bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytic Center Manifolds of Dimension One
Authors: Aulbach B. 
Published: May 2007

AbstractThe flow of a system of ordinary differential equations near an equilibrium point is completely determined by the flow restricted to a corresponding center manifold. Even for analytic equations center manifolds need not be analytic and therefore, in general, the flow on a center manifold cannot be described by an analytic equation. It is the main purpose of this paper to show that one‐dimensional center manifolds are analytic in the only case where analyticity is relevant. Thus, the generally lacking analyticity causes no problems, neither from a practical nor from a theoretical point of view. Furthermore sufficient conditions are given for the analyticity of center‐stable and center‐unstable manifolds.
Eine allgemeine Theorie der Dynamik elastoplastischer Schalen unter Berücksichtigung endlicher Verformungen
Authors: Serrano R. 
Published: May 2007

AbstractDie vorliegende Arbeit befaßt sich mit der Aufstellung einer allgemeinen geometrisch nichtlinearen Theorie der Dynamik dünner Schalen aus elastoplastischem Werkstoff. Für die elastischen Formänderungen wird das verallgemeinerte Hookesche Werkstoffgesetz herangezogen, während für den Zusammenhang zwischen Spannungsinkrementen und Verzerrungsgeschwindigkeiten innerhalb plastischer Formänderungen ein Formänderungsgesetz in Anlehnung an die Theorie des plastischen Potentials gewählt wird. Der Bereich elastischer Formänderungen wird gegenüber dem elastoplastischen mittels einer verallgemeinerten Huber‐Misesschen Fließbedingung abgegrenzt, die sowohl eine isotrope als auch eine anisotrope Materialverfestigung beschreibt. Die elastoplastischen Formänderungen werden als Summe von elastischen und plastischen Verzerrungsgeschwindigkeitsanteilen betrachtet.
Zur optimalen Steuerung in Dirichletschen Randbedingungen bei Evolutionsgleichungen
Authors: Kampowsky W. 
Published: May 2007

AbstractDie Arbeit beschäftigt sich mit Problemen optimaler Steuerung, die durch nichtlineare Rand‐Anfangswertprobleme für parabolische Differentialgleichungen 2m‐ter Ordnung beschrieben werden. Es werden Randsteuerungen mit Randbedingungen vom Dirichletschen Typ betrachtet. Das Rand‐Anfangswertproblem wird funktionalanalytisch verallgemeinert und als Anfangswertaufgabe für eine Evolutionsgleichung im Rahmen der Theorie monotoner Operatoren untersucht. Im wesentlichen werden notwendige Optimalitätsbedingungen hergeleitet, die aus einer allgemeinen Variationsungleichung und einer adjungierten Evolutionsgleichung bestehen. Der Fall von Randsteuerungen in Neumannschen Randbedingungen wird in einer späteren Arbeit [5] untersucht.
The Use of MACSYMA for Solving Elliptic Boundary Value Problems
Authors: Thejll P. , Gilbert R. P. 
Published: May 2007

AbstractIn this work we shall present a so‐called boundary method for solving an elliptic boundary value problem. As has been mentioned in the book of Herrera [14] there are two main approaches for the formulation of boundary methods. One is based on the method of integral equations and the other on the use of complete systems of solutions. We shall emphasize the second approach as the method of integral equations has been treated in Colton and Gilbert [5] and Gilbert and Linz [12].
Shifting Tendencies of a Balanced System with Equilibrium Zones
Authors: Klepp H. J. , Bischoff B. 
Published: May 2007

AbstractThe results of mathematical and experimental investigations of a multi‐body‐system in the form of a symmetric deformable parallelogram are presented. The system has friction affected constraints and possesses equilibrium zones. Under permanently acting disturbances the system migrates inside the equilibrium zones. In order to predict the system behaviour direction elements, direction fields and shifting tendency functions are defined. The computed results are in good agreement with the experimental data.
MHD Equilibria with Cusped Plasma‐Vacuum Interfaces
Authors: Kaiser R. 
Published: May 2007

