bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Note on the Analytical Resolution of a Nonhydrostatic Standing‐Wave Eigenvalue Problem for a Parabolic Basin
Authors: Lundberg P. 
Published: May 2007

AbstractThe eigenvalue problem determining the periods of slightly nonhydrostatic standing waves in a basin with parabolic bottom profile has previously been resolved using Frobenius series representations of the solutions in conjunction with boundedness conditions at the basin endpoints. Here it is shown that by subjecting the governing equation to a Benjamin‐Bona‐Mahony transformation the problem is considerably simplified and that the range of validity of a simple power series solution exceeds the one previously obtained.
On Formulations of Vorticity Systems for a Viscous Incompressible Flow with Numerical Applications
Authors: Ruas V. 
Published: May 2007

AbstractThe aim of this work is to present a series of analytical and numerical results related to vorticity formulations of the systems describing the motion of an incompressible viscous fluid. A rigorous variational framework for the two‐dimensional Stokes system is used as a basis in both the stream function‐vorticity and the velocity‐vorticity formulations. It is shown that this allows in particular a decoupled numerical solution method for the former formulation yielding optimal convergence results. On the other hand a new finite element scheme is proposed for the latter and illustrated by computer results. Finally a study on the velocity‐vorticity formulation in three dimensional space is carried out.
Direct Relations Between Curvatures of Surfaces Being in Continuous Tangency
Authors: Litvin F. L. , Hsiao C.‐L. 
Published: May 2007

AbstractThe motion of two solids provided with surfaces Σ1 and Σ2 being in continuous tangency either along a line or at a point at every instant is considered. The authors propose an approach for determining direct relations between: (i) the principal curvatures and directions of Σ1 and Σ2, (ii) the normal curvatures of Σ1 and Σ2 along two mutually perpendicular directions chosen in the tangent plane. The performed diagonalization of the curvature matrix enables to determine the directions and magnitude for the extreme relative normal curvatures of Σ1 and Σ2. The proposed approach enables: (i) to simplify substantially the determination of curvatures when one of the surfaces is represented in threeparametric form but with related parameters, (ii) to simplify the computerized simulation of contact of gear tooth surfaces, and (iii) to simplify the determination of curvatures of a surface generated by a tool with the given surface. The approach is illustrated with the example of generation of a worm (screw) by a cone surface of the tool.
Geometrisch nichtlineare Sandwichplatten unter Berücksichtigung von Schubdeformationen
Authors: Holzapfel G. A. , Wimmer H. 
Published: May 2007

AbstractBei zahlreichen flächenhaften Tragwerken mit nicht traditionellen Werkstoffen wie z. B. schubweichen Laminaten ist der Einfluß der transversalen Schubspannungen nicht mehr vernachlässigbar. Es wird eine konsistente geometrisch nichtlineare Schubverzerrungstheorie erster Approximation für Platten, die aus p Schichten aufgebaut sind, vorgestellt. Die Stoffgleichungen werden mit einem geeigneten Schubkorrekturfaktor abgeleitet. Die Anwendung der Theorie und der Einfluß der Schubdeformationen auf die Verschiebungsgrößen und die realen Schnittgrößen werden an Hand einer dicken Sandwichplatte mit unterschiedlichen Randbedingungen veranschaulicht.
On the Onset of Chaotic Dynamics in Asymmetric Oscillators
Authors: Bruhn B. , Koch B.‐P. , Schmidt G. 
Published: May 2007

AbstractDas Einsetzen chaotischen Dynamik in einem fremderregten und gedämpften nichtlinearen Oszillator wird mit Hilfe der Melnikovmethode studiert. Besondere Aufmerksamkeit erhält der Einfluß eines Asymmetrieparameters in der Bewegungsgleichung. In Gegensatz zum symmetrischen Fall hat die Verzweigungsfunktion Singularitäten auf einer diskreten Menge von Frequenzen. Die Methode der harmonischen Balance begründet qualitativ einige der Ergebnisse der Melnikovmethode. Für ausgewählte Parameterwerte werden die analytischen Voraussagen durch numerische Rechnungen bestätigt.
The Inclusion of Dirichlet Eigenvalues with Singularity Functions
Authors: Ennenbach R. , Niemeyer H. 
Published: May 2007

