bluuebunny/crossref_metadata_2025 huggingface dataset:
Institutional ownership, capital structure, and firm performance
Authors: Chaganti Rajeswararao , Damanpour Fariborz
Published: May 2007

In most studies of ownership and firm performance, researchers have assumed different forms of ownership do not interact in their effect on firm strategy or performance. Focusing on the role of institutional owners, this study poses two related questions: (1) What are the relationships between outside institutional shareholdings, on the one hand, and a firm's capital structure and performance, on the other? and; (2) Does the size of stockholdings by corporate executives, family owners, and insider‐institutions modify those relationships? The data, collected from 40 pairs of manufacturing firms selected from as many industries over a 3‐year period, shows that the size of outside institutional stockholdings has a significant effect on the firm's capital structure. We have also found that family and inside institutional owners' shareholdings moderate the relationship between outside institutional shareholdings and capital structure. Likewise, corporate executives' shareholdings supplement the relationship between outside institutional shareholdings and firms' performance. These findings suggest that internal and external coalitions interact with each other to influence the firm's conduct.
Successful bear‐fighting strategies
Authors: Schreuder Hein , Van Cayseele Patrick , Jaspers Patrick , De Graaff Bert
Published: May 2007

This paper explores the factors involved in determining the differential performance of firms in bear markets. Bear markets are identified at the industry level by employing the criterion of a 20 percent drop of the industrial value added index over a period of at least 3 years. Twenty‐one matched pairs of Dutch firms which have experienced such bear markets (one successful, the other unsuccessful), are analyzed. The dominant finding is that successful firms follow market‐oriented strategies, whereas their unsuccessful counterparts are distinguished by their focus on costs. Success, however, is a multifaceted phenomenon. Differences in initial conditions, in other types of strategic measures, in energy levels and in timing are also involved. The findings are related to the literatures on decline, failure, turnaround and transformation.
Vertical integration in Franchise systems: Agency theory and resource explanations
Authors: Carney Mick , Gedajlovic Eric
Published: May 2007

The ownership strategies of 128 retail franchising systems are examined in the light of existing agency and resource scarcity explanations of this organizational form. Findings suggest that franchiser ownership strategies are more heterogeneous than previously recognized, and that neither explanation, alone accounts for observed ownership patterns. A path model of franchiser ownership patterns embodying agency and resource scarcity elements is developed that is consistent with empirical findings.
Research notes and communications first‐mover effects in multiple dynamic markets
Authors: Mascarenhas Briance
Published: May 2007

A study of first‐mover effects in semi‐submersible oil‐drilling suggests that first‐entrants in international markets maintain higher market share after controlling for market localization and life cycle. Examining only surviving entrants at a point in time inflates this pioneering‐market share relationship. Pioneering has an inter‐market effect on market share, greater than the intra‐market effect. Multinational firms may use market pioneering to resist localization pressures and enhance survival in foreign markets. The study suggests the importance of careful first‐mover identification and market definition, a wider examination of first‐mover effects over multiple markets, and control for measurement timing.
Turnaround: Retrenchment and recovery
Authors: Robbins D. Keith , Pearce John A.
Published: May 2007

Empirical research was conducted to investigate retrenchment as an integral component of the overall turnaround process. An industry study provided an anchored operational definition of a turnaround situation, indications of its internal and external causes, and an application of an absolute measure of its severity. The research further produced an empirical discrimination between retrenchment as a stand‐alone response to financial decline and retrenchment as an initial phase of a turnaround strategy, and an identification of activities that can be used to classify entrepreneurial vs. efficiency emphases in a turnaround firm's recovery response.
Research notes and communications: The effect of product recall announcements on shareholder wealth
Authors: Davidson Wallace N. , Worrell Dan L.
Published: May 2007

Previous research Has found that product recall announcements in the automobile industry are associated with negative abnormal returns. We extend this research by examining announcements of product recalls and products taken off the market outside the automobile industry. We find negative abnormal returns for these announcements and that the returns are significantly more negative when products are replaced (or the purchase price is returned) than when the products are checked and repaired. We find only limited evidence that government‐ordered recalls produce more negative returns than voluntary recalls.
Research notes and communications factors in the instability of international joint ventures: An event history analysis
Authors: Blodgett Linda Longfellow
Published: May 2007

This study uses Event History methodology to examine factors that may contribute to the instability of joint ventures between U.S. multinationals and foreign companies. Using joint venture contract renegotiation as a proxy for instability, it finds statistically significant support for hypotheses that joint ventures are more unstable when partners start out with uneven shares of equity and when the contracts have been renegotiated before. Contract renegotiation is also more likely in relatively open economies than in countries that impose restrictions on direct investment.
Parametric Fortran: program generation in scientific computing
Authors: Erwig Martin , Fu Zhe , Pflaum Ben
Published: May 2007

Parametric Fortran is an extension of Fortran that supports the definition of Fortran program templates by allowing the parameterization of arbitrary Fortran constructs. A Fortran program template can be translated into a regular Fortran program guided by values for the parameters. This paper describes the design, implementation, and applications of Parametric Fortran. Parametric Fortran is particularly useful in scientific computing. The applications include the definition of generic functions, removing duplicated code, and automatic differentiation. The described techniques have been successfully employed in a project that implements a generic inverse ocean modeling system. Copyright © 2007 John Wiley & Sons, Ltd.
Die numerische Quadratur singulärer Funktionalgleichungen
Authors: Marsal D.
Published: May 2007

