bluuebunny/crossref_metadata_2025_split huggingface dataset:
Eine exakte Lösung des Problems der optimalen Randwertsteuerung für eine Klasse örtlich verteilter Systeme
Authors: Knöpp U. 
Published: June 2007

AbstractFür die Aufgabe, einen eindimensionalen Wärmeleiter über eine Randbedingung optimal zu steuern, wird eine exakte Lösung hergeleitet. Vorausgesetzt ist ein quadratisches Kostenfunktional, das ein unendliches Zeitintervall berücksichtigt. Die Lösung stützt sich auf eine Arbeit von Aliferow und Egorow, die das Optimierungsproblem auf ein unendliches algebraisches Gleichungssystem zurückführen. Im vorliegenden Aufsatz wird gezeigt, daß dieses Gleichungssystem exakt lösbar ist. Die optimale Steuerfunktion wird explizit angegeben, und diese Lösungsformel wird diskutiert.
Stress and Couple‐Stress Fields Produced by Circular Dislocations in an Isotropic Elastic Micropolar Continuum
Authors: Minagawa Sitro 
Published: June 2007

AbstractThe elastic fields produced by discrete dislocations in an infinitely extended isotropic micropolar continuum are calculated from the author's theory (cf. [1]). The expressions for the stress and couple‐stress fields produced by circular dislocations are derived. They are specialized to those for the fields produced by infinitesimal loops. For loops of finite radii, numerical estimations are carried out to investigate the stress and couple‐stress fields in the close vicinity of those loops. The results are plotted on the figures.
Zum Druckberg in der Magneto‐Gasdynamik
Authors: Hölder E. 
Published: June 2007

AbstractIn der Gasdynamik ist A. Busemann's Druckberg gerade die Figuratrix des zugehörigen Variationsproblems. Auf die Magneto‐Gasdynamik konnte ich das bereits früher übertragen [4c,d]. Dabei fehlte aber noch der Nachweis der Parallelität der sich entsprechenden Flächenelemente der Strömungsfläche und des „Druck‐Magnetberges”︁. Dieser geht im Fall der ebenen Strömung aus dem Busemannschen einfach durch eine Lie'sche Berührungstransformation hervor. Bei den Machschen Wellen bleiben nur zwei übrig, wenn man — etwa beim Anfangswertproblem — eine in den Gleichungen und im Variationsproblem auftretende, auf jeder Stromlinie konstante Funktion m(Ψ) festhält; das ist eine Vereinfachung.
Ein hinreichendes Kriterium für die Durchführbarkeit des Intervall‐Gauss‐Algorithmus bei Intervall‐Hessenberg‐Matrizen ohne Pivotsuche
Authors: Reichmann Karl 
Published: June 2007

AbstractEs wird eine Klasse von Intervall‐Hessenberg‐Matrizen angegeben, bei der der Intervall‐Gauss‐Algorithmus ohne Pivotsuche durchführbar ist. Anschließend wird gezeigt, daß unter einigen schwachen Voraussetzungen an die Maschinenrundung diese Eigenschaft auch bei der Berechnung mit einem Komputer erhalten bleibt. Das Kriterium wird mit zwei bekannten Kriterien von Alefeld und Herzberger bzw. Barth und Nuding verglichen.
Mehrdimensionale Spline‐Interpolation und ableitungsfreie Fehlerabschätzungen bei nichtlinearen parabolischen Differenzenverfahren
Authors: Böther Hans‐Heinrich 
Published: June 2007

AbstractGegenstand dieser Arbeit ist die Realisierung ableitungsfreier Fehlerabschätzungen für nichtlineare parabolische Differenzenschemata. Die diskreten Näherungswerte ergänzen wir mittels eines speziellen n‐kubischen Polynom‐Splines zu einer stückweise glatten Funktion und weisen nach, daß nach Addition einer leicht zu berechnenden Korrekturfunktion und nach Anwendung einer Verallgemeinerung des Lemmas von Nagumo‐Westphal die Summe aus Spline und Korrekturfunktion eine obere bzw. untere Schranke der gesuchten Lösung ist. Für die so berechneten Schrankenfunktionen werden Konvergenzsätze bewiesen.
Integral Representations in Couple Stress Theory of Fluids
Authors: Ramkissoon H. 
Published: June 2007

AbstractThe system of differential equations characterizing the slow, steady, incompressible flow of couple stress fluids is examined. Integral representation for the velocity vector is obtained with the aid of a constructed fundamental singular solution and a derived reciprocity theorem. The very form of this integral representation suggests the introduction of potentials whose properties are stated. Matrix Green's functions are then introduced and the formal solutions to two types of boundary value problems are expressed by integral representations involving these functions, given body forces and surface data.
Implizit definierte orthogonale Polynome
Authors: Engels H. 
Published: June 2007

