bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quasioptimalität der Finite‐Elemente‐Methode bei nichtlinearen elliptischen Differentialgleichungen
Authors: Louis A. 
Published: June 2007

AbstractQuasioptimale Lp‐Fehlerabschätzungen im Sinne von Nitsche [10] werden angegeben für Galerkin‐Lösungen quasilinearer, elliptischer Differentialgleichungen 2m‐ter Ordnung in n Dimensionen. Die approximierenden Teilräume sind Finite‐Elemente‐Räume.
Response of a Single‐mass Vibroimpact System to White‐noise Random Excitation
Authors: Dimentberg M. F. , Menyailov A. I. 
Published: June 2007

AbstractA simple linear single‐mass oscillator with one or two rigid barriers is considered for the cases of external or parametric white‐noise random excitation. This problem is treated by using a certain piecewise‐differentiable transform of the dependent variable. For the special case of external and elastic impact the solution of the corresponding Fokker‐Planck‐Kolmogorov equation is straightforward, leading to Gaussian and truncated Gaussian stationary distributions of the velocity and displacement respectively. The general case is treated in “quasiconservative” approximation by averaging energy. This leads to a first‐oder stochastic equation for the energy and to a closed‐form solution for the stationary probability density p(E). In the case of parametric excitation necessary and sufficient conditions for the existence of p(E) are obtained.
Über ein System linearer Funktional‐Differentialgleichungen
Authors: Vogl F. 
Published: June 2007

AbstractIn der Arbeit werden Systeme linearer Funktional‐Differentialgleichungen der Form y′ (x) = Ay(λx), 0 < λ < 1, unter‐sucht. Die Elemente ajk der Matrix A sind komplexe Konstante, während die Variable x reell oder komplex sein kann. Vorerst wird die Struktur aller ganzen Lösungen angegeben. Anschließend wird für x ≠ 0 ein System spezieller analytischer Lösungen konstruiert, mit dessen Hilfe alle weiteren Lösungen dargestellt werden können. Außerdem werden die asymptotischen Eigenschaften (für x → ∞) aller Lösungen diskutiert, und es wird gezeigt, daß jeweils genau eine Lösung mit einem bestimmten, geeignet vorgegebenen asymptotischen Verhalten existiert.
Geschwindigkeits‐ und Temperaturverteilung in Hamelscher Spiralströmung
Authors: Schobeiri M. Taher 
Published: June 2007

AbstractFür die Hamelsche Spiralströmung wurde die Temperaturverteilung angegeben. Nach der Ermittlung der Geschwindigkeitsverteilung konnte die partielle Differentialgleichung der Energie mittels eines Separationsansatzes in eine gewöhnliche Differentialgleichung überführt werden. Für alle Sonderfälle dieser Differentialgleichung konnten numerische Lösungen angegeben werden.
Numerische Auswertung von Berechnungsformeln für Überschreitenswahrscheinlichkeiten stochastisch beanspruchter mechanischer Systeme
Authors: Friedrich H. , Hennig K. 
Published: June 2007

AbstractBei der Behandlung von stochastisch beanspruchten Konstruktionen hat die Berechnung der Überschreitenswahrscheinlichkeit – das ist die Wahrscheinlichkeit dafür, daß ein betrachteter stochastischer Prozeß in einem bestimmten Zeitintervall ein vorgegebenes Sicherheitsniveau mindestens einmal überschreitet – große praktische Bedeutung. Es wird auf die numerische Auswertung früher hergeleiteter Berechnungsformeln und einige Anwendungsbeispiele ein‐gegangen.
Modale und integrale Kovarianzanalyse hybrider Systeme
Authors: Wedig W. 
Published: June 2007

AbstractAm Beispiel einer vorgespannten Saite unter sowohl örtlich als auch zeitlich unkorrelierter Zufallserregung werden modale und integrale Kovarianzanalysen bei sogenannten hybriden Systemen erklärt. Diese Systeme können zwar noch selbstadjungiert sein; sie besitzen aber infolge der in den Randbedingungen enthaltenen Zeitableitungen nicht mehr die klassische Orthogonalitätseigenschaft. Es wird gezeigt, daß die geschlossen angebbaren Kovarianzlösungen der Integralanalysis mit den Reihenentwicklungen einer verallgemeinerten Modalanalysis übereinstimmen.
Analytizitätseigenschaften der Lösungen nichtlinearer Operatorgleichungen vom Hammerstein‐Typ und rekursive Bestimmung ihrer Lösung
Authors: Marx B. , Vogel J. 
Published: June 2007