Das Verfahren gestattet die numerische Quadratur einer umfänglichen Menge singulärer Integranden mit hoher Genauigkeit bei gleichzeitiger, sehr einfacher Berechnung des Quadraturfehlers. Bei der Tabellierung von Integralfunktionen kann die Schrittlänge programmgesteuert so variiert werden, daß eine vorgegebene Fehlerfunktion höchstens geringfügig überschritten wird. Die Beziehungen sind bei gleichem Rechenaufwand und gleich einfacher Handhabung in der Nähe von Singularitäten um Größenordnungen genauer als die klassischen äquidistanten Quadraturformeln. Absolut gesehen und verglichen mit anderen Verfahren ist der vom Benutzer aufzubringende mathematische Aufwand sehr gering. Die Programmierung der Rechenschemata ist einfach. Jedoch ist hohe Genauigkeit an eine große Anzahl von Stützwerten gebunden.
Mehrdimensionale Entscheidungsmodelle
Authors: Gessner P.
Published: May 2007

Es wird über eine numerische Methode zur Lösung von Kontrollproblemen berichtet, bei denen Treppenfunktionen als Steuerfunktionen verwendet werden. (Die verschiedenen Funktionswerte einer Treppenfunktion lassen sich als Entscheidungsfolge deuten.) Eine optimale Steuerung wird iterativ errechnet. Der besondere Vorteil der Methode ist, daß sie bei erträglichem Rechenaufwand auch noch auf Probleme mit mehreren steuernden und gesteuerten Variablen ‐ sogen. mehrdimensionale Modelle ‐ angewandt werden kann.
Zur Darstellung von Lösungen der Gleichung Δφ + (1 + x2 + y2)− φ = 0
Authors: Kracht M. , Kreyszig E.
Published: May 2007

In der vorliegenden Arbeit wird die Differentialgleichung Δφ + c (1 + x2 + y2)−2 φ = 0 betrachtet. Nach einer geeigneten Transformation der Gleichung ergibt sich aus der zugehörigen Riemannschen Darstellung der Lösungen ein Bergman ‐ Operator, dessen Erzeugende in geschlossener Form darstellbar ist. Aus der Bergman ‐ Darstellung der Lösungen wird weiterhin ein von K. W. Bauer und E. Peschl eingeführter Operator hergeleitet.
Über Eigenwerteinschließungen mit Hilfe von Gerschgorin‐Kreisen
Authors: Elsner L.
Published: May 2007

Die Vereinigung gewisser Gerschgorin‐Kreise einer Matrix A sei durch einen Kreis vom Radius r und Mittelpunkt γ von den übrigen Gerschgorin‐Kreisen getrennt. Medley und Varga haben das minimale r, das bei festem γ durch Diagonaltransformationen von A erreicht werden kann, charakterisiert. Es wird gezeigt, daß dieses Ergebnis mit den in einer früheren Arbeit des Autors benutzten Methoden leicht bewiesen werden kann. Außerdem wird der maximale Radius charakterisiert, praktisch verwendbare Abschätzungen angegeben und gezeigt, daß A und die transponierte Matrix AT die gleichen optimalen Radien haben.
Querschwingungen rotierender Seile
Authors: Weidenhammer F.
Published: May 2007

An einer rotierenden Welle befestigte Seile erhalten durch die Fliehkraft eine Steife, die sie zu Querschwingungen befähigt. Es wird gezeigt, daß es zwei zu einander senkrechte Schwingungsrichtungen gibt, in denen entkoppelte Eigenschwingungen möglich sind, deren Eigenfrequenzen und Eigenschwingungsformen sich mit Hilfe der Theorie der Kugelfunktionen berechnen lassen.
Störungsrechnung für lineare gewöhnliche Differentialoperatoren Teil I
Authors: Schmidt A.
Published: May 2007

Die vorliegende Arbeit enthält eine explizite Durchführung der formalen Störungsrechnung für lineare Differentialoperatoren. Die Aufgabe ist äquivalent einem System abzählbar unendlich vieler linearer Eigenwertprobleme.
Analysis of Unloading on a Thin Cirular Plate of Mild Steel Using Actual Unloading Stress‐Strain Relation
Authors: Ohashi Y. , Kawashima K.
Published: May 2007

The actual stress‐strain relation of mild steel in the unloading and subsequent inverse loading processes from plastic state shows a continuous curve without discrete yield point, and its configuration depends on the value of plastic prestrain. In the present paper, in formulating the relation, effective stress in the processes was expressed as a polynomial of the corresponding effective strain in which each coefficient was expressed again as a polynomial of plastic pre‐strain. Then, precise fundamental equations analysing the unloading deformation of a thin circular plate of mild steel are derived by using the above mentioned unloading stress‐strain relation. To examine the validity and applicable range of the derived equations, they are applied to analyse the case of a supported thin circular plate bent by uniform lateral pressure, and the analytical result is compared with that obtained by the corresponding experiment.
Iterations‐, Projektions‐ und Projektions‐Iterationsverfahren zur Berechnung visco‐plastischer Strömungen
Authors: Gajewski H.
Published: May 2007

Mit funktionalanalytischen Methoden werden Näherungsverfahren zur Berechnung von visco‐plastischen Strömungen begründet.
Eine direkte Methode zur numerischen Lösung der Poissonschen Differentialgleichung mit Hilfe des 9‐Punkte‐Verfahrens
Authors: Rózsa P. , Tóth I.
Published: May 2007

