bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Exact Analysis of Unsteady Convective Diffusion in an Annular Pipe
Authors: Ramachandra Rao A. , Deshikachar K. S. 
Published: May 2007

AbstractAn exact solution to the unsteady convective diffusion equation for the dispersion of a solute in a fully developed laminar flow in an annular pipe is obtained. Generalized dispersion model which is valid for all time after the injection of solute in the flow is used to evaluate the dispersion coefficients as functions of time. It is observed that the axial dispersion decreases with an increase in the radius of the inner cylinder.
Verallgemeinerte Inversen ganzzahliger Matrizen
Authors: Springer J. 
Published: May 2007

AbstractEs werden die speziellen Eigenschaften der Moore‐Penrose‐Inversen A+ beliebiger ganzzahliger Matrizen A untersucht. Verschiedene Formeln für einen gemeinsamen ganzzahligen Nenner der (rationalen) Elemente von A+ werden vorgestellt und untereinander verglichen. Unter der Voraussetzung, daß die Elemente von A betragsmäßig beschränkt sind, wird eine obere Schranke für die Konditionszahl ||A||·||A+|| angegeben.
Mixed Problems of Potential Theory in Spherical Coordinates
Authors: Fabrikant V. I. 
Published: May 2007

AbstractExact solution in closed form is obtained to the following mixed problem for a charged sphere: an arbitrary charge density distribution is prescribed at the surface of a spherical cap while an arbitrary potential is given at the rest of the sphere. A new method is introduced making the procedure straightforward and elementary, no special functions or integral transforms involved. Some further applications of the method are discussed. A new type of solution is obtained for the Dirichlet problem with discontinuous boundary conditions. Several examples are considered.
Vibration of a Visco‐Elastic Spherical Immiscible Liquid System
Authors: Bauer H. F. , Eidel W. 
Published: May 2007

AbstractThe vibrational behavior of spherical visco‐elastic systems in a zero‐gravity environment has been treated, including axi‐and asymmetric oscillation modes. The systems treated are the liquid drop, two immiscible liquids in a spherical container and an annular spherical liquid layer around a rigid center sphere. The frequency equations were obtained and found to be independent of the angular mode, exhibiting a multiplicity of eigenfrequencies. In addition the free surface‐or interface displacement as well as the velocity distributions in radial‐, angular‐ and meridional direction were analytically determined. For the liquid drop those have also been evaluated numerically, while for the remaining systems only the frequency equation for the damped natural frequencies have been determined numerically.
Electrically Driven Flows in MHD with Mixed Electromagnetic Boundary Conditions
Authors: Sezgin M. , Aggarwala B. D. , Ariel P. D. 
Published: May 2007

AbstractFlow of viscous, incompressible, electrically conducting fluid, driven by imposed electric currents has been investigated in the presence of a transverse magnetic field. The boundary perpendicular to the magnetic field is perfectly conducting partly along its length. Three cases have been considered: a) flow in the upper half plane when the boundary to the right of origin is insulating and that to the left is perfectly conducting, b) flow in the upper half plane when a finite length of the boundary is perfectly conducting, and c) flow in a flat channel when a finite length of boundary in each plane, symmetrically situated, is perfectly conducting. In case a), an exact analytical solution is derived, from which the existence of a boundary layer, parabolic in shape and emanating from the point of discontinuity in electrical boundary conditions, is established. In cases b) and c), the problem is reduced analytically to a Fredholm's integral equation of second kind, which is solved numerically. A number of transformations and valid approximations are used to simplify the task of numerical computation. Velocity contours and current lines have been plotted for each problem. For large values of Hartmann number the parabolic boundary layer mentioned above is demarcated.
Biorthogonale Entwicklungen von Verteilungsdichten und ihre Anwendung zur Analyse stochastischer Systeme. Teil I: Mathematische Grundlagen
Authors: Ahlbehrendt N. , Sperling L. 
Published: May 2007