AbstractThe free‐boundary MHD equilibrium is considered in the case of plane symmetry and constant current profile. We prove the existence of solutions in a neighbourhood of cusp singularities of the plasma‐vacuum interface. In both cases — the “plasma” and “vacuum cusps” — we derive a power law describing the asymptotic shape of the cusps; the allowed exponents are half‐integers. This leads to a natural classification of cusps. The solutions are classified accordingly and their asymptotic behaviour close to the cusp is found to depend only on the class to which the solution belongs.
On a Method of Weierstraß for the Simultaneous Calculation of the Roots of a Polynomial
Authors: Hopkins M. , Marshall N. , Schmidt G. , Zlobec S. 
Published: May 2007

AbstractWir beweisen einige neue Ergebnisse über eine Methode vom Newtonschen Typ, die ursprünglich auf Weierstraß zurückgeht, für die gleichzeitige Berechnung aller Wurzeln eines algebraischen Polynoms. Diese Methode hat bemerkenswerte lokale wie auch globale Konvergenzeigenschaften und könnte sowohl für Theoretiker als auch für Praktiker von Interesse sein.
General Multilayer Geometrically‐Exact Beams and 1‐D Plates with Piecewise Linear Section Deformation
Authors: Vu‐Quco L. , Ebcioǧlu I. K. 
Published: May 2007

AbstractA general theory of geometrically‐exact multilayer beams and 1‐D plates, which can be viewed as a special version of a Cosserat continuum, is presented. The formulation allows for shear deformation in each layer; the deformed cross section is piecewise linear such that interlayer continuity is exactly satisfied. Large deformation and large overall motion can be analyzed, as a salient feature of the geometrically‐exact formulation. The number of layers is unlimited, with the reference centroidal line arbitrarily chosen among the layers. The unique features of the present formulation provide a versatile model to investigate the behavior of an important class of composite/multilayer structure that have ply drop‐off, or that are connected together at any arbitrary layers. Also derived are two important particular cases of the general formulation: (i) The case in which only the reference layer undergoes finite rotations, whereas rotations in the outer layers are small relative to that of the reference layer, (ii) the fully linearized case.
Nonlinear Variational and Constrained Hemivariational Inequalities Involving Relaxed Operators
Authors: Verma R. U. 
Published: May 2007

AbstractAt first we consider the solvability of generalized nonlinear variational inequality (GNVI) problems involving relaxed operators using an iterative algorithm. Secondly, we apply relaxed operators to constrained nonlinear hemivariational inequality (CNHVI) problems.
On Continuum Modelling the Interphase Layers in Certain Two‐Phase Elastic Solids
Authors: Dell'Isola F. , Wozniak C. 
Published: May 2007

AbstractIn this paper we propose a continuum model of a moving transition layer smoothly separating two different solid phases of a certain elastic material continuum and we investigate some necessary conditions to its existence and propagation. An application of this model to the analysis of wave propagation in micro‐damaged media with open‐ and closed‐micro cracked phases is shown.
Natural Convection Boundary Layer Flow of a Micropolar Fluid
Authors: Hassanien I. A. , Bakier A. Y. , Gorla R. S. R. 
Published: May 2007

AbstractWe examine theoretically the steady free convection in micropolar fluids. Four different flows, namely, those about a vertical isothermal surface, vertical surface with uniform heat flux, a plane plume and a wall plume are considered in the paper. Numerical solutions for the governing equations are presented, for a range of values of the material properties and Prandtl number of the fluid.
Paper chromatographic determination of trimethyloctadecyl quaternary ammonium chloride in dimethyldioctadecyl quaternary ammonium chloride
Authors: Moyer Frances , Nelson James , Milun Albert 
Published: May 2007

AbstractA quantitative paper chromatographic method was worked out for determining small amounts of trimethyloctadecyl quaternary ammonium chloride in dimethyldioctadecyl quaternary ammonium chloride. With a mixed solvent containing methanol, acetone, and water, the trimethyl‐type quaternary travels just behind the solvent front, whereas the dimethyl‐type quaternary and other components move very little. The trimethyl quaternary spot is developed with bromphenol blue and the resulting color is measured photometrically at 607 mμ. Standards are run on either side of the sample spot and are used for quantitative calibration. Accuracy and reproducibility of the method appears to be within 0.4% absolute.
Fats in human nutrition
Authors: Kummerow F. A. 
Published: May 2007