AbstractWe are concerned with the Dirichlet eigenvalue problem Δu + λu = 0 G, u = 0 on Γ, where G is a bounded, two dimensional domain with sufficiently smooth boundary Γ. We deal with the “Ansatz” \documentclass{article}\pagestyle{empty}\begin{document}$ u\left({x,\lambda } \right) = \sum\limits_{m = 1}^M {a_m Y_0 } \left({\sqrt \lambda |x - y_m |} \right) $\end{document} to compute approximate eigenpairs (u*, λ*) by the collocation method. Lower and upper eigenvalue bounds are estimated by an inclusion theorem due to Kuttler‐Sigillito. In contrast to usual choices of trial functions, it is possible to control the numerical stability by placing the source points in dependence of M. The effect arises from the logarithmic singularity for x = ym and allows us to sharpen the eigenvalue bounds by increasing M. We give a strategy for placing the sources, present various application and give a comparison of results which indicates a high efficiency of the method.
Turbulent Flow Calculations by the Nonlinear Multi‐Grid Method
Authors: Nowak Z. P. , Salcudean M. 
Published: May 2007

AbstractThe Nonlinear Multi‐Grid Method (NMGM, HACKBUSCH [2], [3]) is a relatively unexplored alternative to the Full Approximation Storage method (FAS, BRANDT [1]). Excellent convergence of the NMGM was reported in [3] for a non‐linear Poisson problem in a square. In the present paper, the NMGM is applied to a steady‐state three‐dimensional turbulent flow problem. The problem arose from the study of a row of jets supplying the air into the chamber of an industrial furnace. The description of the NMGM is given in [2]. Here, we present the flow problem in its analytical and discrete form, describe our choices for the various elements of the NMGM, and demonstrate a very good performance of the method in a series of convergence tests. The locally coupled method (VANKA [13], ROLLET et al. [11]) is used for smoothing the residuals of the continuity and momentum equations. The best performance is obtained when a simplified form of the pressure correction method (PATANKAR and SPALDING [9] is additionally applied to enforce the given mass flows through the flowfield sections.
Efficient Numerical Integration of the Equations of Motion of Non‐Smooth Mechanical Systems
Authors: Meijaard J. P. 
Published: May 2007

AbstractA method for dealing with the numerical integration of non‐smooth mechanical dynamical systems is presented. This method is based on the integration of piecewise smooth parts and piecing these parts together with appropriate transition conditions. A distinguishing characteristic of this method is that it can deal with very close transitions. The method is applied to a forced friction oscillator with one degree of freedom, and a system of two coupled non‐linear oscillators in which one oscillator has an amplitude‐limiting stop.
Complete General Solution of the Brinkman Equations
Authors: Sekhar G. P. Raja , Padmavathi B. S. , Amaranath T. 
Published: May 2007

AbstractIn this note, we introduce a new representation of the complete general solution of the Brinkman [1] equations. We also show that the representation for the velocity and pressure given by Padmavathi et al. [2] is a complete general solution of the Brinkman [1] equations.
Solitary Waves in a Prestressed Thick Elastic Tube Containing an Inviscid Fluid
Authors: Demiray H. 
Published: May 2007

AbstractIn the present work, employing the nonlinear equations of an incompressible, isotropic, and elastic body and the exact equations of an incompressible inviscid fluid, the propagation of weakly nonlinear waves in an elastic thick tube filled with an inviscid fluid is studied. The tube is initially assumed to be subjected to a large inner pressure P0 and the axial stretch λz, and, in the course of blood flow a large time dependent radial displacement is superimposed on this static field. The nonlinear equation governing the radial motion of the tube is obtained. Utilizing a reductive perturbation technique, the propagation of weakly nonlinear waves is studied and the KdV equation is obtained as the evolution equation. Due to the dependence of the coefficients of the nonlinear evolution equation on initial deformation and the geometrical characteristics it is shown that the solution profile changes with initial deformation and the thickness ratio.
Fractionation of castor oil methyl esters by liquid‐liquid extraction
Authors: Lakshmanan C. M. , Laddha G. S. 
Published: May 2007

ConclusionThe phase equilibrium data are presented for methyl esters‐furfural‐hexane and methyl esters‐nitromethane‐hexane at 30°C.The hydroxyl values of ester samples obtained from the furfural and nitromethane phases indicate that furfural and nitromethane can be used as solvents for fractionating hydroxy esters from the mixed esters obtained by the methanolysis of castor oil.
Synthesis of polyoxyethylene derivatives of diesters of sucrose with long‐chain fatty acids
Authors: Komori Saburo , Okahara Mitsuo , Okamoto Kenzo 
Published: May 2007