AbstractDie in [4, 5, 6] auf der Grundlage der Gram‐Charlier‐Reihe entwickelte Methode der verallgemeinerten Quasimomenten‐funktionen (hier QME(pG) genannt) wurde in [7] unter Zulassung nichtgaußscher analytischer nullter Näherungen p0(z) der Wahrscheinlichkeitsdichte p(z) zu einem Verfahren QME(p0/Ψ) verallgemeinert. Im vorliegenden ersten Teil wird eine weitere Verallgemeinerung QME(p0/F) vorgenommen, die diese Reihen als Spezialfälle enthält und die auch nichtanalytische p0(z) sowie Prozesse mit eingeschränktem Definitionsbereich zuläßt. Darüber hinaus wird für eindimensionale Verteilungs‐dichten ein praktikables Auswahlkriterium für p0(z) vorgeschlagen. Die im ersten Teil enthaltenen Empfehlungen zur Anwendung der auf biorthogonalen Funktionssystemen basierenden Reihe QME(p0/F) für Analysezwecke werden im Teil II durch eine Reihe von Beispielen belegt.
Lack of mutagenicity of products formed by ammoniation of gossypol
Authors: Lee L. S. , Ehrlich K. C. , Daigle K. W. , Koltun S. P. 
Published: May 2007

AbstractGossypol distributed on an inert gel carrier was treated in a pressurized ammoniation chamber used to detoxify aflatoxin‐contaminated cottonseed meal. Ames tests for mutagenicity were performed on untreated gossypol and on fractions eluted sequentially from the gel. Nonammoniated gossypol was not mutagenic nor were any of the products formed from gossypol by ammoniation.
Crystallization and transformation mechanisms of α, β‐ and γ‐polymorphs of ultra‐pure oleic acid
Authors: Suzuki M. , Ogaki T. , Sato K. 
Published: May 2007

AbstractCrystallization and transformation mechanisms of ultrapure (99.999%) oleic acid were examined by Differential Scanning Calorimetry (DSC) and X‐ray diffraction. X‐ray diffraction spectra revealed three different polymorphs newly named α, β and γ, which differ from each other most significantly in the short spacing spectra. α and β were found to be equivalent to the previous data which Lutton named low and high melting polymorphs, whereas γ was newly identified in the present study. DSC studies have clarified the thermodynamic stability of the three polymorphs in a range of temperature from ‐20 to 16.2 C. β is always most stable, whereas α and γ are metastable, undergoing a reversible first‐order solid‐state transformation at ‐2.2 C (on heating). DSC also showed that the crystallization behaviors are strongly dependent on the polymorphs; α crystallizes at a much higher rate than β; despite the fact that they have close melting points (α, 13.3 C; β, 16.2 C). It was demonstrated for the first time that the above peculiar polymorphic behaviors of oleic acid are quite different from those of stearic acid, a saturated fatty acid with the same carbon chain length.
Triglyceride composition of tobacco seed oil
Authors: Sengupta A. , Mazumder U. K. 
Published: May 2007

AbstractFatty acid and triglyceride compositions of Indian tobacco seed oil (Nicotiana rustica) have been determined by combination of the techniques of systematic crystallization at low temperatures, pancreatic lipase hydrolysis, and gas liquid chromatography of methyl esters. The percentages of individual fatty acids were found to be linoleic 71.2, oleic 15.7, palmitic 8.4, and stearic 3.8. The special characteristic of the tobacco seed oil is its content of 37.4, 22.8, 4.9, 19.7, 9.3, and 3.3% of trilinolein, dilinoleoolein, dioleolinolein, dilinoleosaturated, linoleooleosaturated, and linoleodisaturated glycerides, respectively. In the present investigation, preference of linoleic acid over oleic acid for the 2‐position of glycerol moiety was not observed.
Modification of jojoba oil for lubricant formulations
Authors: Bhatia V. K. , Chaudhry Alka , Sivasankaran G. A. , Bisht R. P. S. , Kashyap Meenu 
Published: May 2007

AbstractJojoba oil has good lubricity and it can be utilized as a component in lubricating oil formulations. The physicochemical properties of the oil when compared with those of mineral oil base stocks showed that the pour point, acid value and oxidative stability were the limiting factors in its use as a base stock. Studies were carried out to improve these properties. The results indicated that these properties can be modified by physical and chemical methods and also by additive viscosity of jojoba oil by partial sulfurization, resulting in widening the scope of its utilization in developing lubricant formulations.
Solvent extraction of the oils of rubber, melon, pumpkin and oilbean seeds
Authors: Attah J. C. , Ibemesi J. A. 
Published: May 2007