SummaryDietary fats represent the most compact chemical energy available to man. They contain twice the caloric value of an equivalent weight of sugar. However dietary fats should not be thought of solely as providers of unwanted calories as fats are as vital to cell structure and biological function as protein. If an individual consumes food items of high fat content, an adequate protein and vitamin intake should be assured in order to provide the lipotropic factors necessary for normal fat metabolism. It may be more judicious to control the total caloric intake under such circumstances rather than to resort to periods of semi‐starvation or to drastically decrease the dietary fat intake which could result in an increase in hunger pangs and an actual increase in total caloric intake. If the excess calories furnished by carbohydrates are converted to fatin vivo, the problem of obesity could not be solved under conditions of increased total caloric intake. The problem could be solved by a curtailed intake of a diet which includes meat, milk, eggs, vegetables, fruits, and sufficient cereals and bread to provide for an adequate protein, vitamin, and caloric intake. Dietary fats provide the essential linoleic acid which seems to have both a structural and functional role in animal tissue. Although the optimum total intake of linoleic acid by man has not been established, it is evident that the level of intake in the American dietary pattern could be increased. However the indiscriminate substitution of soft for hard fats seems undesirable as an excess consumption of highly unsaturated fatty acids may change the functional value of the triglycerides in the depot fats and may put an undue stress on the antioxidant supply availablein vivo.
Stabilization of edible animal fats during rendering
Authors: Sims Rex J. , Lee Hilfman 
Published: May 2007

SummaryStudies have shown that lard and edible beef fats can be stabilized effectively with phenolic antioxidants during pressure steam‐rendering. Best results were obtained for a given stabilizer level with the individual phenolics butylated hydroxyanisole and butylated hydroxytoluene. Poorer results were obtained with the mixtures in propylene glycol.
Alcoholic extraction of vegetable oils. III. Solubilities of babassu, coconut, olive, palm, rapeseed, and sunflower seed oils in aqueous ethanol
Authors: Rao Rama Kanth , Arnold Lionel K. 
Published: May 2007

SummarySolubilities of babassu, coconut, olive, palm, rapeseed, and sunflower seed oils in aqueous alcoholic solutions at various temperatures were determined by a direct and simple method. Solubility curves for the six oils are presented.The critical solution temperatures increase with the water content of the alcohol, and in each case the relationship is linear. The pressure in the system also varies with the temperature, the maximum being about 20 p.s.i.g.
Determination of tocopherol in autoxidizing methyl esters of fatty acids
Authors: Lips H. J. 
Published: May 2007

SummaryAutoxidizing methyl esters of fatty acids interfered with the determination of α‐tocopherol by ultraviolet spectrophotometry or by the bipyridine colorimetric method. Interference with the colorimetric method was removed by sulfuric acid treatment, but spectrophotometry was applicable only when the tocopherol was completely separated from oxidized fat. This separation could not be obtained by sulfuric acid treatment but was accomplished by room temperature saponification in an alcohol‐petroleum ether system protected by pyrogallol. The sensitivity of the spectrophotometric method was increased by oxidizing tocopherol quantitatively to thep‐quinone with 2N nitric acid.
Some effects of ionizing radiations on lipids. I. Monocarbonyl production in vegetable oils
Authors: Lang David A. , Proctor Bernard E. 
Published: May 2007

Summary and ConclusionsIrradiation of refined vegetable oils by high‐energy cathode rays resulted in the production of monocarbonyl compounds. The yield was about 0.2 µM per gram per 106 rep. for doses up to about 107 rep. Some of the products were themselves sensitive to the radiations, and the net yield was dependent upon a function of the concentrations and reactivities of the precursors and of the end‐products.Concurrently with the formation of the monocarbonyls there was an attack on the conjugated triene systems in the media and an increase in ultraviolet absorption in the 225–240 mµ region. However the irradiation products resulted from other mechanisms in addition to those involving the trienes.Irradiation under reduced temperature or in vacuum or with the addition of antioxidants did not decrease the yield of monocarbonyl compounds. However the use of a vacuum and the inclusion of antioxidants were partially effective in reducing the irradiation attack on triene groups.The net yields of monocarbonyls were dependent upon the concentrations and sensitivities of the products as well as of their precursors. Thus, although methods commonly successful in inhibiting oxidations of oils did not reduce these yields, they did suppress some irradiation‐induced reactions, particularly those involving unsaturated compounds. In this respect their action was similar to that which has been demonstrated in inhibition studies of antioxidations in oils.
Reactions of conjugated fatty acids. III. Kinetics of the Diels‐Alder reaction
Authors: Gast L. E. , Bell E. W. , Teeter H. M. 
Published: May 2007