Zur numerischen Lösung der ersten und zweiten Randwertaufgabe der Poissonschen Differentialgleichung für Rechteckgebiete wird eine direkte Methode vorgeschlagen. Mit Hilfe des 9‐Punkte‐Verfahrens werden die Differentialgleichungen mit einem Fehler der Größenordnung h6angenähert, wo h die Maschenweite bezeichnet. Die explizite Lösung der so erhaltenen partiellen Differenzengleichungen kann mit der Spektralzerlegung gewisser Hypermatrizen aufgeschrieben werden, da die auftretenden Koeffizientenmatrizen sich als direkte Polynome erweisen.
Viscous‐Magnetic Boundary Layers
Authors: de Socio L.
Published: May 2007

Die Lösung des allgemeinen Problems der viskomagnetischen Grenzschicht wird mit Hilfe asymptotischer Entwicklungen des zugehörigen singulären Störungsproblems behandelt. Dabei werden diejenigen Situationen betrachtet, bei denen sich das Vorhandensein zweier Grenzschichtbereiche erkennen läßt. Die Durchführbarkeit der Methode, die auf Reihenentwicklungen nach Potenzen geeigneter Parameter in jedem Bereich beruht, wird gezeigt.

Im einzelnen wird das magnetofluiddynamische Feld einer ebenen dielektrischen Platte für Größenordnungen der charakteristischen Zahlen behandelt, die dem Fall entsprechen, daß eine viskomagnetische Grenzschicht über der Platte liegt, während sich zwischen der viskomagnetischen Region und der äußeren freien Strömung eine rein magnetische Grenzschicht erstreckt. Die zugehörigen Gleichungen werden gelöst und die Ergebnisse in analytischer Gestalt oder numerisch angegeben.
Abschätzungen für die Wartezeitverteilungen und ihrer Momente beim Wartemodell GI/G/1 mit und ohne „Erwärmung”︁
Authors: Siegel G.
Published: May 2007

Der Autor gibt Abschätzungen für die stationären Wartezeitverteilungen W und W' und für ihre Momente im Bedienungsmodell GI/G/1 bzw. im Modell GI/G/1 mit „Erwärmung”︁ an. Hauptaufgabe sind Abschätzungen für die Verteilung G, die durch die bekannte Darstellung W' = G * W bestimmt ist (s. [10]). Insbesondere beweist der Autor notwendige und hinreichende Bedingungen für die Existenz beliebiger Momente von W, G und W'. Im letzten Abschnitt werden neue Abschätzungen für W und für das erste Moment von W untersucht.
Zur Ermittlung der zirkulationsbehafteten Unterschallströmung eines Tschaplygin‐Gases um ein Kreisprofil
Authors: Schubert H. , Schleiff M.
Published: May 2007

Zur Berechnung der stationären Unterschallströmung eines Tschaplygingases um ein ebenes Profil wurde von M. Grabow eine nichtlineare Integralgleichung hergeleitet, deren numerische Auswertung im zirkulationsbehafteten Fall jedoch Schwierigkeiten bereitete. In der vorliegenden Arbeit werden auf diese Gleichung das Verfahren von Schmidt‐Lichtenstein und das modifizierte Newtonsche Verfahren angewandt, die auch im zirkulationsbehafteten Fall für kreisnahe Profile zu brauchbaren numerischen Ergebnissen führen. Außerdem wird ein Existenzbeweis für streng konvexe Profile hergeleitet.
Zur numerischen Quadratur
Authors: Schmetterer L.
Published: May 2007

Vor kurzem hat Chui eine Quadraturformel mit äquidistanten Knotenpunkten angegeben und gezeigt, daß diese auch bei Anwendung auf nicht‐periodische Funktionen kein „Gibbs'sches Phänomen”︁ aufweist. Diese zunächst überraschende Tatsache beruht aber einfach darauf, daß diese Formel stets als numerisches Integrationsverfahren für eine periodische Funktion angesehen werden kann. Mittels dieser einfachen Bemerkung werden einige Resultate für Funktionen unter geringfügigen Regularitätsvoraussetzungen hergeleitet.
Zur Umkehrung „periodischer”︁ Operatoren
Authors: Berg L.
Published: May 2007

Einige für Operatoren D mit einem rechtsinversen Operator T im linearen Fall aus [4] und im nichtlinearen Fall aus [2] bekannte Operatorformeln werden auf den Fall verallgemeinert, daß D keinen rechtsinversen Operator besitzt. Diese Formeln sind geeignet, um für Operatorgleichungen und Anfangswertprobleme Lösbarkeitsbedingungen zu formulieren und explizite Lösungsformeln bzw. äquivalente Gleichungen, die sich evtl. einfacher lösen lassen, aufzustellen. Die Betrachtungen sind rein algebraischer Natur und setzen voraus, daß die auftretenden Operatoren bekannt sind, so daß es sich hier um qualitative Aussagen handelt. Die Ergebnisse werden an Hand von drei Beispielen aus der linearen Theorie erläutert.
On the Flow of a Non‐Newtonian Fluid past a Porous Flat Plate
Authors: Erdogan M. E.
Published: May 2007

Uniform flow of an Oldroyd fluid B past a porous flat plate is investigated. A third order ordinary differential equation for velocity is solved by the boundary conditions and it is shown that how it is possible to overcome the difficulties occuring in the determination of the constants in the solution. It is found that the velocity depends on the suction parameter, the Deborah number and the ratio of the retardation time to the relaxation time; and it is denoted that how those parameters affect on the velocity profiles. Furthermore, a detailed discussion of boundary conditions is also given.
Über gekrümmte gasdynamische Wellen in stationären ebenen und rotationssymmetrischen Überschallströmungen
Authors: Eckert D.
Published: May 2007

