bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laminare, instationäre Strömung im Ringraum zwischen zwei Rohren, von denen das innere harmonisch schwingt
Authors: Farah M. N. 
Published: June 2007

AbstractIn dieser Arbeit wird untersucht, wie die laminare Strömung im Ringraum zwischen zwei Rohren von der harmonischen Schwingung des Innenzylinders beeinflußt wird. Im Rahmen einer Störungsrechnung zweiter Ordnung wird die Durchflußmenge und die Leistung des schwingenden Innenzylinders errechnet. Die Rechnung ergibt: a) Bei sehr langsamen Schwingungen (quasistatischer Fall) erhöht sich der Durchfluß gegenüber der konzentrischen Ruhelage. Durch wachsendes Radienverhältnis × = r1/r2* wird dieser Effekt verstärkt. Der Grenzwert ω → 0 wird mit der exakten Lösung von Cardwell verglichen. b) Für höhere Frequenzen mindert sich der Durchfluß, bis ein Minimalwert erreicht wird, der weit unter dem Durchfluß bei konzentrischer Ruhelage liegt. c) Für sehr hohe Frequenzen steigt der Durchfluß wieder allmählich an, bis er asymptotisch einen Wert erreicht, der noch unter der Ruhelage liegt. d) Die erforderliche Leistung/Länge L zur Aufrechterhaltung der vorgegebenen harmonischen Schwingung des Innenzylinders wächst mit steigender Frequenz.
Potentialdarstellung einer asymptotischen Lösung der Gleichung ΔΔu–x2Δu = f
Authors: Mazilu P. 
Published: June 2007

AbstractPotentialtheoretische Methoden werden angewendet bei der Untersuchung der singulären Störungen der harmonischen und biharmonischen Differentialgleichung. Mit Hilfe dieser Methoden kann die Johnsche Grenzschichtabschätzung für homogene Gleichungen erhalten werden. Die harmonische Funktion, die man bei dieser Abschätzung findet, wird bestimmt durch eine Funktionalgleichung in Raum der harmonischen Funktionen. Außerdem wird auch die Ausdehnung dieses Ergebnisses auf inhomogene Gleichungen möglich.
Coupled Thermoelastic Problem in Three‐Dimensions
Authors: Tanigawa Y. , Takeuti Y. 
Published: June 2007

AbstractA new technique is proposed to the coupled thermoelastic problems in three‐dimensions. In the basic relations we introduce an additive harmonic function and then it is possible to separate both thermal and elastic fundamental differential equations Taking advantage of this technique we will be able to obtain the exact solution for the whole time range in the three‐dimensional transient thermal stress problem of a circular cylinder. Several numerical results in temperature and stress distribution are given for the sake of comparison to the classical results.
Response of a Multidegree‐of‐Freedom System of Variable Coefficients to Random Excitation
Authors: Szopa J. 
Published: June 2007

AbstractThis paper presents a method of determining probabilistic characteristics concerning the response of a multidegree‐of‐freedom system with variable coefficients to random excitation. This method is based on the application of a stochastic Volterra integral equation of the second kind and not on the multidegree impulsive response (Green's function) difficult to calculate for this type of the systems. On the Basis of the suggested method there have been carried out numerical calculations concerning the variance of the response of the two‐degree‐of‐freedom system with variable mass.
Conservation Laws for a Dynamical System in Group Variables
Authors: Hussain M. 
Published: June 2007

AbstractIn this paper we consider a conservative dynamical system whose position is specified by group variables and the Lagrangian for which is a function of the time derivatives of the parameters of real displacement. After obtaining the Euler‐Lagrange equations for the system, a generalisation of the fundamental invariance identities has been done which is further used to establish Noether' theorem. At the end necessary and sufficient conditions are derived for parameter invariance. The theory is based upon the concept of a mechanical system but the results obtained can be applied to all problems in mathematical physics admitting a Lagrangian function.
Anwendung eines direkten Verfahrens zur numerischen Behandlung von selbstadjungierten, positiv definiten Eigenwertaufgaben bei linearen gewöhnlichen Differentialgleichungen mit stückweise stetigen Koeffizientenfunktionen
Authors: Dähnn J. 
Published: June 2007