AbstractIn dieser Arbeit wird für den Verzweigungsfall bei Hammersteinschen Operatorgleichungen eine Variante zur Gewinnung eines der Ausgangsgleichung äquivalenten Gleichungssystems dargelegt. Zwei Sätze über die Auflösung der zum System gehörenden Operatorgleichung werden bewiesen, die unter Analytizitätsvoraussetzungen an den nichtlinearen Operator in der Ausgangsgleichung Analytizität der Lösung bringen. Außerdem wird eine Rekursionsformel für die Koeffizienten der Lösung der lokal eindeutig auflösbaren Operatorgleichung entwickelt. Diese Rekursion wird auf die Koeffizientenfunktionen des Systems der Verzweigungsgleichungen unter Berücksichtigung der Eigenschaften des nichtlinearen Operators übertragen.
Statistische Rißausbreitung in eindimensionalen Systemen ohne Wechselwirkung
Authors: Schultrich B. , Posselt M. 
Published: June 2007

AbstractDie Bruchstatistik berücksichtigt den Einfluß der lokalen Festigkeitsschwankungen auf die Entwicklung der Vorschädigung und deren Übergang in den makroskopischen Bruch. Die hierzu gewöhnlich benutzte Einzelrißnäherung wird an einem eindimensionalen Modellsystem aus nicht miteinander wechselwirkenden Elementen getestet. Für die offene und die geschlossene Elementekette werden Mittelwert und Schwankung der Rißlängenverteilung sowie die makroskopische Bruchwahrscheinlichkeit berechnet. Die Näherungsbeziehungen lassen sich hieraus als asymptotischer Grenzfall für große Systeme gewinnen. Die Rolle der Randeffekte und der statistischen Korrelationen, in deren Vernachlässigung die Einzelrißnäherung besteht, wird genauer untersucht.
Free and Forced Vibrations of a Linear Non‐Conservative System with Multiple Eigenvalues
Authors: Kliem W. 
Published: June 2007

AbstractThe paper shows the derivation of the response of a linear system governed by the equation A\documentclass{article}\pagestyle{empty}\begin{document}$ \ddot q $\end{document} + Bq̇ + Cq = Q(t), in which the square matrices A, B and C are real and constant, but not necessary symmetric or positive definite. In addition the special case of multiple eigenvalues with an insufficient number of eigenvectors occurs. The theory is an extension of the work by Wahed and Bishop [1], which is limited to distinct eigenvalues.
Error Propagations in Implicit Discretized Viscous Flow Models
Authors: Dey S. K. 
Published: June 2007

AbstractIt has been claimed in general, that implicit finite difference solution of Navier‐Stokes' equations is unconditionally stable. A linearized stability analysis [1] showed that if finite difference representations of boundary conditions do not contain errors and if truncations errors are neglected, such a claim is justifiable. However, in most problems, boundary conditions are often approximated and hence errors originate from there. Furthermore, depending upon the flow conditions and input parameters (like time steps, mesh sizes), truncation errors may have significant contributions upon numerical solutions. In this paper these investigations have been made.
Biological vs. Chemical evaluation of toxicity and protein quality of cottonseed meals
Authors: Eagle Edward , Blalek H. F. , Davies D. L. , Bremer J. W. 
Published: June 2007

Summary
Toxicological evaluation of 68 cottonseed meals in rats failed to show a direct correlation between their toxicity and their free, total or combined gossypol content. The common practice of considering the free gossypol content of cottonseed meal as a yardstick for its toxicity is questioned.
There was poor correlation between biologically evaluated protein quality of cottonseed meals and their nitrogen solubility in 0.02N sodium hydroxide. Application of this chemical test for indicating the protein quality of cottonseed meals is likewise questioned on the basis of existing evidence.
Association of seed size with genotypic variation in the chemical constituents of soybeans
Authors: Liu KeShun , Orthoefer Frank , Brown Edward A. 
Published: June 2007

AbstractTen soybean genotypes grown in 1992 with seed size ranging from 7.6 to 30.3 g/100 seeds and maturity group V or VI were selected and tested for oil and protein content and for fatty acid composition. In these germplasm, protein varied from 39.5 to 50.2%, oil, 16.3 to 21.6%, and protein plus oil, 59.7 to 67.5%. Percentages of individual fatty acids relative to total fatty acids varied as follows: palmitic, 11.0 to 12.8; stearic, 3.2 to 4.7; oleic, 17.6 to 24.2; linoleic, 51.1 to 56.3 and linolenic, 6.9 to 10.0. Seed size showed no significant correlations with individual saturated fatty acids, protein or oil content. However, significant correlations were found between seed size and individual unsaturated fatty acids: positive with oleic, and negative with linoleic and linolenic. Oil and protein content were negatively correlated with each other. Among the major fatty acids, only the unsaturated were significantly correlated with each other: negative between oleic and linoleic or linolenic, and positive between linoleic and linolenic. A subsequent study with soybeans grown in 1993 generally confirmed these findings. Variation in relative percentages of unsaturated fatty acids andr values for most pairs of relationships were even higher than those obtained from the 1992 crop.
Lecithins in oil‐continuous emulsions. Fat crystal wetting and interfacial tension
Authors: Johansson Dorota , Bergenståhl Björn 
Published: June 2007