AbstractBei den klassischen Orthogonalpolynomen ist die Gewichts‐oder Belegungsfunktion unabhängig von den dazu gehörenden orthogonalen Polynomen. Es wird in der vorliegenden Arbeit gezeigt, daß es orthogonale Polynomsysteme auch dann noch geben kann, wenn die Gewichtsfunktion von ihnen abhängt. Dabei geht i. a. die Eindeutigkeit verloren während einige Minimaleigenschaften analog zur Theorie klassischer Orthogonalpolynome erhalten bleiben. Anwendungen findet man in der Theorie der Quadraturformeln.
Spectral Representation of Stresses Near a Cylindrical Cavity in an Elastic Half‐Space Loaded by Rayleigh Surface Waves
Authors: Höllinger F. , Ziegler F. 
Published: June 2007

AbstractThe linear elastodynamic problem of a halfspace with a circular cylindrical cavity, parallel to the free surface, is considered for the case of a Rayleigh surface wave loading. Reflections of the P‐ and S‐wave systems at the cavity surface are described exactly, whereas reflections at the plane free surface of the halfspace are approximated. For this purpose the plane surface is replaced by a cylindrical surface of small curvature. Using a Fourier series expansion in the polar angle of all waves, including the incident Rayleigh wave, the solution is given in terms of cylindrical waves. By means of this procedure it is relatively simple to numerically calculate the power spectra of the stresses in the near field around the cavity.
Zur Existenz und Eindeutigkeit der Görtler‐Funktionen II. Das Existenzproblem
Authors: Schwierz K. P. 
Published: June 2007

AbstractWie in Teil I des vorliegenden Aufsatzes (siehe [25]) sei die ebene und stationäre Strömung einer inkompressiblen und reibenden Flüssigkeit in einer laminaren Wandgrenzschicht gegeben. Zur Berechnung dieser Strömung wurde in [3], [4] und [18] die Görtler‐Reihe eingeführt. Die Koeffizientenfunktionen dieser Reihe sind die Lösungen eines unendlichen Systems von gewöhnlichen Randwertaufgaben dritter Ordnung, die von unendlich vielen Strömungsparametern abhängen. Nach [24] führt ein linearer Ansatz für die Koeffizientenfunktionen der Görtler‐Reihe auf ein zweifach unendliches System von Randwertaufgaben für die Ansatzfunktionen. Diese Randwertaufgaben hängen nur noch von einem einzigen Strömungsparameter ab. Die Ansatzfunktionen sind in der Literature unter dem Namen „Görtler‐Funktionen”︁ bekannt. – In Teil I des vorliegenden Artikels wurde die Eindeutigkeit der Görtler‐Funktionen bewiesen. Im hier folgenden Teil II wird ein Existenzsatz mit asymptotischen Aussagen angegeben. Dazu werden die Randwertaufgaben umgewandelt in Fixpunktaufgaben in einem geeigneten Funktionenraum. Für diese Fixpunktaufgaben liefert der Fixpunktsatz von Schauder und Tychonoff einen Fixpunkt.
Galerkin‐Differenzenmethode zur Lösung zweidimensionaler Boussinesq‐Gleichungen
Authors: Prochnow D. 
Published: June 2007

AbstractDie Methode der Herleitung extern konvergenter Differenzenschemen aus Galerkin‐Verfahren mit Hilfe schwach konformer h‐lokaler Basiselemente wird bei der näherungsweisen Lösung zweidimensionaler Boussinesq‐Gleichungen untersucht.
Interaction of Torsional Wave by Penny‐shaped Crack at the Interface of Two Bonded Dissimilar Elastic Solids
Authors: Srivastava K. N. , Palaiya R. M. , Karulia D. S. 
Published: June 2007

AbstractThe paper deals with the problem of finding the stress distribution near a penny‐shaped crack located at the interface of two bonded dissimilar elastic solids. The crack is opened by the interaction of a torsional wave incident normally on the crack. The problem is reduced to the solution of a Fredholm integral equation. Iterative and numerical solutions of the solutions of this equation have been obtained. The solution is used to calculate the stress‐intensity factor. The results with those of Mal for homogeneous medium.
Diskretisierungsfehler und Defektkorrekturen bei der Lösung von Gleichungen in Banach‐Räumen
Authors: Lippold G. 
Published: June 2007