In der vorliegenden Arbeit werden Beziehungen zwischen den Krümmungen von gasdynamischen Wellen und den Gradienten der Zustandsgrößen längs Stromlinien hergeleitet. Es zeigt sich, daß für alle Wellenordnungen die gleichen Beziehungen gelten. Für Folgerungen aus den Gleichungen erweist es sich als zweckmäßig, die Wellen in drei Ordnungen, nämlich Verdichtungsstöße. Gradientenwellen und Wellen höherer Ordnung, einzuteilen. Ergebnisse von Anwendungen der Krümmungsbeziehungen werden mitgeteilt und insbesondere die gegenseitige Beeinflussung von Verdichtungsstößen und Gradientenwellen, die von unstetigen Krümmungsänderungen in Körperkonturen ausgehen, untersucht.
Die niederfrequent instationäre Druckverteilung an Flügelprofilen in gashaltiger Wasserströmung
Authors: Isay W. H. , Roestel Th.
Published: May 2007

In der vorliegenden Arbeit wird die ebene niederfrequent instationäre Strömung von gashaltigem Wasser um Tragflügelprofile behandelt. Unter dem Begriff Gas verstehen wir dabei sowohl die im Wasser enthaltene ungelöste Luft als auch den durch Kavitation bedingten Wasserdampf. Zur Vereinfachung der Theorie ist die Eigenbewegung der Gasblasen gegenüber dem umgebenden Wasser vernachlässigt; ferner ist vorausgesetzt, daß das Verhältnis von Gasmasse zu Wassermasse eine eindeutige Funktion des örtlichen Druckfeldes sei. Durch die Beschränkung auf niederfrequent instationäre Vorgänge ist es möglich, die Änderung der Strömungsgrößen bei auftretenden Verdichtungsstößen aus den stationären Stoßrelationen zu ermitteln. Im übrigen stellt die vorliegende Theorie die konsequente Verallgemeinerung einer bereits früher veröffentlichten Methode zur Behandlung stationärer Profilströmungen dar. Die Ergebnisse von Zahlenbeispielen werden diskutiert. Es zeigt sich, daß die durch den Gasgehalt im Wasser bedingte Modifikation der Druckverteilung gegenüber dem inkompressiblen Zustand für niederfrequent instationäre Strömungen ähnlich ist wie im stationären Fall. Insbesondere kommt es nur dann zu nennenswerten Abweichungen vom inkompressiblen Druckfeld, wenn lokale Überschallbereiche mit Verdichtungsstößen auftreten.
Über pauschale Fehlerschranken für Approximationen von Schalenverformungen
Authors: Antes H.
Published: May 2007

Basierend auf der statisch‐geometrischen Dualität werden obere und untere Schranken für die Energie einer gesuchten Feldgröße konstruiert. Der unbekannte Zustand wird durch geometrisch bzw. statisch zulässige Zustände angenähert, deren noch freie Koeffizienten durch Minimierung der Fehlerenergie bestimmt werden.
An Asymptotic Method in the Field of Nonlinear Oscillations
Authors: Cheshankov B. I.
Published: May 2007

A generalization of Struble's method is given. A general scheme of this generalized method is given and it is shown that in fact this method is one of the possible schemes of the averaging method. The calculation of integrals in the averaging method here is replaced by the employing of specific trigonometrical identities. This is also proof of the mathematical basis of the method since the averaging method is mathematically wellgrounded.
An Estimation of the Lower Stability Limit of the Free Edge Orthotropic Cylindrical Shell in Axial Compression
Authors: el Naschie M. S.
Published: May 2007

The paper presents a simplified calculation for the minimum load carrying capacity of a free edge cylindrical shell in axial compression.
The Unsteady Forces on Flat‐Plate‐Airfoils in Cascade Moving through Sinusoidal Gusts
Authors: Murata S. , Tsujimoto Y.
Published: May 2007

This paper presents an analysis for the determination of the lift fluctuation on flat‐plate‐airfoils in cascade due to transverse and chordwise gusts. The acceleration potential method is used in combination with conformal mapping method. This method gives an utterly simple analysis even for cascades, without the complicated integral equations enevitable for the determination, of vortex distribution in velocity‐field analysis. The computational results show that the pitch and the stagger angle of the cascade have much influence upon the magnitude of the fluctuating lift, but not so much upon phase angle.
Eine Klasse isotroper Turbulenzfelder mit Permanenzeigenschaft und existenten Tripelkorrelationen
Authors: Schultz‐Piszachich W.
Published: May 2007

Es wird eine Klasse isotroper Turbulenzfelder eingeführt, die allen Forderungen an die Zwei‐ und Dreifachkorrelationsfunktionen der Geschwindigkeiten, insbesondere der v. Kármán‐Howarth‐Differentialgleichung, genügt. Dir Energiespektralfunktionen lassen sich mit einer Klasse ganzer rationaler Funktionen leicht berechnen. Die Mikro‐ und Makrogrößen der eingeführten „idealen”︁ Turbulenzfelder werden ermittelt. Jedes Turbulenzfeld der „idealen”︁ Feldklasse besitzt eine Loitsianskiische Zeitinvariante und existente Dreifachkorrelationen, die nur im Grenzfall des Spezialfeldes von Loitsianskii identisch verschwinden. Besondere Grenzwertbeziehungen ergeben sich für die Makrolängenmaße, die Zeitinvarianten und Energiespektralfunktionen. Physikalisch wird das Spätstadium der Turbulenz bei kleinen Reynoldszahlen betrachtet.
Viscous Transonic Flow in Relaxing Gases
Authors: Sichel M. , Yin Y. K.
Published: May 2007