AbstractLecithin is a powerful emulsifier widely used in foods, feeds and pharmaceuticals. Several analytical methods have been proposed to characterize lecithins, but they are often inadequate to determine the industrial functionality. The purpose of this study was to find a relationship between the interfacial properties of lecithins (adsorption to oil/water and fat crystal/oil/water interfaces), phospholipid composition and functionality. Results show that all lecithins adsorb to fat crystals at the triglyceride oil/water interface, making their surface more polar (observed as an increase in the contact angle measured through the oil at the interface: fat crystal/oil/water). This adsorption process is quick (less than five minutes) for relatively polar lecithins, such as soybean phosphatidylcholine (PC), and results in highly polar surfaces (contact angle ∼180°). Less polar lecithins give slow adsorption (some hours) and less polar crystals (contact angle ≤90°). The adsorption of different lecithins to the oil/water interface, observed as a decrease in interfacial tension, follows the adsorption pattern to the fat crystals. We found a relation between high‐fat crystal polarity and poor lecithin functionality in margarine (margarines spatters during frying), and also between high‐fat crystal polarity and a high polar to nonpolar phospholipids [Σ(PI + PA + LPC)/ΣPE; PI, phosphatidylinositol; PA, phosphatidic acid; LPC, lysoPC, PE, phosphatidylethanolamine] ratio in lecithin. The correlations might bevia aggregation properties of lecithin in the oil. We found also that monoolein shifted the adsorption kinetics of lecithin (soybean PC) to fat crystals and the hydrophilicity of adsorbed layers probably due to formation of mixed aggregates between monoolein and soybean PC.
Isolation of erucic acid from rapeseed oil by lipase‐catalyzed hydrolysis
Authors: McNeill Gerald P. , Sonnet Philip E. 
Published: June 2007

AbstractThree lipases were compared for their ability to hydrolyze high erucic acid rapeseed oil, with the objective of concentrating the erucic acid in a single glyceride fraction. Lipase fromPseudomonas cepacia released all fatty acids rapidly and did not result in selective distribution of erucic acid.Geotrichum candidum lipase released C20 and C22 fatty acids extremely slowly, resulting in their accumulation in the di‐ and triglyceride fractions. Less than 2% of the total erucic acid was found in the free fatty acid (FFA) fraction. Lipase fromCandida rugosa released erucic acid more slowly than C20 and C18 fatty acids at 35°C but only resulted in a limited accumulation of the erucic acid in the di‐ and triglyceride fractions. However, when hydrolysis catalyzed byC. rugosa lipase was carried out below 20°C, the reaction mixture solidified and was composed solely of FFAs and diglycerides. The diglyceride fraction contained approximately 95% erucic acid while about 20% of the total erucic acid was found in the FFA fraction. It is concluded that hydrolysis at low temperature withC. rugosa lipase results in a higher purity of erucic acid in the glyceride fraction than can be obtained withG. candidum lipase, but with considerable loss of erucic acid to the FFA fraction.
Enzyme‐assisted aqueous extraction of shea fat: A rural approach
Authors: Tano‐Debrah Kwaku , Ohta Yoshiyuki 
Published: June 2007

AbstractThe use of enzyme‐assisted partial hydrolysis as a preextraction treatment in a rural shea fat extraction process to improve upon the extraction rates of the process was explored following an observed possibility in a preliminary investigation. Finely ground shea kernel meal samples were mixed with water in predetermined ratios and heated to inactivate any enzymes present. A crude protease and an enzyme with both hemicellulase and cellulase activities were added and mixed, also in predetermined concentrations. The suspensions were incubated in a waterbath shaker at temperatures ranging from 30 to 45°C for specified periods of time. The treated meal samples were then extracted using an adapted traditional aqueous extraction process. At optimum meal‐to‐water ratio of 1:2, enzyme concentration of 1%, the natural pH of the meal (about 5.3), and incubation time of 4 h, the enzyme treatment increased the extraction rate from about 40% in the typical traditional system (control) to about 75%, of the total fat content (estimated by the Soxhlet method). The enzyme‐treated meal samples were very easy to extract as there was no need to cream or whip out the fat, as is laboriously done in the traditional process. The extracted fat samples had apparently less unsaponifiable matter content and slightly less free fatty acid content and peroxide value, compared to samples from the typical traditional process and, in some cases, the Soxhlet extracted samples. The observations confirmed the results of the preliminary investigations and suggest that the enzyme‐assisted preextraction treatment could significantly improve upon the aqueous shea fat extraction process.
Viscosities and solubilities of synthetic detergent mixtures containing soluble silicates
Authors: Getty Raymond , McCready Newton 
Published: June 2007