SummarySince the long‐chain fatty acid sucrose diesters inevitably produced in the synthesis of monoesters are only slightly soluble in water, no important use can be found for them at the present time except as oilsoluble emulsifying agents.In order to exploit new uses we have attempted to improve their solubility in water by introducing oxyethylene radicals into the molecule.The addition reaction of ethylene oxide with the sucrose diesters was carried out in an autoclave in the presence of alkaline catalysts. With the reaction temperature maintained between 100–130° the pressure decreased as the reaction proceeded, and one to two hours were required to consume the ethylene oxide used.The addition products are yellow or orange oily materials soluble in water. Aqueous solutions showed good surface‐active properties.
Hydrogenation of fatty oils with palladium catalysts. V. Products of the tall oil industry
Authors: Zajcew Mykola 
Published: May 2007

AbstractConditions were found for reducing tall oil distillate to an iodine number of 22 with a sufficiently small amount of palladium catalyst to make the process commereially feasible. The operating conditions were 200°C and 2,600 psi.Tall oil fatty acids were reduced with palladium and the concentration of linoleic acid,cis‐oleic acid, saturated acid, andtrans isomers were determined as a function of iodine number. The five‐platinum group metals (Pt, Pd, Ir, Rh, Ru) were compared as to activity, selectivity of partial hydrogenation, and tendeney to formtrans‐isomers.
Effect of free carboxylic groups on the course of sulfur trioxide sulfonation of unsaturated fatty acids
Authors: Sauls Thomas W. , Rueggeberg Walter H. C. 
Published: May 2007

SummaryThe direct action of one mole of sulfur trioxide in liquid sulfur dioxide at atmospheric pressure at −10 to −9°C. on one mole of unsaturated fatty acids such as oleic acid, undecylenic acid, and crotonic acid yielded 85–90% of sulfonated products in which a monosulfonated derivative, rich in residual carbon to carbon unsaturation, predominates. Hydroxy sulfonates and sulfonated‐sulfated products, postulated to form from carbyl sulfate intermediates, are present in lesser amounts.Esters of unsaturated fatty acids, such as n‐propyl oleate, require at least two moles of sulfur trioxide for 80–90% yields of sulfonated product. These sulfonated products are postulated to form almost exclusively through the carbyl sulfate intermediate.The free carboxyl group apparently determines the course of sulfonation. Its action is believed to be that of first forming an acyl sulfate or mixed anhydride with sulfur trioxide, followed by hydrogen replacement in a methylene group, probably in an allyl position to the double bond, with a sulfonic acid group. The mechanism and nature of products resemble those previously observed by Suter in the dioxane‐sulfur trioxide sulfonation of methallyl chloride (6).The sulfonated unsaturated reaction products from oleic and undecylenic acids exhibit lower double bond reactivity toward hydrogen and halogen addition than the unsulfonated starting materials.The monosulfonated oleic acid, because of its stability toward hydrolysis, holds promise as an important surface‐active agent, particularly under acidic conditions.
Structural studies on sucrose monolaurate
Authors: York William C. , Finchler Arthur , Osipow Lloyd , SNell Foster Dee 
Published: May 2007

ConclusionA product corresponding to sucrose monolaurate was prepared by the alcoholysis of methyl laurate with sucrose. This product appears to be a mixture, with the principal component having the lauroyl radical at the 6‐position of the glucose portion.
Reactions of unsaturated fatty alcohols. VII. Polymerization of vinyl ethers catalyzed by stannic and ferric chlorides
Authors: Dufek E. J. , Awl R. A. , Gast L. E. , Cowan J. C. , Teeter H. M. 
Published: May 2007