AbstractEs ist üblich, Diskretisierungsfehler durch den Defekt in Gleichungen höherer Genauigkeit und die Lösung benachbarter Gleichungen zu schätzen. Wir zeigen, wie sich diese Techniken aus der Idee des Verfahrens der Nachiteration ableiten lassen, und geben ein Extrapolationsverfahren für lokale Diskretisierungsfehler in Gleichungen zweiter Art an.
Strömung eines magnetfeldfreien Plasmas im Rahmen der Zweiflüssigkeitstheorie
Authors: Förste J. 
Published: June 2007

AbstractDie Strömung eines magnetfeldfreien Plasmas wird durch hydrodynamische Gleichungen beschrieben. Unter geeigneten Anfangs‐ und Randbedingungen werden Existenz‐ und Einzigkeitsaussagen gemacht.
Effects of Mass Transfer and Free Convection Currents on the Oscillatory Flow Past an Infinite Vertical Porous Plate with Constant Suction and Heat Flux
Authors: Soundalgekar V. M. , Gupta S. K. 
Published: June 2007

AbstractUnsteady flow of a binary fluid past an infinite, porous, vertical plate has been analysed on taking into account (1) constant suction velocity (2) oscillating free stream (3) constant heat flux at the plate (4) presence of a foreign mass. Approximate solutions to coupled non‐linear equations are derived. Effects of various parameters like Gr (Grashof number), Gm (modified Grashof number), E (Eckert number), Sc (Schmidt number) and ω (frequency) on the velocity and temperature are discussed.
Plastische Deformationsgesetze in differentieller Standardformulierung
Authors: Bergander H. 
Published: June 2007

AbstractAnsätze aus der Literatur zur Beschreibung aller Verfestigungstypen werden in eine einheitliche Standardformulierung (8) gebracht. Diese ist der Sonderfall eines allgemeinen Vorschlages des Autors für inelastisches Material [3]. Die Auswahl der Verfestigungsgesetze wird auf Folgefließflächen des Types der quadratischen Formen beschränkt. Die Standardformulierung wird in der Mehrzahl allein durch Umformung, in speziellen Fällen durch sinnvolle Approximationen erreicht.
Additional physical properties of diglyceride esters of succinic and adipic acids
Authors: Feuge R. O. , Ward T. L. 
Published: June 2007

SummaryDiglycerides of the fat‐forming acids yield, on esterification with succinic, adipie, and other shortchain dibasic acids, a poteutially useful series of compounds ranging from hard, high‐melting waxes to viscous oils which will not crystallize. A number of the properties of these compounds were determined in carlier investigations.In the present investigation additional properties of the 1,3‐diolein and 1,3‐distearin esters of succinic and adipic acids were determined. Surface and interfacial tensions were measured and found to be similar to those of cottonseed oil. The smoke points also were found to be similar to that of cottonseed oil. The ability of the compounds to thicken cottouseed oil was measured and found to be somewhat better than that of highly hydrogenated cottonseed oil at levels above about 12%, and the mixtures were relatively resistant to fat leakage. In hardness the distearin esters of succinic and adipic acid were comparable to carnauba wax and were over twice as hard as highly hydrogenated cottonseed oil. Permeability to water vapor was found to be greater than that of highly hydrogenated cottonseed oil and carnauba wax and about equal to that of cocoa butter.
Tung oil derivatives as plasticizers for buna‐N rubber
Authors: Placek Lida L. , Pastor H. P. , Hughes J. P. , Bickford W. G. 
Published: June 2007

SummaryEight derivatives of tung oil, namely, the methyl vinyl ketone, dimethyl maleate, methyl acrylate, and acrylonitrile adducts, and their hydrogenated products, were prepared and screened as softeners for Buna‐N rubber with dibutyl sebacate, as the control. Five of the eight products evaluated yielded stocks that met the low‐temperature flexibility requirements (−40°C.) of the automotive industry. In all cases the stocks prepared from the unhydrogenated derivatives were superior in plasticizing efficiency to the stocks prepared from their hydrogenated counterparts or to those prepared from the control.
Recording apparatus for measuring oxygen absorption
Authors: Lancaster E. B. , Bitner E. D. , Beal R. E. 
Published: June 2007

SummaryTwo sensitive but inexpensive electrical circuits have been described which translate change in mercury level in a manometer to an electromotive force of sufficient magnitude so that it may be applied to a standard d.c. potentiometric recorder. The recording manometer, when coupled with a simple closed system containing a small amount of lipid material and oxygen or air, can be adapted to determine continuously the cumulative absorption of oxygen by the oil or fat. The break‐point, a measure of the stability of the sample, may be obtained from the resulting curve. The apparatus has been successfully employed to determine the oxidative stability of hydrogenated soybean oil, and because of the small amount of attention required, it should be readily adaptable to quality control of edible oil and fat products. The recording manometer should be useful also for measuring and recording pressure changes in other systems.
Fractionation of heat‐bodied linseed oil with urea and acetone
Authors: Mehta T. N. , Sharma S. A. 
Published: June 2007