AbstractSolvents of differing dielectric constant were used to extract oils from the seeds of: rubber [Hevea brasiliensis (Kunth) Muell. Arg.], melon [Colocynthis vulgaris Schrad], fluted pumpkin [Telfairia occidentalis Hook f.] and oilbean [Pentaclethra macrophylla Benth]. The aim was to examine the effect of solvent polarity on oil yield and oil properties.The oils were extracted under Soxhlet conditions with the following solvents: petroleum benzene (60–80°C), cyclohexane, isopropyl ether, ethyl acetate, tetrahydrofuran, propan‐2‐ol and acetone. The oils were characterized by acid number, iodine value and color intensity determinations.The oil yields of each seed in different solvents ranged as follows: 58.0–64.4% (pumpkin), 56.1–59.1% (melon), 40.6–48.8% (rubber) and 35.4–43.3% (oilbean). The equilibrium extracting capacity of each solvent was found to depend on two factors, namely, the nature of the oil and the polarity of the solvent. Both factors were found to determine the acid number, iodine value and color intensity of each oil.
An investigation of rice bran oil tank settling
Authors: Belavadi V. K. , Bhowmick D. N. 
Published: May 2007

AbstractA wax‐like settling is observed in tanks in which rice bran oil is stored. “Soft” and “hard” wax fractions have been isolated from this settling by solvent Crystallization. Previous investigation has shown that the settling consists mainly of wax esters of long chain alcohols and long chain fatty acids. The present work describes the column chromatographic analysis of unhydrolyzed tank settling. The presence of an aromatic moiety is indicated in the infra red spectrum. Comparison of data obtained by analysis of the tank settling before and after hydrolysis shows that it contains only 33% of monomeric esters; the remainder may be present as a polymeric ester, as found in carnauba wax. Investigation of different samples of rice bran oil has shown that the ratio of monomeric to polymeric fraction varies with the history of the bran.
The effect of surfactant structure on the rate of oil solubilization into aqueous surfactant solutions
Authors: Bolsman T. A. B. M. , Veltmaat F. T. G. , van Os N. M. 
Published: May 2007

AbstractReduced washing temperatures decrease the rate of the various processes in a laundry cleaning cycle. This implies that fast acting detergents are needed if acceptable washing performance is to be maintained within a realistic period of time. An important factor is the rate of oily soil removal which, among other things, is a function of the molecular structure of the surfactants used in the detergent. To support the selection of proper surfactants we have established relationships between chemical structure and rate of oil solubilization for a series of alkylarenesulfonates with various alkyl chain lengths, points of attachment of the phenyl group at the alkyl chain, and aromatic substitution patterns. It is shown that oil solubilization kinetics are very sensitive to the geometry of the surfactant structure: for a set of isomeric alkylarenesulfonates the rate of oil solubilization can be made to by more than an order of magnitude by changing the substitution pattern around the aromatic ring. The results offer a predictive tool for the design of molecules with the proper surface activity under a wide set of experimental conditions.
Gas liquid chromatography analysis of the fatty acid composition of fats and oils: A total system for high accuracy
Authors: Craske John D. , Bannon Cecil D. 
Published: May 2007

AbstractThe generally accepted approach to the analysis of fatty acid methyl esters (FAME) by gas liquid chromatography (GLC) is to analyze a standard mixture of known composition and to determine empirical correction factors for individual FAME. These correction factors, which are a composite of the theoretical flame ionization detector (FID) relative response factors and an empirical factor to correct for any system errors that may be present, then are used to correct the raw peak areas of the individual FAME of the sample undergoing analysis. It is proposed that this approach is fundamentally unsound as a means of generating consistently accurate results. Rather, it has been proven that theoretically calculated FID relative response factors are valid, both for the saturated and unsaturated FAME commonly encountered in edible oils, and that these should be used as the only response factors for the correction of raw peak areas. Thus, the proper approach to the generation of highly accurate results is to optimize both equipment and operator technique so that a correct answer is obtained for a primary standard when these theoretical factors are used, rather than to introduce an empirical correction factor other than the theoretical response factor to take account of faulty practice. Eight facets of equipment operation or operator technique have been identified which must be addressed to optimize accuracy.
Dietary factors and aflatoxin toxicity: I. comparison of the effect of two diets supplemented with aflatoxin B1 upon two different strains of rats
Authors: Alfin‐Slater R. B. , Aftergood L. , Wells P. , Melnick D. , Straus R. 
Published: May 2007