SummaryThe kinetics of a Diels‐Alder‐type reaction between diethylazodicarboxylate andt,t‐9,11‐octadecadienoic acid has been studied in various solvent systems and with acidic catalysts. The rate of the reaction was found to vary as follows: a) the reaction rate is faster in polar solvents than in nonpolar solvents; b) addition of acidic catalysts to nonpolar solvents increases the rate of the reaction, and acidic catalysts appear to have no effect on the rate of reaction in polar solvents; c) when compatibility can be maintained, addition of water to polar solvent systems appears to increase the reaction rate in proportion to the amount of water added.The reaction follows second‐order or pseudo second‐order kinetics. Probably it is more complex than the over‐all reaction kinetics indicate. Certain reactions were studied at two temperatures, and information on activation energy of the reaction has been obtained.
Polarized infrared spectra of some crystalline fatty acids
Authors: Susi H. , Smith Anne M. 
Published: May 2007

SummaryPolarized infrared spectra of thin films of representative samples of form C′, B′, and A′ n‐alkyl monocarboxylic acids have been observed. The data obtained on C′ heptadecanoic acid confirm that the type C and type C′ structures are very similar and that the major difference is in the packing of the CH3 end‐groups. The results on type B′ and A′ acids indicate that meaningful polarization data can be obtained on triclinic crystals of n‐alkyl carboxylic acids, provided that careful consideration is given to the sample orientation and to the symmetry characteristics of certain portions of the molecules. The P1 space structure of these crystals and the orthorhombic substructure of the B′ configuration as well as the triclinic substructure of the A′ configuration were confirmed. Some strong infrared bands of the highly irregular triclinic A′ structure did not seem to be appreciably polarized. The data on group‐frequency bands which did show clear‐cut polarization were in agreement with prediction. The spectra of form A′, B′, and C′ crystals did not coineide with data obtained on KBr pellets. It is concluded that in these pellets fatty acids exist in a form which is not easy to duplicate under more conventional conditions.
Surface‐active properties of sodium salts of sulfated fatty acid monoglycerides
Authors: Biswas A. K. , Mukherji B. K. 
Published: May 2007

SummarySodium salts of fatty acid monoglyceride sulfates have been prepared by sulfating purified monoglycerides with chlorosulfonic acid or a pyridine‐sulfur trioxide complex and subsequent neutralizing. Surface tension, interfacial tension, wetting, suspending and foaming characteristics, calcium stability, and emulsifying property (including stability of the emulsion obtained) of the aqueous solution of these surfactants from C12, C14, C16, and C18 saturated fatty acids and from oleic acid and linoleic acids have been determined and evaluated.With the exception of the wetting characteristic which was found to be optimum in the case of the more hydrophilic products (like those from lauric and linoleic acids) the remaining properties were found to reach a maximum value when the hydrophilic‐hydrophobic balance in the surfactant molecule was seemingly optimum, as attained by myristic and oleic acid products.
The occurrence of the chick pericardial edema factor in some oleic acids and products derived therefrom
Authors: Ames Stanley R. , Swanson William J. , Ludwig Marion I. , Brokaw George Y. 
Published: May 2007

SummaryA number of samples of commercially‐prepared (U.S.P.) oleic acids and glycerol esters of oleic acids were shown to contain a material which produces pericardial edema in chicks. The active material was concentrated from either the oleic acid or the glycerol mono‐ester by molecular distillation.Four of the 11 samples of oleic acid were inactive; this indicates that the pericardial edema is not caused by the fatty acid itself but by an incidental material in the fatty acid.
The aliphatic alcohols of wool wax. V. Studies in Waxes
Authors: Murray K. E. , Schoenfeld R. 
Published: May 2007

SummaryTen branched chain alcohols have been isolated from the unsaponifiable part of wool wax and identified. They comprise the dextro‐rotatory ante‐iso alcohols of odd carbon number, C17 to C27, and the iso alcohols of even carbon number, C20 to2626.
Pyrogallol derivatives as antioxidants for carotene
Authors: Bickoff E. M. , Coppinger G. M. , Livingston A. L. , Campbell Tod W. 
Published: May 2007