SummaryVariables affecting the use of stannic chloride as a catalyst for initiating polymerization of conjugated and nonconjugated soybean vinyl ether were studied. Molecular weight of the polymers increased with an increase in catalyst and a decrease in initiation temperature, and it decreased when the amount of moisture in the solvent, the amount of free fatty alcohol in the monomer, or the ratio of solvent to monomer was increased. Aromatic and aliphatic hydrocarbon solvents were superior to halogenated solvents for conducting polymerizations. Similar results were obtained with nonconjugated monomers except that viscosities of the polymers were considerably lower than those of polymers of the same molecular weight obtained from conjugated monomer.To obtain polymers suitable for film‐forming studies (4,000–6,000 molecular weight) polymerization is initiated preferably at 25°C. with 3 ml. of anhydrous toluene used per gram of monomer and 4.8 mmoles of stannic chloride per mole of monomer. Monomer purity should be at least 98%.Ferric chloride hexahydrate initiated polymerization at 25°, but polymerization was incomplete, and the polymers had relatively low molecular weights.
The preparation of polyunsaturated aliphatic aldehydesvia the acyloin condensation
Authors: Gauglitz Erich J. , Malins Donald C. 
Published: May 2007

SummaryThe preparation of linolenaldehyde and of mixed aldehydes from highly unsaturated sources, such as menhaden oilvia the acyloin condensation, is described. Reduction of the acyloins and subsequent cleavage of the glycols gave over‐all yields of 85 to 90% free aldehydes.The intermediates in the synthesis as well as the final products were analyzed in part by the novel method of thin‐layer silicic acid chromatography.
A report on the problem of residual solvent in solvent‐extracted meals
Authors: Gastrock E. A. , Spadaro J. J. , Crovetto A. J. , Brian Ross 
Published: May 2007

SummaryThe hazards of excess residual solvent in solventextracted meals and methods currently used for its measurement are discussed. Preliminary results are reported with a simple copper‐cup flash‐tester with concentric rings as heating surfaces. Solvent contents as low as 0.03% can be detected. The method is semiquantitative. The method may be useful for plant control purposes.
Industrial fat splitting
Authors: Lascaray Lucio 
Published: May 2007

SummaryThe reaction of fat splitting, whatever the process employed, obeys the following general rules:

The greater the proportion of free fatty acids in the fat to be hydrolyzed, the shorter will be the induction period.

The higher the reaction temperature and the more advanced the process, the less necessary the stirring.

The rate of hydrolysis is augmented by the raising of temperature and by the use of catalysts, proportionally to its quantity. The most active catalysts are those which most increase the solubility of water in the oil phase and which at the same time most activate that water, raising its degree of dissociation.

The degree of hydrolysis at equilibrium, whatever the fat to be split, depends exclusively on the glycerol concentration of the sweet waters.
Volatile cleavage products of autoxidized soybean oil
Authors: Kawahara F. K. , Dutton H. J. 
Published: May 2007

SummaryVolatile odor principles of reverted soybean oil collected at very low temperature have been fractionated into rancidity and reversion components by adsorption on silica gel. These principles apparently contain aldehyde groups since they can no longer be detected organoleptically after the addition of aldehyde reagents.Isolations of individual aldehydes within the rancid and reverted fractions were made by forming the 2,4‐dinitrophenylhydrazones and chromatographically separating these colored derivatives. Identifications were based upon melting points, ultimate analyses, and adsorption data.The following aldehydes were identified: acetaldehyde, propionaldehyde, α‐pentenal, and hexanal. There is strong evidence that crotonaldehyde is also present although not completely resolved from propionaldehyde as dinitrophenylhydrazones.
Phase relations in the solvent winterization of molecularly rearranged peanut oil and cottonseed oil
Authors: Boucher Richard E. , Skau Evald L. 
Published: May 2007

SummarySystematic phase‐relation data have been obtained to determine the effect of either mild or extensive molecular rearrangement on the winterization behavior of peanut or cottonseed oils. The results show that the introduction of the molecular rearrangement step before solvent winterization is disadvantageous. A larger percentage of solid must be removed to obtain a winterized oil, especially for cottonseed oil, and lower yields result. Lower chilling temperatures and longer chilling periods are also required, partially because of a lower rate of crystallization. In addition the settling qualities of the solid separating are markedly impaired.
Measurement of foam consistency
Authors: Scott G. V. , Thompson W. E. 
Published: May 2007

SummaryFoams from detergent solutions may show large differences in apparent viscosity or consistency. Procedures are given for relative measurement of this property.A decrease in foam consistency may be obtained with soap solutions upon addition of inorganic salt or of hardness. A critical temperature range exists for consistency of foams from detergent systems. Foams of high consistency may be altered to low consistency by raising the temperature.The data suggests a relation between foam consistency and the liquid drainage and surface viscosity characteristics of foam systems. High consistency values were obtained for foams having slow drainage rates and high surface viscosity. These characteristics for foams of detergent solutions are attributed to the presence of certain polar organic substances (e.g., saturated fatty alcohols and acids) which are strongly adsorded at the liquid‐air interfaces.
A method for the quantitative determination of relative wear of soap bars
Authors: Masters E. B. 
Published: May 2007