AbstractPrevious studies in this laboratory with rats fed low levels of aflatoxin as a component of peanut discards, suggested either a strain tolerance for aflatoxin or a possible protective factor present in the diets used. In this study, two strains of rats, the Charles‐River strain and the former USC strain, were used to test the effect of 1.7 ppm purified aflatoxin B1 included for 3 months in two different diets; one previously used in this laboratory and one used by other investigators in aflatoxin studies. After an experimental period of either 12 or 18 months, growth, mortality, gross pathology, and organ wt were measured, and histopathological examination and biochemical analyses were performed. Plasma and liver cholesterol levels, total liver lipids, and fatty acids in the various lipid fractions of plasma, liver, and liver tumor lipids were measured. Both strains of rats proved to be susceptible to aflatoxin toxicity at this level as manifested by the appearance of hepatomas; however, liver involvement was more extensive in the Charles‐River rats. The diet used by other investigators produced symptoms similar to those observed as a result of essential fatty acid deficiency and also affected the response to aflatoxin through an aggravation of symptoms, i.e. an inhibition of growth and increased size and severity of the liver tumors.
Stationary catalysts for the continuous hydrogenation of fats
Authors: Mukherjee K. D. , Kiewitt Irmgard , Kiewitt M. 
Published: May 2007

AbstractHydrogenation characteristics of a wide variety of stationary catalysts were studied with an aim to explore their possible use in the continuous hydrogenation of fats. Refined soybean oil was hydrogenated continuously in a vertical flow‐through reactor over a fixed bed of catalyst. Catalysts investigated were pelleted products containing Raney nickel, reduced nickel, reduced palladium, and copper chromite, as well as granulated alloys of the Raney type, such as Ni‐Al, Cu‐Al, Pd‐Al, and Cu‐Cr‐Al, which were activated with alkali. These catalysts offered a wide choice of activity, selectivity, and ability to form geometrical isomers. Pelleted copper chromite and granular Raney copper‐chromium were found to be highly selective toward the linolenate moiety of soybean oil, whereas pelleted palladium on carrier, as well as granular Raney nickel, Raney copper, and Raney palladium, though moderately selective, exhibited very high activity even at relatively low temperatures. A unique feature of most of the stationary catalysts was the remarkably high rate of hydrogenation. With most catalysts, the iodine value of soybean oil was reduced by 40–60 units within a reaction period of 2–4 min. The hydrogenated fat was practically free of catalyst particles.
Alcoholic extraction of vegetable oils. Part IV. Solubilities of vegetable oils in aqueous 2‐propanol
Authors: Kanth Rao Rama , Arnold Lionel K. 
Published: May 2007

SummarySolubilities of 14 vegetable oils in four different concentrations of aqueous 2‐propanol at various temperatures were determined by a direct and simple method. Comprehensive solubility data of these oils and the critical solution temperatureversus 2‐propanol composition data are presented in tabular form. Solubility of each oil in aqueous 2‐propanol increases with temperature until the critical solution temperature is reached, at and above which oil and the solvent are miscible in all proportions. Further the critical solution temperatures of all the oils with aqueous 2‐propanol solutions increased with the increase in water content of 2‐propanol solutions. There appears to be a general relation between fatty acid contents of the oils and critical solution temperatures which needs further study.
Fatty acids of asparagus seed oil
Authors: Hopkins C. Y. , Chisholm Mary J. 
Published: May 2007