ConclusionsCertain derivatives of pyrogallol have been shown to possess marked activity as antioxidants for carotene in some systems while they are of little value in others. Thus all the derivatives which are more effective than pyrogallol in protecting carotene in mineral oil are very much less effective than pyrogallol in lard and, with two exceptions, are also less effective in coconut oil. Neither pyrogallol nor any of its derivatives tested were effective antioxidants for carotene in alfalfa meal. Insufficient data are available to permit conclusions regarding relationships between changes in antioxidant activity and minor structural variations.
A review on petroselinic acid and its derivatives
Authors: Placek Lida L. 
Published: May 2007

AbstractThis publication contains a comprehensive review of literature on petroselinic acid and its derivatives. All known sources of petroselinic acid including its synthetic derivation have been explored and described. The different plant species, whose seeds offer an oil reported to contain petroselinic acid, have been listed and the amounts of oil and their prevalent fatty acid components given. Its method of isolation from the naturally occurring triglycerides and identification have been discussed. The descriptions of characteristics and properties of petroselinic acid and its various derivatives are also included. In many cases they have been compared to oleic acid and other related fatty acids and their derivatives. The various methods of chemical modification of petroselinic acid have been, investigated and the derivatives obtained have been summarized in tabular form. Some potential uses for petroselinic acid and the products obtained from it have also been discussed. This review was designed to show that is known about petroselinic acid to date, and perhaps to create further interest in research on this unique naturally occurring octadecenoic acid.
A comparison of the effects of the polyunsaturated fatty acids of cuttlefish liver oil and cottonseed oil on cholesterol metabolism
Authors: Kaneda T. , Alfin‐Slater R. B. 
Published: May 2007

AbstractRats red ad lib. for 12 weeks either a fat‐free diet, a diet containing 15% cottonseed oil, or a diet containing 15% cuttlefish liver oil, with or without exogenous (1%) cholesterol, were studied to evaluate and compare the effect of polyunsaturated fatty acids of cuttlefish liver oil and cottonseed oil on cholesterol metabolism. The results indicate that the longer chain polyunsaturated fatty acids contained in the fish oil cannot substitute for the essential fatty acid, linoleic, either as far as effect on various aspects of cholesterol metabolism are concerned or in the ability to form arachidonic acid. The observed interference of cuttlefish liver oil with the absorption of exogenous cholesterol may be caused by the presence in this oil of the highly unsaturated long chain fatty acids.
Factors influencing the formation of complexes between oxidized lipids and proteins
Authors: Narayan K. A. , Kummerow F. A. 
Published: May 2007

AbstractComplexes were formed between egg albumin and oxidized lipids, such as thermally oxidized corn oil and autoxidized linoleic acid, under a standardized set of conditions. No complex could be obtained under these conditions when lysine, glycine, bactopeptone, gelatin or sodium caseinate were substituted for egg albumin. Lactalbumin was equally as reactive, casein much less and fresh egg white superior to egg albumin in their complexing ability with oxidized corn oil. As the time of reaction was increased, the amount of the complex formed also increased. Optimum complex formation took place at a concentration of 1% protein, a pH of 7 and 60C. The ease of formation of these complexesin vitro indicated that similar complexing could readily take placein vivo under suitable pathological conditions.
Comparative analytical studies of fatty acids of the algaChlorella pyrenoidosa
Authors: Schlenk Hermann , Mangold H. K. , Gellerman J. L. , Link W. E. , Morrissette R. A. , Holman R. T. , Hayes H. 
Published: May 2007

AbstractGas‐liquid chromatography, several versions of paper chromatography, and alkaline isomerization have been applied to one preparation ofChlorella fatty acid methyl esters.GLC outranks other methods in rapidity, reproducibility, and resolving power. The presence of nonvolatile components in the sample can lead to erroneous results. Among PC methods which might arise from autoxidation and polymerization are detected. Esters or acids with 14 or fewer C atoms should be analyzed as nonvolatile derivatives. AI, as used here, introduces a systematic error in the determination of linoleic and linolenic acids.The quantitative results of the methods are in agreement for the major components, which all belong to the C10 and C18 series.A number of minor components have been revealed by GLC and/or PC. They are tentatively identified as <C12, C12, four C14, C15, two C17, C19, three C20, two C22, and C24 acids. Several of these compounds have been found independently by different methods in hydrogenated form or as radioactive esters. This enhances the certainty of their identification. Eurichment by fractional distillation was essential for their detection. Possible losses in their distillation and other considerations make uncertain the assay of most of the minor components by GLC or PC.