The equations for the plane viscous transonic flow of a relaxing gas are derived for free stream velocities near the equilibrium and frozen speeds of sound. One‐dimensional solutions are found which show the influence of the compressive viscosity upon the structure of a compression wave in a relaxing gas. The viscous structure of the corner region or acceleration wave which occurs when the upstream velocity just equals the frozen speed of sound is investigated in detail. The structure of a partially dispersed wave including the transition from the upstream viscous shock to the downstream relaxation zone is also determined.
Optimierungstheoretische Behandlung diskreter linearer Tschebyscheffscher Approximationsprobleme
Authors: Juhnke Friedrich
Published: May 2007

Es werden die speziellen Strukturen der linearen Optimierungsprobleme untersucht, die zu diskreten linearen Tschebyscheffschen Approximationsproblemen gehören. Dazu wird der Begriff der „Korrespondenz„ zwischen Variablen, Restriktionen, Basen und Lösungen eingeführt und der Entartungsfall genauer behandelt. Es werden Eigenschaften dieser Korrespondenz angegeben, mit Hilfe derer gezeigt wird, wie sich unter alleiniger Benutzung von optimierungstheoretischen Hilfsmitteln Aussagen über diskrete Tschebyscheff‐Probleme herleiten lassen, z. B. Haarsche Eindeutigkeitsaussagen. ein Charakterisierungstheorem nach Cheney, Aussagen über die Anzahl der Extremalgleichungen der Tschebyscheff‐Punkte in Abhängigkeit vom Rang der Koeffizientenmatrix.
Stabilitätsgleichungen elastischer Flächentragwerke unter besonderer Beachtung der Energieerhaltung
Authors: Fritz H. , Krätzig W. B. , Wittek U.
Published: May 2007

Ausgehend von Prinzip der Energieerhaltung werden die Stabilitätsgleichungen dünner elastischer Schalen unter Anwendung der Gleichgewichtsmethode hergeleitet. Dabei wird der Weg einer Integraltransformation des ursprünglich dreidimensionalen Körpers zu einem sogenannten Schalenkontinuum eingeschlagen, das mittels einer bekannten Definition zur dünnen Schale approximiert wird. Formale Widersprüche des Ableitungsganges können mit Hilfe der Stabilitätskriterien von Ljapunow erkannt und beseitigt werden. Die erhaltene lineare Stabilitätstheorie besitzt den Charakter einer bestmöglichen flächenhaften Approximation.
Parametric Random Excitation of a Damped Mathieu Oscillator
Authors: Ariaratnam S. T. , Tam D. S. F.
Published: May 2007

The effect of parametric random excitation on the moment stability of a damped Mathieu oscillator is investigated. Conditions for stability of the first and second moments of the response are obtained when the harmonic excitation lies in the neighbourhood of twice the natural frequency of the oscillator. It is found that the presence of the additional parametric random excitation can cause either a stabilizing or a destabilizing effect depending on the values of certain parameters of the random excitation. In particular, it is shown that parametric excitation by white noise has no effect on the first moments of the response but has a destabilizing effect on the second moments. For the case of exponentially correlated noise, regions of instability are shown in graphical form.
Zur Torsion zusammengesetzter Stäbe
Authors: Windisch E.
Published: May 2007

Das Torsionsproblem für Stabe, die aus einer Anzahl prismatischer Teilstäbe unterschiedlicher Werkstoffe zusammengesetzt sind, wird auf ein System von Fredholmschen Integralgleichungen zurückgeführt. Für das Problem wird eine numerische Lösungsmethode angegeben, die für beliebige Querschnittsarten anwendbar ist. Die Anwendbarkeit dieser Methode wird an Hand von Beispielen gezeigt.
Eine Lösung für das Problem des Wärmeaustauschs einer Kugel in gleitender Umströmung
Authors: Asseng E.
Published: May 2007

Verdünnte Gase gleiten an der Oberfläche umströmter Körper. Das Geschwindigkeitsfeld in der Umgebung einer Kugel im Kontinuum, wo Haften an der Oberfläche vorausgesetzt ist, wird auf der Grundlage der Lösung von Stokes für kleine Reynolds‐Zahlen für Gleitströmung verallgemeinert, indem ein Gleitfaktor eingeführt wird. Aus dem Geschwindigkeitsfeld wird die Reibungsdissipation in Kugelkoordinaten berechnet, sie bildet mit der Wärmeleitung im Gas die Energiebilanz, aus deren Lösung sich die Wärmeaustauschparameter Rückgewinnfaktor und Nusselt‐Zahl ergeben. In die Lösung wird der Temperatursprung an der Kugeloberfläche, eine weitere charakteristische Erscheinung der Gleitströmung, einbezogen.
The preparation and properties of some nitrogen‐containing derivatives of petroselinic acid
Authors: Placek Lida L. , Dollear F. G.
Published: May 2007

Petroselinonitrile was prepared by distilling the ammonolysis products of petroselinic acid over phosphorus pentoxide, and also from parsley seed oil without first isolating the petroselinic acid. A high‐boiling antioxidant was employed during the reaction to control polymerization. The reaction by‐products were segregated from the pure petroselinonitrile by urea complexing. Petroselinamide was obtained from petroselinic acid by the acidolysis of urea. Although it was not possible to reduce the petroselinonitrile by catalytic hydrogenation without affecting the ethylenic linkage or without producing a mixture of the primary, secondary, and tertiary amines, petroselinonitrile was converted to primary petroselinylmine in good yields by reduction with metallic sodium and alcohol in toluene. The hydrochloride and the acetyl derivative of the pure primary amine have also been prepared.
Extraction of soybeans with four hydrocarbon solvents
Authors: Arnold Lionel K. , Choudhury R. Basu Roy
Published: May 2007