SummarySlurries containing synthetic detergents, silicates, phosphates, and sometimes other additives, were prepared and their viscosities measured at several stresses. Portions of the mixtures were oven‐dried and dilute solutions prepared. Their turbidities and pH values were determined.Mixtures of silicate with pyrophosphate yielded lower viscosities and turbidities than with tripolyphosphate. A mixture of the two phosphates with silicate resulted in a still lower viscosity, but an intermediate turbidity. Increasing the alkalinity of the silicate decreased the turbidity, but the minimum viscosity occurred at an intermediate silicate ratio in most cases. A number of the additives tested lowered the viscosity, but all lowered the turbidity.
A bench‐scale method for evaluating the processing characteristics of oilseeds for filtration‐extraction
Authors: Graci A. V. , Spadaro J. J. , Paredes M. L. , D'Aquin E. L. , Vix H. L. E. 
Published: June 2007

SummaryA simple laboratory testing apparatus and its use have been described. With relatively few pounds of material it is possible to evaluate many preparation and filtration variables and to predict with a fair degree of accuracy the behavior of a continuous horizontal vacuum filter. It is felt that such a unit will be invaluable for use in commercial plants, especially during the start‐up operations of a new plant. The bench‐scale unit should also find application in connection with other processes employing the unit operations of extraction and filtration.
Reactions of fatty materials with oxygen. XVII. Some observations on the secondary products of autoxidation of methyl oleate
Authors: Coleman Joseph E. , Knight H. B. , Swern Daniel 
Published: June 2007

SummaryMethyl oleate, autoxidized for short and long periods of time, has been fractionated with urea. Up to a peroxide content of about 15% the autoxidation mixture can be cleanly separated into a peroxide concentrate containing 90% peroxide and unoxidized methyl oleate. From about 15% peroxide to the maximum peroxide content (35–40%) concentration to only about 70% peroxide can be obtained, and the remaining material is largely a mixture of oxygenated compounds and residual methyl oleate.If the autoxidation is conducted beyond the peak value in peroxide content, little, if any, concentration of peroxide can be obtained. Also, beyond the peak in peroxide value and in the range of 30–20% peroxide, methyl oleate is substantially absent and the autoxidation mixture consists almost entirely of oxygenated compounds containing only one functional group in the chain.Evidence is presented which shows that in the autoxidation of methyl oleate substantially all of it undergoes single attack by oxygen (or peroxides) before any significant quantity of multiple attack occurs.α,β‐Unsaturated carbonyl compounds are among the important secondary products of autoxidation.
Solubility of 1‐monostearin in various solvents
Authors: Ward T. L. , Singleton W. S. 
Published: June 2007

SummaryThe practical limits of the solubility of pure monostearin in various solvents at different temperatures has been determined for isopropyl alcohol, ethanol, acetone, methanol, and commercial hexane. The synthetic method was employed, in which the temperature of known quantities of solvent and solute was decreased until crystallization of the solute began. This temperature, corrected for supercooling and heat loss to the surrounding bath, was taken as the equilibrium temperature between the known weight of solute and the known weight of solvent.The solubility‐temperature data of monostearin in each of the various solvents are presented both graphically and in tabular form.A comparison of the solubility of monostearin in the various solvents at comparative temperatures indicates that its solubility is greatest in isopropyl alcohol and decreases in the order ethanol, acetone, methanol, and hexane.
Surfactants from fatty esters of polyalkoxylated polyol glycosides
Authors: Wilham C. A. , McGuire T. A. , Mehltretter C. L. , Otey F. H. 
Published: June 2007