SummaryDuring heat‐bodying of linseed oil at 300°C. the drop in iodine value is high in the initial stages, without a corresponding increase in molecular weight. These changes are due partly to conjugation and partly to intradimerization and cyclization. However the amounts of conjugation (5 to 6%) and intradimerization (3 to 7%) are insufficient to explain the large drop in iodine value. Cyclization of linolenic acid takes place to the extent of 8 to 17% at the earlier stages of polymerization and hence is the principal cause of the large drop in iodine values. This cyclized product of linolenic acid was isolated by urea and characterized by determinations of saponification value, iodine value, and mean molecular weight.
Fatty acid vinyl esters as acylating agents: A new method for the enzymatic synthesis of monoacylglycerols
Authors: Bornscheuer Uwe T. , Yamane Tsuneo 
Published: June 2007

AbstractLipase‐catalyzed synthesis of monoacylglycerols (MAG) was performed by transesterification reactions between fatty acid vinyl esters and either glycerol (1) or 1,2‐O‐isopropylidene‐rac‐glycerol (2), without solvents or in the presence ofn‐pentane. Vinyl decanoate, vinyl laurate, vinyl stearate and vinyl palmitate have been converted to the corresponding monoacylglycerols. As expected for the reaction with1, a mixture of mono‐, di‐ and triacylglycerols was synthesized. The highest concentrations of MAG were achieved with vinyl stearate (30% 2‐MAG and 15% 1‐MAG). The reactions of fatty acid vinyl esters with the protected glycerol (2) led to the corresponding protected 3‐monoacylglycerols with 100% conversion after short reaction times. The subsequent cleavage of these acetonides was performed by four different methods. The fastest cleavage was found with trifluoroacetic acid as catalyst, whereas the highest concentration of MAG (100%) was obtained for the boric acid‐catalyzed hydrolysis of the acetonides.
A method for the determination of linoleic acid and conjugated dienoic acids in materials containing eleostearic acids
Authors: O'Connor R. T. , Heinzelman D. C. , Pack F. C. , Planck R. W. 
Published: June 2007

SummaryA procedure has been described which extends the scope of the spectrophotometric method for polyun‐saturated acids to the determination of linoleic and conjugated acids in the presence of large quantities of conjugated trienoic acids.Basis for the proposed method rests on equations which are offered to correct the “end” or “back‐ground” absorption of the highly absorbing triene conjugated acids at 233 mμ, the position of maximum absorption of conjugated dienoic acids and alkali isomerized linoleic acids. The method is limited to samples which do not contain nonconjugated trienoic acids (linolenic acids).The method has been tested by the analysis of several mixtures of cottonseed and dehydrated castor oils of known composition, to which varying amounts of alpha, beta, and mixtures of alpha‐ and beta‐eleostearic acids have been added. These samples have been used to demonstrate the application of the proposed method for the determination of dienoic conjugated acids, alpha‐eleostearic acid, beta‐eleostearic acid linoleic acid, oleic acid, and total saturated fatty acids.Comparisons of the results obtained with similar values, calculated from the known composition of the mixtures, prove that the proposed method gives reasonable results. Standard deviations between determined and calculated results vary from 0.36 for diene conjugated acids to 1.40 for oleic acid.The method has been applied to the analysis of foreign and domestic tung oils.
Some factors influencing foam stability
Authors: Sporck C. R. 
Published: June 2007

SummaryIt is believed that liquid films owe their stability to the Gibbs elasticity. How this elasticity may arise is discussed, and it is concluded that in some cases a nonequilibrium value may be the important concern. Some data on surface composition from radiochemical experiments and foam fractionation are presented. Finally an explanation of the origin of the slow and fast draining films of Ross, Miles, and Shedlovsky is offered.
Present status of the filtration‐extraction process for cottonseed
Authors: Spadaro J. J. , Vix H. L. E. , Gardner H. K. , D'Aquin E. L. , Eaves P. H. , Gastrock E. A. 
Published: June 2007