SummaryA method for the quantitative determination of the relative wear of soap bars has been developed. The method is fairly simple and rapid, requiring about an hour of labor and from 8 to 12 hours of aging of samples during the test. The method is based upon the measurement of thickness of samples before and after subjecting them to wear by a sponge and warm water. Application of the method to samples of different thicknesses and surface areas shows good reproducibility, and the method is believed to be applicable in studies which require high sensitivity.
The determination of moisture in tung fruit
Authors: Holmes Raiford L. , Minor Jacob C. , McKinney R. S. 
Published: May 2007

Summary and ConclusionsSix methods for determining moisture in tung fruit and seeds were compared.The highest moisture values, and probably those most reliable, were obtained by drying the ground tung fruit in the vaccuum oven at 101°C. for 2.5 hours under 12‐mm. pressure, and by the Karl Fischer titration method. In using the Karl Fischer method on tung products, the sample must be digested in methanol at 60°C. Of these two methods the vacuum oven method is simpler and generally preferable.Somewhat lower moisture values were obtained by the forced draft oven and toluene‐distillation methods. The results obtained in the forced draft oven method were low because of oxidation of the oil in the samples. One hour at 101°C. in the forced draft oven seems to be the optimum time for moisture determination, and no appreciable error in the oil content results from using the percentages of moisture so determined to calculate the oil content to basis of sample as received.For routine analysis, heating the ground tung fruit sample in a hot air blower for 15 minutes at 126.7°C. (260°F.) and adding a correction of 1.35% to the percentage of moisture obtained gives sufficiently accurate values for factory control purposes.The radio frequency meter gave values close to those obtained in the vaccum oven method against which it was standardized. It was necessary to standardize the meter separately for fruit, seeds, and kernels. In practice many samples of wet fruit would be encountered which would exceed the range of the particular instrument used.
Internal hydrogen bonding, rotational isomerism and differentiation of 1,2‐ and 1,3‐diglycerides by near infrared spectroscopy
Authors: Susi H. , Morris S. G. , Zell Tatiana E. , Scott W. E. 
Published: May 2007

AbstractThe OH stretching modes of 1,2‐ and 1,3‐diglycerides in dilute carbon tetrachloride solution have been investigated in the fundamental and first overtone region with a spectral resolution of about 1 cm蜢1. The spectra of both position isomers can be interpreted in terms of three predominant configurations: one internally H‐bonded and two involving no H‐bonds. The fraction of H‐bonded molecules appears to be relatively low. The data suggest that the H‐bonded form of 1,3‐diglycerides has atrans, gauche configuration around the glyceride CC bonds, while the non‐H‐bonded forms probably have atrans, trans configuration around the glyceride backbone, OH being eithertrans orgauche with respect to the nearest C‐H group. In 1,2‐diglycerides H‐bonds seem to be predominantly formed between groups attached to the ॅ, े carbons of the glyceride residue, the configuration around the backbone beingtrans, trans; two stretching band of non‐H‐bonded OH groups are associated with rotational isomerism around the alcoholic CO bond. The usefulness of OH stretching modes for analyzing mixtures of 1,2‐ and 1,3‐diglycerides is discussed.
The acetylenic acid inComandra pallida andOsyris alba seed oils
Authors: Mikolajczak K. L. , Earle F. R. , Wolff I. A. 
Published: May 2007

AbstractGas‐liquid chromatographic (GLC) analyses are reported for fatty acid methyl esters from seed oils of two previously unreported species of Santalaceae,Comandra pallida A. DC. andOsyris alba L. The major component in each (43 and 57%, respectively) is an enynoic acid, probablytrans‐11‐octadecen‐9‐ynoic (ximenynic) acid which has been found in seed oils of other members of this family. Equivalent chain lengths by GLC analysis and infrared and ultraviolet spectra agree with those obtained by our analyses ofXimenia americana L., in which ximenynic acid is known to occur. The spectral data also agree with those in literature reports on ximenynic acid. The positions of unsaturation have, however, not been rigorously established for the two species newly reported.