Soybean flakes were extracted in glass extraction apparatus with four hydrocarbon solvents: hexane, isohexane, pentane, and isopentane. The amount of extracted oil was determined at 10 min intervals for 60 min. The extraction rates of the solvents increased in the following order: isopentane, pentane, isohexane, and hexane. Quality and fatty acid composition of the oils extracted by the four solvents showed no significant differences.
The kinetics of the oxidation of several antioxidants in oxidizing fats
Authors: Lundberg W. O. , Dockstader W. B. , Halvorson H. O.
Published: May 2007

The deterioration of hydroquinone, catechol, NDGA (nordihydroguaiaretic acid), and gallic acid in lard oxidizing at 100° C. has been quantitatively studied. Initial concentrations of 0.02, 0.1, and 0.5% were used.

The results indicate that, in general, the deterioration of phenolic antioxidants in oxidizing fats does not occur as a single low order reaction but is complicated by products formed in the oxidation of the fat and possibly also of the antioxidant.

The deterioration curves for gallic acid are quite different from those of the other three antioxidants. This is tentatively explained on the basis of the synergistic action of gallic acid upon itself.

There is an increasing catalytic effect with increasing initial concentrations of all of these antioxidants on the formation of peroxides during the early stages of the autoxidation of lard.
Decolorization of tallow by liquid‐liquid extraction with propane
Authors: Moore E. B.
Published: May 2007

Conclusion

The decolorization of tallow by liquid‐liquid extraction in propane is a significant advance in the treatment of tallows. It greatly surpasses the effectiveness of bleaching earths and chemical bleaches such as have been in use for many years.
Safflower oil
Authors: Winter G.
Published: May 2007

A brief account is given of experiments with safflower oil in Australia. Under practical conditions, the drying power of safflower oil equals that of linseed oil. The non‐yellowing properties of the former render it superior to the latter as a vehicle in coatings for interior decoration and in stoving enamels. In the heat polymerization of safflower oil, temperatures 10° to 15°C. higher than those normally employed for linseed oil are recommended. During three years of outdoor exposure trials, paints based on safflower oil have performed at least as well as similar paints from linseed oil. The commercial production of the oil by solvent extraction presents no difficulty. Decortication prior to extraction is not necessary. The resulting oil has a very good colour and is free from “foots.” On alkali refining, losses are very small. Notwithstanding the high hull content of the meal, it has proved valuable as a stock fodder.
X‐ray diffraction analysis of synthetic unsaturated diacid diglycerides
Authors: Benedict James H. , Sidhu S. S. , Daubert B. F.
Published: May 2007

Chemical and physical data are reported for the three diacid 1,3‐diglycerides obtainable from stearic, oleic, and elaidic acids. Two of these are new, namely 1‐stearyl‐3‐elaidin and 1‐oleyl‐3‐elaidin.

X‐ray data have revealed one form for 1‐oleyl‐3‐elaidin and two forms for the other two diglycerides, with considerable individuality in the diffraction patterns of the compounds.
Solvent extraction. III. The effect of particle size on extraction rate
Authors: Coats H. B. , Wingard M. R.
Published: May 2007

Quantitative data have been presented for the effect of “effective extraction size” on the rate of extraction of oil from soybeans, peanuts, cottonseed, corn germ grits, and flaxseed. Both flakes and grits have been studied. The results are best correlated by a straight‐line plot on log‐log paper of “time to 1% residual” and effective extraction size. The slope of the line is a measure of the change in extraction rate with extraction size. The slope was found to be different for the different oil seeds and to be larger for seeds prepared as grits than for the same seed prepared as flakes.
Reactions of tertiary butyl hypochlorite with vegetable oils and their derivatives. III. Chlorination of soybean oil in the pilot plant
Authors: Bell E. W. , Teeter H. M.
Published: May 2007

Batches of soybean oil weighing up to 54 pounds have been chlorinated withtert‐butyl hypochlorite in conventional pilot‐plant equipment.

The chlorinated oil was dehydrochlorinated in an all‐glass apparatus designed for continuous operation. Excellent results were obtained when chlorinated oil was passed through this apparatus at a rate of 1.5 liters per hour.

The properties of the dehydrochlorinated oil were equivalent to those of oils previously obtained by laboratory procedures.
Metal deactivation in lard
Authors: Morris S. G. , Myers J. S. , Kip Mary L. , Riemenschneider R. W.
Published: May 2007

A number of compounds, including known synergists, amino acids, and amines, have been evaluated as deactivators for copper, iron, nickel, and tin in lard. Some were effective in deactivating copper but were relatively poor for iron. One compound was better for iron than for copper.

Ascorbyl palmitate, potassium ascorbyl palmitate, and ascorbic, tartaric, citric, and phosphoric acids were the most effective. This deactivation may in part explain the synergistic effect of these compounds with phenolic antioxidants.

The more powerful antioxidants however are generally poor metal deactivators, and in the presence of traces of metallic pro‐oxidants become relatively ineffective unless metal deactivators are also added.
Factors involved in the spectrophotometric analysis of fats
Authors: Potter George C. , Kummerow Fred A.
Published: May 2007

The presence of nonsaponifiable material in lipids can cause appreciable differences in calculated mixed fatty acid content. The error can be appreciable in lipids extracted from liver unless a saponification and extraction procedure is included in the method. Skin, gizzard, and depot fats do not contain high concentrations of nonsaponifiable material. However chicken skin fat contains a yellow pigment which absorbs ultra violet radiation. This pigment, while not present in a large amount, can still cause errors in the spectrophotometric analysis. It can best be separated from the mixed fatty acids by distillation of the methyl esters.

