Corrosion resistance of a bent plate from a high-nitrogen nonmagnetic 05Kh22AG15N8M2F steel in aggressive media

The corrosion resistance of the convex and concave sides of bent plates from a high-nitrogen non-magnetic steel has been studied in aqueous solutions of sulfuric and hydrochloric acids. Weighing and hydrogen methods are used to control the corrosion rate of bent-sample sides and to find a number of effects that complement the picture of the stress corrosion of iron alloys and support the existence of the mechanochemical deformation sign effect.     

Organ distribution of bovine serum albumin administered intragastrically in the rat

Radioimmunoassay was employed to examine distribution of antigenic structures of bovine serum albumin (BSA), absorbed by the gastrointestinal tract, in the blood serum and organs of intact rats. It was shown that 3 h after administering 3H-BSA an appreciable amount of its antigenic structures could be identified in the blood serum, liver, spleen, and carcass of the animals. The total amount of antigenic determinants of BSA which got into the internal environment of the body from the intestine amounted to about 0.2% of the dose administered. The highest specific content of antigenic structures of BSA supplied via the intestinal barrier was detected in the spleen.     

Oxidative stability of the lipids in whitefish

The manometric technique was employed to study the initiated oxidation of 7 samples of whitefish lipids of varying sites, to measure the kinetic parameters depending on the fatty acid composition and concentration of tocopherol. Changes in oxidative stability of lipids of varying localization was shown, a higher stability of muscle tissue lipids was noted as compared with brain and depot lipids. The possibility of testing oxidative stability of lipids according to the kinetic parameters is discussed.     

Life history of Teretriosoma nigrescens Lewis (Coleoptera: Histeridae) and its ability to suppress populations of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)

The life history and behaviour of Teretriosoma nigrescens Lewis are typical of a histerid predator, but only 2, instead of the expected 3, larval instars were recorded. At 27°C, 70% r.h. development from oviposition to adult emergence took about 8 weeks. In 24 h at 27°C, 70% r.h., T. nigrescens adults and larvae, respectively, consumed on average up to 1.7 and 3.5 Prostephanus truncatus (Horn) larvae. After 7 weeks, 10 T. nigrescens adults prevented populations of 25, 50, 75 and 100 P. truncatus from increasing, while controls increased at least 10-fold. Grain moisture contents of between 8.5–14% had little effect on predatory efficiency.     

An assessment of the θ-projection method for the representation and extrapolation of creep data for a 1%Cr, 12%Mo, 14%V steel tested at 565°C

Constant stress creep data for a wrought 1%Cr, $\text{1}\text{2}\text{\%}\text{Mo}$, $\text{1}\text{4}\text{\%}\text{V}$ steel obtained from six tests carried out at 565°C have been fitted and extrapolated using the θ-projection method. Creep curves for high stresses were fitted well, but curves extrapolated to stress levels below those used in the θ-projection did not represent well the available data for primary-secondary creep. To enable a satisfactory extrapolation of results, it was found necessary to redefine the failure condition to be less sensitive to the shape of the latter sections of the tertiary creep curve. This was achieved by defining lifetime as the point on the curve at which the strain rate reached a fixed multiple of the creep rate at half the rupture time. The extrapolated data compare well with the results of tests carried out independently on a cast 1%Cr, $\text{1}\text{2}\text{\%}\text{Mo}$, $\text{1}\text{4}\text{\%}\text{V}$ steel. The extrapolation procedure not only predicts the ‘knee’ in the log stress-log lifetime curve but allows extrapolation of lifetimes by over a factor of thirty. In addition, acceptable predictions have been made of constant load experimental data.     

Kinetics of Folacin Destruction in Swiss Chard During Storage

The folacin activities in fresh Swiss chard leaves stored in open air at 4, 21, 35 and 40°C were determined by a microbiological assay using Lactobacillus casei. At 21°C the leaves were also stored in plastic bags and under moist conditions. Folacin was most stable when the vegetable was stored in plastic bags, followed by the moist condition, and least stable in open air at 21°C. The degradation of folacin in Swiss chard under all conditions followed firstorder kinetics. The temperature dependent folate degradation conformed to the Arrhenius equation and the activation energy was 24 kcal/mole.     

Separating inviscid flows

Summary The separating flow of an inviscid fluid is not only a limit solution of the steady separating, laminar fluid flow at high values of the Reynolds number but it is also part of its structure (Smith [1], [2]). This work aims at reexamining the separating flow of inviscid fluid past a bluff body which is fixed in an otherwise uniform stream of fluid. For the purpose of this paper we will assume that the bluff body is a circular cylinder but the theory is applicable to bodies of any shape. It is further assumed that the fluid is in steady two-dimensional motion and is inviscid and of constant density. The flow structure is assumed to consist of a separated flow region, caviting flows in which there exists a free surface on which the pressure is constant, and a wake. A twin spiral vortex model is used in order to determine the shape of the free streamline. Based on the free streamline theory the problem reduces to solving a mixed boundary value problem and a Hilbert solution for the inverse problem in the auxiliary plane is obtained. When we consider the flow in the physical plane the problem is transformed into a direct problem in which the geometry of the solid body is given in advance. We assume that the separation is smooth and thus the curvature of the free streamline at the point of free detachment be equal to that of the body surface. A numerical method for solving the two-dimensional potential flows past arbitrarily shaped curved bluff bodies is developed.When the cavitation number is zero the angle of separation is approximately 55° and the computed results predict that the position of the separation point will move backward as the cavition number increases. The relationships between the drag coefficient, and the width and length of the cavity is determined and is found to be in very good agreement with the predictions of Smith [1].     

Wind excitation of neighbouring tall buildings

There is a growing concern about the importance of interaction effects between neighbouring tall buildings subjected to wind loading. Available results indicate that both the peak dynamic response as well as the mean wind loads may increase substantially due to building interaction.An extensive wind-tunnel study of the interaction between two square prisms with a height-to-base length equal to six was undertaken at the LAC, UFRGS. Fifteen relative prism positions were studied, for wind orientations at every 15°, under smooth-uniform as well as turbulent-shear wind. Mean force and torsional moment coefficients for uniform flow were reported in previous publications. Herein, complete results for turbulent wind are given. In addition, the most important interaction effects observed under both flow conditions are discussed in detail.