which assigns the fibers to two categories: a fraction α parallel to the applied load, and the remainder distributed in a plane perpendicular to the load axis. By fitting this model to the stress-strain curves, two other constants of each system are derived: a length-dependent efficiency factor β for parallel fibers, whose magnitude agrees with the predictions of Rosen and his co-workers, and a factor γ which expresses the constraint of the matrix resin by the “transverse” fibers. The behavior of γ is consistent with Tsai's theory of the transverse modulus of laminates, if a reasonable amount of fiber–fiber contact is assumed. In terms of this model, possible interpretations of the behavior under repeated loading and the mechanism of tensile failure are presented.     

Mechanical Behavior of Several Hybrid Ceramic-Matrix-Composite Laminates

Several different hybrid laminated composites comprised of alternating layers of dense ceramic sheets (either SiC or Si₃N₄) and fiber-reinforced ceramic-matrix-composite (CMC) layers (Nicalon fibers with either glass or glass-ceramic matrices) have been fabricated and characterized. The effects of the reinforcement architecture (unidirectional vs cross-ply) and the relative volume fractions of the phases on the tensile and flexural properties have been examined. Comparisons have been made with the properties of the constituent layers. Rudimentary models have been developed to describe the onset of cracking and for the minimum volume fraction of CMC required to develop multiple cracks and thus obtain a high failure strain.     

Effect of γ-irradiation on strength of concrete for nuclear-safety structures

Concrete applied for construction of nuclear power plant (NPP) Temelín (Czech Republic) has been exposed to γ-irradiation up to dose 6×10⁵ Gy. Depending on the level of irradiation, changes in strength, porous structure and phase composition of the concrete have been studied. It is found that irradiation lowers both the strength of concrete (about 10%) and volume (resp. surface) of porous space. On the other hand, γ-irradiation increases the ratio of calcite, CaCO₃, in the concrete. Observed effects are discussed with respect to safety of NPPs.     

Lactobacillic and methyl-branched olefinic acids inByrsocarpus coccineus seed oil

A detailed investigation of the seed oil ofByrsocarpus coccineus Schum. and Thonn. has disclosedcis-11,12-methyleneoctadecanoic (lactobacillic) (13%) and two branched octadecenoic acids (0.1%). Other fatty acids in the oil are those normally associated with seed lipids except for an unusually high proportion (12%) ofcis-11-octadecenoic acid. Lactobacillic acid has long been known as a constituent of certain bacterial lipids, but this is the first report of its presence in a seed oil. The branched olefinic acids have not heretofore been found to occur in plants. Mention of firm names or trade products does not imply endorsement or recommendation by the Department of Agriculture over other firms or similar products not mentioned.     

On the nature of the active state of silver during catalytic oxidation of methanol

Under the applied high reaction temperatures (900 K) the Ag surface is restructured and a tightly held oxygen species is formed on the surface (O) apart from O atoms dissolved in the bulk (O). Methanol oxidation to formaldehyde proceeds through this O species as demonstrated by application of a variety of spectroscopic techniques.