Optimization of Heat Treatment of Low-Carbon Structural Steel in “HICON/H2” Bell Furnaces

Metal Science and Heat Treatment -     

Crystallization and Conditions for Fabricating Dense Ingots from High-Nitrogen Steels

Metal Science and Heat Treatment -     

Interaction Between a Linearly Polarized Electromagnetic Plane and a Double Spherical Shell

An exact solution inside, outside, and within two arbitrary concentric spherical shells is presented for an impinging monochromatic linearly polarized electromagnetic wave. Specifically, the solution was found for a double-shell spherical acrylic plastic enclosure irradiated with 2450-MHz microwaves. The enclosure is used as an environmentally controlled exposure chamber for experimental animals during microwave irradiation. The analysis shows that an air foamed material, such as styrofoam, would be a better material than either Plexiglas or Teflon, provided it is sufficiently durable.     

Environmental Control Symposium

MAN is but a part of the universe; his capabilities make him a significant link, in the cycle of life. To ensure this life, man must live in harmony with his environment. Recently, a disharmony has been discovered which could have grave effects upon the existence of man. It appears that man in his great thrust forward is destroying his own environment. The gravity of this threat to man's own existence carries some intrinsic problems of its own: man must allow his reason rather than his emotion to take command.     

A farm level approach to define successful mitigation strategies for GHG emissions from ruminant livestock systems

Ruminant livestock systems are a significant source of greenhouse gases (GHGs). Thus far, mitigation options for GHG emissions mainly focused on a single gas, and are treated as isolated activities. The present paper proposes a framework for a farm level approach for the full accounting of GHG emissions. The methodology accounts for the relevant direct and indirect emissions of methane, nitrous oxide and carbon dioxide, including carbon sequestration. Furthermore, the potential trade-off with ammonia volatilisation and nitrate leaching are taken into account. A ruminant livestock farm is represented with a conceptual model consisting of five pools: animal, manure, soil, crop and feed. The carbon and nitrogen inputs, throughputs and outputs are described, and the direct emissions are related to the carbon and nitrogen flows. The indirect emissions included in the methodology are mainly carbon dioxide emissions from energy use and nitrous oxide emissions related to imported resources and nitrogen losses. The whole farm approach is illustrated with a case of two dairy farms with contrasting livestock density and grassland management. It is shown that the inclusion of carbon sequestration and all indirect emissions have a major impact on the GHG budget of the farm. For one farm, the effect of four mitigation options on the GHG emissions was quantified. It was concluded that a whole farm approach of full accounting contributes to a better insight in the interactions between the carbon and nitrogen flows and the resulting emissions, within and outside the farm boundaries. Consequently, the methodology can be used to develop efficient and effective mitigation strategies.     

Potentiometric titration of long chain quaternary ammonium compounds using sodium tetraphenyl borate

Current methods for determining the activity of long chain quaternary ammonium compounds (QACS) are based either on dye partition, titration, or colorimetric analysis. The two major disadvantages of these methods are the disparity of partition coefficients among differently constituted QACS and the difficulty in detecting visual end points. Some potentiometric titration methods for QACS have been reported in the literature. However, back titration techniques, as well as complicated electrode systems, are generally involved. A new potentiometric titration system is presented which uses aqueous sodium tetraphenylborate (TPB) solution as a titrant and a platinum-platinum electrode system to detect the end point. Standard potentiometric titration instruments may be used for this method. This new potentiometric method is superior in precision and accuracy to visual (colorimetric) methods. Original version presented at the 1986 Annual AOCS Meeting in Honolulu, HI.     

Orientational crystallization and orientational drawing as strengthening methods for polyethylene

This paper reports on the theoretical and experimental studies of structure formation and strengthening (stiffening) of flexible-chain polymers. Two techniques of strengthening relying on the melt extrusion, i.e., orientational crystallization (crystallization initiated by melt extension) and drawing (uniaxial stretching of a crystallized polymer) are analysed by theory. The experiments involved preparation and study of melt extruded films and film fibers of linear polyethylene formed by the two techniques mentioned above. The effect of the degree of orientation and other parameters of the formation processes on the mechanical characteristics and the factors limiting the ultimate values of these characteristics are discussed. It is shown that multistage drawing succeeds in achieving a higher tensile strength and elastic modulus (1.2 and 35 GPa, respectively) than the orientational crystallization, which gives 0.8 and 15 GPa. The strengthening by drawing is accompanied by microcrack formation. In contrast, no discontinuities are observed in orientationally crystallized samples up to their ultimate extension.     

Determination of individual long-chain fatty acyl-CoA esters in heart and skeletal muscle

A method has been developed for determination of individual long-chain fatty acyl-CoA esters from heart and skeletal muscle using high performance liquid chromatography (HPLC). The esters were extracted from freezeclamped tissue of pig and rat hearts and rat skeletal muscle for analysis on a radially compressed C₁₈ 5μ reversephase column. Nine peaks in the extract with carbon chain lengths from C₁₂ to C₂₀ that subsequently disappeared on alkaline hydrolysis were identified. The major acyl-CoA peaks were 14∶1, 18∶2, 16∶0 and 18∶1 and additionally in rat heart 18∶0. Total long-chain acyl-CoA esters obtained by summation of the individual molecular species was 11.34±1.48 nmol/g wet wt. pig heart; 14.51±2.11 nmol/g wet wt. in rat heart, and 4.35±0.71 nmol/g wet wt. in rat skeletal muscle. These values were approximately 132% of those obtained using a separate procedure that measured total CoA by HPLC after alkaline hydrolysis of the esters. The described method demonstrates the quantitation of individual acyl-CoA species in muscle tissue. Therefore, it has a number of advantages in that it permits information to be obtained on the individual molecular species under various nutritional and metabolic conditions.