SummaryImprovements and refinements in the process for filtration‐extraction of cottonseed resulting from further pilot‐plant development studies are described as well as their adaptation to the first commercial plant. These improvements which depict the present status of the process for cottonseed include principally certain modifications in the method of conditioning of the meats or flakes prior to cooking and in the procedure for crisping; selection of best conveyor type for conveying cooked material over relatively long distances without objectionable comminution; selection of filter medium combining the desired properties of durability, non‐fouling, and low fines retention; determination of optimum filter‐cake thickness; and development of a method for clarification of the product miscella by continuous recycling through the formed cake on the filter. Also discussed is the quality and color stability of the oil produced from comparable lots of cottonseed by the filtration‐extraction process, as compared with that by hydraulic pressing, and by solvent extraction of uncooked flakes.
Tocopherol retention in oils aerated in glass and iron tubes
Authors: Luckmann Frederick H. , Melnick Daniel 
Published: June 2007

SummaryAeration of vegetable oils according to a modified A.O.M. test, involving the substitution of iron tubes for the conventional glass tubes, results in a more rapid destruction of the tocopherols present. Isopropyl citrate esters, predominantly monoisopropyl citrate, greatly retard the rate of tocopherol loss by sequestering soluble iron and by protecting the oil against further tocopherol loss by minimizing the effect of contact metal catalysis. Adsorption of tocopherols on the metal wall is insignificant.
Uranyl soaps
Authors: Bhandari A. M. , Dubey S. , Kapoor R. N. 
Published: June 2007

AbstractUranyl soaps (laurate, myristate, palmitate and stearate) were prepared by reaction of aqueous solutions of uranyl chloride and the corresponding sodium soaps. Viscosity and conductivity of the laurate, myristate and palmitate dissolved in dimethylformamide were measured.
Analytical method for determing copper in edible shortenings and oils
Authors: Deck Rudolph E. , Kaiser Kay K. 
Published: June 2007

AbstractA reliable, practical method was developed for the quantitative determination of sub‐ppm levels of copper in edible shortenings and oils. Copper is quantitatively extracted with a boiling solution of 0.01% EDTA in 25% HCl. The extract was analyzed with 2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline (Bathocuproine), a highly specific and exceptionally sensitive reagent for the colorimetric determination of copper. An average recovery of 99.8% was obtained on 22 samples containing added oil soluble copper standards. A standard deviation of 0.002 ppm was established at the 0.05 ppm level during routine application of this method to a variety of shortenings and oils.
Investigation of the phase behavior ofCruciferae seed oils by temperature programmed X‐ray diffraction
Authors: Riiner Ü. 
Published: June 2007

AbstractThe phase behavior of the seed oils from different strains ofBrassica napus, Brassica campestris, Sinapis alba, Crambe abyssinica andErysimum orientale is reported. The rapeseed oils and white mustardseed oils include products from plant breeding work in Canada and Sweden. The experimental technique includes the continuous recording of X‐ray diffraction patterns vs. temperatures between −50 C and complete melting of the most stable solid phases with a new DPT (Diffraction‐Pattern‐Temperature) camera. The crystallization and melting of oils with an erucic acid content above 8% can be described in terms of the polymorphic phases α, β2 and β1 (in the order of increasing stability). The designation β2 is tentative as the phase cannot be classified unambiguously by X‐ray diffraction data alone. The phase transition temperatures for a certain species form continuous functions of the erucic acid content, thus providing a basis for the prediction of some of the properties that are relevant for the utilization of the oils in the food industry.
Diol diricinoleates from dihaloalkanes
Authors: Lyon C. K. , Garrett V. H. 
Published: June 2007

AbstractA series of alkanediol diricinoleates was prepared by heating ricinoleic acid with triethylamine and dibromo‐ or dichloroalkanes containing 2 to 10 carbon atoms. As expected, the dibromides react more rapidly than the dichlorides. This method of esterification avoids the side reaction of estolide formation which occurs when ricinoleates are prepared by direct esterification or transesterification. The products are high molecular weight diols which should be useful in the preparation of polyurethanes.
Design and operation of a commercial soybean‐oil refining plant, using acetic anhydride as a degumming reagent
Authors: Myers Noel W. 
Published: June 2007

SummaryThe 50 oil process has been demonstrated on a commercial scale to be physically possible and economically attractive to refiners of soybean oil. The flavor and stability characteristics of the finished oil are identical to the conventional caustic‐refined product.
Identification of some marine oil constituents by chromatography
Authors: Sorrels Mary Frances , Reiser Raymond 
Published: June 2007

Summary and ConclusionA scheme for the separation and identification of some constituents of marine oils was developed. A preliminary separation on a silicic acid column with five solvent systems was followed by further separation and identification on silicic acid impregnated glass‐fiber filter paper. This method can be used successfully for qualitative determinations, but the irregularities in the density of the glass paper prevent an accurate quantitative assay.