The equations developed by previous workers have been recalculated on the basis of an arachidonic acid of 99.3% purity. These equations are suggested for use in the spectrophotometric analysis of unsaturated fatty acids.
The determination of borax in soap
Authors: Bernstein Rubin , Haftel Martin
Published: May 2007

Based on the data presented, it is considered that the present method is superior to both the federal specification and Blank and Troy procedures in terms of more complete recovery of borax, better reproducibility, and shorter time required for analysis.

The present method differs from the Blank and Troy method in two essential features, namely, simultaneous removal of soap and silicates, phosphates, and carbonates by precipitation with strontium ion, and use of methyl purple instead of methyl red indicator during adjustment of the acidity of the solution prior to final titration with standard alkali. These differences are believed responsible for the more accurate and reproducible results obtainable by the present method as compared with those given by the Blank and Troy procedure.

It should be noted that the above procedure is limited to soaps and/or alkaline builders and cannot be applied to synthetic detergents that do not precipitate with strontium.
Solvent extraction. II. The soaking theory of extractions
Authors: Coats H. B. , Karnosky George
Published: May 2007

The extraction process within the oil‐bearing substance is described in terms of undissolved oil and static holdup. Undissolved oil is bound in the original material through a slowly soluble resistance that is not re‐established by replacing the extracted oil. The rate of solution of the oil is relatively indepenent of the concentration of the extracting solution and is mainly a matter of soaking time. Soaking in anay concentration of miscella below 20% for half the total extraction time required to reduce the undissolved oil to 1% is just as effective as extraction for the entire time with fresh solvent.
Molecularly distilled monoglycerides. II. Cake baking experiments
Authors: Kuhrt Noel H. , Welch Eileen A.
Published: May 2007

Different types of monoglycerides have been shown to possess marked differences in their activity in cake baking. Improved activity has been observed when the monoesters made from fats containing unsaturated acids were used. The activity of a distilled monoglyceride would be expected to be proportional to its monoester content or about 2.2 times more active than the reaction mixture. It has been shown however that, at practical concentrations in an experimental cake, the distilled monoesters were considerably more active than expected. This greater activity has been shown to be due primarily to the absence of the diester.
Temporal and spatial incidence of alleles conferring knockdown resistance to pyrethroids in the peach–potato aphid,Myzus persicae(Hemiptera: Aphididae), and their association with other insecticide resistance mechanisms
Authors: Anstead J.A. , Mallet J. , Denholm I.
Published: May 2007

The peach–potato aphid,Myzus persicae(sulzer), is an important arable pest species throughout the world. Extensive use of insecticides has led to the selection of resistance to most chemical classes including organochlorines, organophosphates, carbamates and pyrethroids. Resistance to pyrethroids is often the result of mutations in thepara-type sodium channel protein (knockdown resistance orkdr). InM. persicae, knockdown resistance is associated with two amino-acid substitutions, L1014F (kdr) and M918T (super-kdr). In this study, the temporal and spatial distributions of these mutations, diagnosed using an allelic discriminating polymerase chain reaction assay, were investigated alongside other resistance mechanisms (modified acetylcholinesterase (MACE) and elevated carboxylesterases). Samples were collected from the UK, mainland Europe, Zimbabwe and south-eastern Australia. Thekdrmutation and elevated carboxylesterases were widely distributed and recorded from nearly every country. MACE andsuper-kdrwere widespread in Europe but absent from Australian samples. The detection of a strongly significant heterozygote excess for bothkdrandsuper-kdrthroughout implies strong selection against individuals homozygous for these resistance mutations. The pattern of distribution found in the UK seemed to indicate strong selection against thesuper-kdr(but not thekdr) mutation in any genotype, in the absence of insecticide pressure. There was a significant association (linkage disequilibrium) between different resistance mechanisms, which was probably promoted by a lack of recombination due to parthenogenesis.
Distribution of common genotypes ofMyzus persicae(Hemiptera: Aphididae) in Greece, in relation to life cycle and host plant
Authors: Blackman R.L. , Malarky G. , Margaritopoulos J.T. , Tsitsipis J.A.
Published: May 2007

Microsatellite genotyping was used to identify common clones in populations of theMyzus persicaegroup from various hosts and regions in mainland Greece and southern Italy and to compare their distribution and occurrence on tobacco and other crops. Common clones were defined as genotypes collected at more than one time or in more than one population; and, therefore, unlikely to be participating in the annual sexual phase on peach. Sixteen common genotypes were found, accounting for 49.0% of the 482 clonal lineages examined. Eight of these genotypes were subjected, in the laboratory, to short days and found to continue parthenogenetic reproduction, i.e. they were anholocyclic. Four of the six commonest genotypes were red, and one of these accounted for 29.6% of the samples from tobacco and 29.4% of those from overwintering populations on weeds. All six commonest genotypes were found on weeds and five of them both on tobacco and on other field crops. In mainland Greece, the distribution of common clones corresponded closely with that of anholocyclic lineages reported in a previous study of life cycle variation. Common genotypes were in the minority in the commercial peach-growing areas in the north, except on weeds in winter and in tobacco seedbeds in early spring, but predominated further south, away from peach trees. This contrasts with the situation in southern Italy, reported in a previous paper, where peaches were available for the sexual phase, yet all samples from tobacco were of common genotypes.
Termite colony ontogeny: supplemental data in the long-term assessment of reproductive lifespan, female neotenic production and colony size in Reticulitermes flavipes (Isoptera: Rhinotermitidae)
Authors: Long C.E. , Thorne B.L. , Breisch N.L.
Published: May 2007

