Elimination of the halphen response of cottonseed oils in conjunction with deodorization

Two simple but effective pilot-plant processes were developed to produce Halphen-negative cottonseed oil. Both involve treatment of the oil with cottonseed fatty acids in a conventional batch type of deodorizer in conjunction with deodorization. In one process, in which the acids were added to the oil, the cyclopropenoids were inactivated in as short a time as 5 min after the oil reached the maximum temperature of 450–455 F. In the other, in which the acids were generated in situ, the oil did not become Halphennegative until about an hour and 45 min after it reached maximum temperature. The excess acids produced by both methods were readily removed during conventional deodorization. In contrast, deodorization alone reduced the cyclopropenoid content of the oil to a low level (0.02%) but did not render it Halphen-negative even after 3 hr at maximum temperature. These new processes are directly applicable for use by refineries that have the batch type of deodorizers. For refineries that operate continuous or semicontinuous deodorizers, it should be relatively simple to design preheating vessels or heat exchangers to inactivate partially or completely the cyclopropenoids before deodorization. Presented at the AOCS Meeting, New Orleans, May 1967. So. Utiliz. Res. Dev. Div., ARS, USDA.     

The difficultly extractable lipides of cottonseed meats,their composition and effect on the refining characteristics of the crude oils

Summary and Conclusions Crude lipides fractions were produced from raw, tempered, and cooked meats from two lots of cottonseed by a series of successive stepwise extractions, designed to obtain fractional portions of the total lipides in the order of the difficulty of their extraction. The proximate composition of the crude lipides fractions was determined. It was found that the composition of successive lipides fractions varied with the degree of exhaustiveness of extraction. The fractions obtained by more exhaustive extraction contained greater amounts of undesirable non-neutral oil material and lesser amounts of desirable neutral oil. It was also established that the method used in preparing meats for extraction was of paramount importance in its effect on the composition of the crude lipides obtained. The crude lipides fractions from raw and tempered meats contained large amounts of impurities while the crude lipides fractions similarly obtained from cooked meats were relatively low in impurities. Crude oils equivalent to varying degrees of total lipides extraction were reconstituted from the crude lipides fractions and evaluated for refining characteristics. The impurities content of the reconstituted oils varied as the degree of total lipides extraction and increases in the impurities content of the oils were generally reflected in disproportionate increases in refining losses and/or refined oil color. The oils obtained from the cooked meats at all degrees of extraction were outstandingly low in refining losses as compared to the oils from the raw and the tempered meats. Presented in two parts at the spring meeting, American Oil Chemists’ Society, New Orleans. La., Apr. 18–20, 1955, and at the fall meeting, Philadelphia, Pa., Oct. 10–12, 1995. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Thermally initiated oxidation and ignition of flexible polyurethane foams

Oxidation and ignition of flexible polyurethane foams have been investigated by observing the effects of internal and external heating. External temperatures of some 190°C are required to induce combustion. Internal temperatures of 250 ?350°C initiate a self-propagating internal reaction which results in foam ignition when the reaction reaches the foam surface. The stability of a polyurethane foam to such heating increases with the age of the foam.     

Caprolactam based block copolymers using polymeric activators

Caprolactam has been polymerised by sodium hydride in the presence of isocyanate terminated polymers. The latter participate in the initiation reaction and allow the preparation of materials where the prepolymer can amount to 50% of the product. There is evidence that block copolymers are formed, and the properties of polycaprolactam are considerably modified by the use of such activators. Styrene-butadiene or, particularly, caprolactone based isocyanates give materials having properties similar to the harder thermoplastic polyurethanes. The dependence of properties on the nature and amount of the polymeric activators, and the conditions of preparation and processing, have been investigated. Crystalline morphology has also been examined. Tensile strengths of 50 MN/m² with 550% elongation at break are readily attainable with these materials.     

Adaptation of the stochastic formulation of the surface rejuvenation model to turbulent convection heat transfer

In this paper the stochastic formulation of the surface rejuvenation model has been (1) used in the development of relationships for the mean temperature and velocity profile in terms of the mean residence time, mean approach distance, and approach distance distribution, and (2) coupled with appropriate estimates of these modeling parameters to provide quantitative predictions for the mean heat transfer as well as the temperature and velocity profiles. The effect of axial pressure gradient is also included.     

MCP-1, not MIP-1alpha, is the endogenous chemokine that cooperates with TGF-beta to inhibit the cycling of primitive normal but not leukemic (CML) progenitors in long-term human marrow cultures

The long-term culture (LTC) system has been useful for analyzing mechanisms by which stromal cells regulate the proliferative activity of primitive normal, but not chronic myeloid leukemia (CML), hematopoietic progenitor cells. In previous studies, we identified two endogenous inhibitors in this system. One is transforming growth factor-beta (TGF-beta), which is equally active on primitive normal and CML progenitors. The other we now show to be monocyte chemoattractant protein-1 (MCP-1). Thus, MCP-1, when added to LTC, blocked the activation of primitive normal progenitors but did not arrest the cycling of primitive CML progenitors. Moreover, the endogenous inhibitory activity of LTC stromal layers could be overcome by the addition of neutralizing antibodies to MCP-1, but not to macrophage inflammatory protein-1alpha (MIP-1alpha). However, neither of these antibodies antagonized the inhibitory activity of NAc-Ser-Asp-Lys-Pro (AcSDKP) on primitive normal but not CML progenitor cycling in this system. Moreover, none of six other -C-C- or -C-X-C- chemokines, previously shown to inhibit primitive normal human CFC proliferation in semisolid assays, were found to act as negative regulators when added to normal LTC. These results provide further support for the concept that primitive CML progenitor cell proliferation is deregulated when these cells are exposed to limiting concentrations of multiple inhibitors, only some of which have differential actions on normal and Ph+/BCR-ABL+ cells.     

Quantum chaotic transport in double barrier tunnel structures

The transition from regular to chaotic classical electron dynamics in a wide potential well with a high tilted magnetic field is investigated using Poincaré sections. The corresponding quantized energy level spectrum for the well is calculated as a function of the tilt angle π. For values of π where the system exhibits strong classical chaos, the distribution of nearest-neighbor level spacings obeys universal Wigner statistics. Regular long-range fluctuations in the density of levels are identified and related to distinct unstable closed classical orbits in accordance with the Gutzwiller trace formula. These orbits are found to produce regions of high probability density (scars) in the wavefunctions associated with subsets of almost equally-spaced energy levels. The energies of these scarred states can be located using a simple semiclassical quantization rule. This periodic scarring of individual wavefunctions is shown to have a pronounced influence on the tunneling characteristics of double barrier structures. Tunneling transitions into the scarred states dominate the current-voltage curves and generate a series of resonant peaks as observed in recent magnetotunneling experiments. Regimes in which resonant tunneling spectroscopy might provide experimental evidence for the existence of scarred states are identified.