SummaryAsparagus seed, Mary Washington variety, was found to contain 14.7% of glyceride oil having iodine value 135.1, saponification value 185.5, and unsaponifiable matter 1.46%. The oil was converted to methyl esters, and the mixed esters were separated by fractional distillation and low‐temperature crystallization. The acids were identified by chemical and physical methods. The % composition of the fatty acids is estimated from the data as follows: palmitic 3, linoleic 57, oleic 27, stearic 2, eicosenoic 1.5, arachidic 0.6, undetermined 9. The oil is somewhat similar to corn oil in composition. It has at least 2% of acids of the C20 series, which have not been reported previously in this plant family (Liliaceae).
Epoxidation of polyesters of tetrahydrophthalic acid and unsaturated alkyd resins
Authors: Pearce John W. , Kawa John 
Published: May 2007

SummaryNew polyepoxides are reported which are epoxidation products of unsaturated polyesters. These polyepoxides are unique in that they may be formulated to have a large number of epoxide groups per molecule; 10 or more may be practically obtained.Anin situ process for the formation of peracetic acid, using dehydrated cation exchange resin of the styrene‐divinyl benzene sulfonic acid type, has been described for the efficient epoxisation of the unsaturated polyesters reported.A dehydrated strong base anion exchange resin will remove free acid, the major impurity resulting from the peracid epoxidation reaction, without contaminating the polyepoxide polyester with appreciable water and without appreciable loss in epoxide content during the purification. Alternatively co‐distillation of the free acid with aromatic solventin vacuo may be used as a method of purification but with some loss in epoxide content. These techniques are desirable in preparations of compositions of the type described wherein the usual washing techniques cannot be employed.
Monitoring the oxidation of edible oils by Fourier transform infrared spectroscopy
Authors: van de Voort F. R. , Ismail A. A. , Sedman J. , Emo G. 
Published: May 2007

AbstractEdible fats and oils in their neat form are ideal candidates for Fourier transform infrared (FTIR) analysis, in either the attenuated total reflectance or the transmission mode. FTIR spectroscopy provides a simple and rapid means of following complex changes that take place as lipids oxidize. Safflower and cottonseed oils were oxidized under various conditions, and their spectral changes were recorded and interpreted. The critical absorption bands associated with common oxidation end products were identified by relating them to those of spectroscopically representative reference compounds. The power and utilty of FTIR spectroscopy to follow oxidative changes was demonstrated through the use of “real‐time oxidation plots.” A quantitative approach is proposed in which standards are used that are spectroscopically representative of oxidative end products and by which the oxidative state of an oil can be defined in terms of percent hydroperoxides, percent alcohols and total carbonyl content. By using either relative absorption as a basis or calibrating on representative standards, FTIR analysis provides a rapid means of evaluating the oxidative state of an oil or of monitoring changes in oils undergoing thermal stress.
Extraction and characterization ofDimorphotheca pluvialis seed oil
Authors: Muuse Bart G. , Petrus Cuperus F. , Derksen Johannes T. P. 
Published: May 2007

AbstractDimorphotheca pluvialis is increasingly recognized as an interesting industrial new oilseed crop because it contains up to 60% of the unusual fatty acid dimorphecolic acid (9‐hydroxy,10t,12t‐18∶2) (DA) for which new applications are being developed. In this paper, the yield, composition and quality are evaluated for dimorphotheca oils (DMO) which were recovered by pressing, conventional solvent extraction and supercritical carbon dioxide extraction (SCE). Mechanical pressing of the seeds required high temperatures and resulted in an oil recovery of only 40%, whereas the extraction protocols yielded more than 95%. Oil recovery by pressing of winged seed was even more difficult than that of unwinged seeds; hence, solvent extraction of winged seeds was preferred. The dark‐colored DMO, recovered by expelling or by extraction with organic solvents, needed further refining to remove pigments and gums, whereas the light yellow‐colored SCE DMO did not require further refining. SCE oil had a low phospholipid content (11 mg P/kg). Pressed oil (95 mg P/kg) and hexaneor pentane‐extracted DMO (200 mgP/kg) had much higher phospholipid contents. Peroxide andp‐anisidine values were low for freshly recovered oils, but increased after storage, especially in the SCE oil, due to the low concentration of natural antioxidants in SCE DMO, such as tocopherols. The DA content of the oils recovered by the various techniques showed only minor differences, except that supercritical carbon dioxide had slightly decreased solubilizing power for tri‐ and di‐dimorphecolin as compared to hexane and pentane.