Reticulitermes flavipes (Kollar) colonies established by field-collected alates were reared in the laboratory for 11 years. Weights of members of each caste and full-colony censuses were performed regularly; the most recent 2003–2004 data are reported. Colonies averaged 11623.5±910 individuals, and with the exception of primary queens from one genetic lineage, mean weights for all castes had increased since 2001. Female replacement reproductives, or neotenics, developed to replace dead queens in clusters of either few, large individuals or many, small individuals. Regardless of cluster size, female neotenics comprised more reproductive biomass per colony than primary queens. The number and size of female neotenics was independent of colony size or time elapsed since a founding queen's death.
Pupal diapause ofHelicoverpa armigera(Lepidoptera: Noctuidae): sensitive stage for thermal induction in the Okayama (western Japan) population
Authors: Kurban A. , Yoshida H. , Izumi Y. , Sonoda S. , Tsumuki H.
Published: May 2007

Helicoverpa armigera(Hübner) exhibits a facultative pupal diapause, which depends on temperature and photoperiod. Pupal diapause is induced at 20°C by short photoperiods and inhibited by long photoperiods during the larval stage. However, in some pupae (35% of males and 57% of females) of a non-selected field population from Okayama Prefecture (34.6°N), diapause is not induced by short photoperiods. In the present experiment, the importance of temperature for diapause induction was studied in the non-diapausing strain, which was selected from such individuals reared at 20°C under a short photoperiod of 10L:14D. Furthermore, the sensitive stage for thermal determination of pupal diapause was determined by transferring larvae of various instars and pupae between 20°C and 15°C. Diapause was induced by 15°C without respect to photoperiod. When larvae or pupae reared from eggs at 20°C under a short or a long photoperiod were transferred to 15°C in the periods of the middle fifth instar to the first three days after pupation, the diapause induction rate was significantly reduced in both males and females, especially in females. In contrast, when larvae or pupae reared at 15°C were transferred to 20°C in the same periods, diapause was induced in males, but not in females. However, the diapause induction rate of pupae transferred to 20°C on the fourth day after pupation was significantly increased in females. The results show that temperature is the major diapause cue in the photoperiod-insensitive strain and the periods of middle fifth larval instar to early pupal stage are the thermal sensitive stages for pupal diapause induction with some different responses to temperatures between males and females inH. armigera.
Utilizing the assassin bug, Pristhesancus plagipennis (Hemiptera: Reduviidae), as a biological control agent within an integrated pest management programme for Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton
Authors: Grundy P.R.
Published: May 2007

Helicoverpa spp. and mirids, Creontiades spp., have been difficult to control biologically in cotton due to their unpredictable temporal abundance combined with a cropping environment often made hostile by frequent usage of broad spectrum insecticides. To address this problem, a range of new generation insecticides registered for use in cotton were tested for compatibility with the assassin bug, Pristhesancus plagipennis (Walker), a potential biological control agent for Helicoverpa spp. and Creontiades spp. Indoxacarb, pyriproxifen, buprofezin, spinosad and fipronil were found to be of low to moderate toxicity on P. plagipennis whilst emamectin benzoate, abamectin, diafenthiuron, imidacloprid and omethaote were moderate to highly toxic. Inundative releases of P. plagipennis integrated with insecticides identified as being of low toxicity were then tested and compared with treatments of P. plagipennis and the compatible insecticides used alone, conventionally sprayed usage practice and an untreated control during two field experiments in cotton. The biological control provided by P. plagipennis nymphs when combined with compatible insecticides provided significant (P<0.001) reductions in Helicoverpa and Creontiades spp. on cotton and provided equivalent yields to conventionally sprayed cotton with half of the synthetic insecticide input. Despite this, the utilization of P. plagipennis in cotton as part of an integrated pest management programme remains unlikely due to high inundative release costs relative to other control technologies such as insecticides and transgenic (Bt) cotton varieties.
Supplemental food affects thrips predation and movement of Orius laevigatus (Hemiptera: Anthocoridae) and Neoseiulus cucumeris (Acari: Phytoseiidae)
Authors: Skirvin D.J. , Kravar-Garde L. , Reynolds K. , Jones J. , Mead A. , Fenlon J.
Published: May 2007

Two experiments were done to examine the predation of thrips, and the movement of Orius laevigatus Fieber and Neoseiulus cucumeris (Oudemans) in the presence and absence of two supplemental food sources, pollen and the fungus Trichoderma viride. The presence of pollen led to a 55% reduction in predation of the thrips by N. cucumeris and a 40% reduction in thrips predation by O. laevigatus, in experiments using single predators. The presence of fungus had no significant effect on thrips predation by either of the natural enemy species. Movement of the natural enemies was examined in a multiple predator experiment, and this showed that O. laevigatus was more likely to remain on the plant in the presence of thrips and when supplemental food, either pollen or fungus, was present. For N. cucumeris, there was no association between the presence of thrips and the mite, with the majority of the mites being found on the leaves where pollen was present. Although the single and multiple predator experiments were done at different times, the indications are that the predation rates of the N. cucumeris do not differ greatly between the two experiments, suggesting that there may be a potential interference effect between the mites, which is not present for O. laevigatus. The significance of these results for the use of supplemental food sources in biological control is discussed.