AbstractThe glycoside raw materials used to prepare the surfactants were mixtures produced directly from low cost starch and the polyols by transglycosidation. After alkoxylation with ethylene oxide and propylene oxide, the glycosides were transesterified by the methyl esters of various fatty acids to yield the final products. Monolaurates of the polyalkoxylated glycosides containing a combination of 8 mol ethylene oxide and 4 mol propylene oxide per mole of glycoside showed detergency in an alkaline formulation comparable to two commercial detergents. An advantage in this application is the potential for complete biodegradation because of the fatty ester carbohydrate structures. The two monolaurates of glycerol glycoside polyethers containing 4.8 and 8 mol propylene oxide, in particular, produced oil‐inwater emulsions of high stability.
Analysis of soybean lecithin by thin layer and analytical liquid chromatography
Authors: Erdahl W. L. , Stolyhwo A. , Privett O. S. 
Published: June 2007

AbstractThe application of thin layer and analytical liquid chromatography to the analysis of two samples of commercial soybean lecithins is described. A combination of column chromatography and quantitative thin layer chromatography showed that these products consisted of ca. 82% mixture of the major phospholipids of soybeans, phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl inositol. The remainder of these products contained essentially the entire spectrum of lipid classes found in soybean oil‐some 24 known and unknown glycolipids and phospholipids, in addition to the neutral lipids. Applications of analytical liquid chromatography to these lecithins gave a composition profile of the lipid classes comparable to two‐dimensional thin layer chromatography. The potential of this method for the complete analysis of complex lipids, such as soybean lecithins, is indicated.
Biochemistry of the sphingolipides. X. Phytoglycolipide, a complex phytosphingosine‐containing lipide from plant seeds
Authors: Carter Herbert E. , Celmer Walter D. , Galanos Dimitris S. , Gigg R. H. , Lands William E. M. , Law John H. , Mueller Katherine L. , Nakayama Teishi , Tomizawa H. H. , Weber Evelyn 
Published: June 2007

SummaryA new complex lipide, phytoglycolipide, has been isolated from soybea, corn, flaxseed, peanut, sunflowerseed, cottonseed, and wheat phosphatides. This material is obtained by a mild alkaline saponification procedure which destroys glycerol‐containing lipides. The new lipide constitutes about 5% of the crude phosphatides and is obtained as a white amorphous powder of identical composition, optical activity, and solubility properties from the various sources. Phytoglycolipide gives on hydrolysis phytosphingosine (and, in the case of soybean only, an unsaturated derivative of phytosphingosine) fatty acids, inositol, glucosamine, a hexuronic acid, galactose, arabinose, mannose, and phosphate.Phytoglycolipide is the first sphingolipide of plant origin to be described and is unique among complex sphingolipides in that it has the structural features of a glycolipide and of a phosphatide.
Application of near infrared spectrophotometry to the study of the autoxidation products of fats
Authors: Slover Hal T. , Dugan L. R. 
Published: June 2007

SummaryThe usefulness and limitations of near infrared spectroscopy as applied to the oxygenated products of fat oxidation has been studied. Hydroperoxides, acids, alcohols, esters, aldehydes, and ketones all absorb in the narrow range from 2,700 mμ to 3,000 mμ. Alcohols may be distinguished from hydroperoxides and acids, but the latter are too close together to be resolved. In mixtures all the C=O absorptions attributable to esters, aldehydes, and ketones combine to form one band. In autoxidizing methyl oleate, the increase in alcohol, carbonyl, and combined acid‐hydroperoxide can be followed in the near infrared spectra of CCl4 solutions. In the absence of acid the increase in hydroperoxide absorbance is linear with peroxide value. The changes in the spectra of a reduced and bicarbonate‐washed sample of oxidized methyl oleate correlate well with the expected chemical changes.
Bureau of Commercial Fisheries Oil Research program
Authors: Stansby M. E. , Butler Charles 
Published: June 2007

SummaryThe Bureau of Commercial Fisheries has had under way since 1955 an extensive research program to develop wider uses for fish oils. The program is carried out in the Bureau's own laboratories, in university laboratories, and in other qualified laboratories.The initial effort has been concentrated largely on basic research in an effort to learn more about the chemistry of fish oils, a field heretofore incompletely explored. Some applied research projects also were begun concurrently.Basic studies are being carried out on the chemistry of the components of fish oils (for example, polyene fatty acids), on the extracted fish oils themselves, and onin situ fish oils of the fish tissue.Investigations of fish‐oil fatty acids are being made on chemical structure, methods of separation, chemical reactions, oxidative deterioration, and nutritive value, with especial emphasis on possible therapeutic aspects for human beings.The applied research projects include investigation of fish oils and the chemically modified compounds thereof as fungicides, as leather lubricants, and as ore‐flotation agents.The applied and basic programs are coordinated so that findings of the basic work can be put to use in the applied work as soon as available.