AbstractFür eine Klasse von Eigenwertaufgaben bei linearen gewöhnlichen Differentialgleichungen mit stückweise stetigen Koeffizientenfunktionen wird die Anwendbarkeit einer direkten numerischen Lösungsmethode nachgewiesen, bei der die Eigenwerte als Nullstellen einer transzendenten charakteristischen Gleichung erhalten werden. Zur Berechnung von werten der charakteristischen Funktion wird für Differentialgleichungen zweiter Ordnung ein numerisch stabiler Algorithmus angegeben. Praktische Rechnungen für die Hillsche Differentialgleichung zeigen, daß sich das Ritzsche Verfahren bei der Berechnung der kleinsten Eigenwerte und das direkte Verfahren bei der Berechnung der größeren Eigenwerte hinsichtlich ihrer guten numerischen Eigenschaften ergänzen.
The Boundary Integral Equation Method for Plates Resting on a Two‐Parameter Foundation
Authors: Balaš J. , Sládek V. , Sládek J. 
Published: June 2007

AbstractIn the paper the boundary integral equation method for solving the problem of a plate resting on a two‐parameter foundation is presented. Three boundary value problems are considered, and three cases are to be distinguished as regards a characteristic parameter of the foundation. The boundary integral equation solution for a clamped circular plate under a concentrated load is compared to the analytical one.
Zur analytischen Lösung geometrischer Optimierungsaufgaben mittels Dualität bei Steuerungsproblemen. Teil II
Authors: Andrejewa J. A. , Klötzler R. 
Published: June 2007

AbstractIm Teil I der gleichlautenden Arbeit wurden Grundlagen zur Dualität bei Steuerungsproblemen bereitgestellt und auf zwei geometrische Optimierungsprobleme angewandt: Die Bestimmung ebener konvexer Bereiche größten bzw. kleinsten Umfangs bei vorgegebener Dicke Δ und vorgeschriebenem Durchmesser D. Im vorliegenden Teil II schließt sich unter gleichen Nebenbedingungen die Behandlung zweier weiterer Beispiele an: Das Problem des ebenen konvexen Bereichs größten Flächeninhalts und des konvexen Körpers größter Oberfläche.
Explicit Error Estimates for Difference Schemes Solving the Stationary Constant Coefficient Diffusion‐Convection‐Reaction Equation
Authors: Stoyan G. 
Published: June 2007

AbstractSome difference schemes for the cited (stationary) equation are considered and their accuracy is estimated by known quantities only. The results are useful for any Peclét number and imply uniform convergence (with respect to a small diffusion coefficient) up to forth order in h in the linear case and of first order in the mildly nonlinear case.
Materialgleichungen zur Beschreibung des sekundären und tertiären Kriechverhaltens anisotroper Stoffe
Authors: Betten J. 
Published: June 2007

AbstractIn diesem Artikel werden Konstitutivgleichungen für das sekundäre und tertiäre Kriechstadium eines anisotropen Materials formuliert. Zur Untersuchung des sekundären Kriechverhaltens wird die Existenz eines Kriechpotentials angenommen. Unter Berücksichtigung der Darstellungstheorie für Tensorfunktionen liefert die Kriechpotentialhypothese nur eingeschränkte Formen der Konstitutivgleichungen auch bei Annahme eines allgemeinen Kriechpotentials für den anisotropen Fall. In der tertiären Phase wird der Kriechprozeß durch einen Schadenstensor charakterisiert. Es werden einige mögliche Darstellungen der Konstitutivgleichungen diskutiert unter Einbeziehung einer (Anfangs‐) Anisotropie des Materials (i.a. durch Walzen) und eines anisotropen Kriechschadens. Diese Gleichungen werden aufgrund von Theoremen für tensorwertige Tensorfunktionen formuliert.
Dynamic Investigation of Multi‐Mass Drive System by Means of Torsional Waves. Part I: Formulation of the Problem and Numerical Solution
Authors: Nadolski W. , Pielorz A. , Mioduchowski A. 
Published: June 2007

AbstractIn the paper the continuous model of a multi‐mass drive system is considered. The method of dynamical analysis is based on the theory of propagation of one‐dimensional torsional elastic waves. Discussion is presented for the system consisting of N shafts and N + 1 rigid bodies. Numerical results for a system consisting of 2 shafts and 3 rigid bodies are presented in graphical form.
Modified Propagation of Ultrasonic Surface Waves by Thin Elastic or Viscous Films
Authors: Schultrich B. 
Published: June 2007

AbstractThe mechanical properties of thin films often differ from those of bulk material and depend on technological parameters. But they can be determined in the coating‐substrate composite directly by means of ultrasonic surface waves. For thin layers in relation to wavelength, the displacement field within the layer is expanded in powers d/Λ. The corresponding equation system given for the general case is evaluated for elastic and viscous coatings in lowest order of d/Λ. An elastic covering layer causes a relative change in velocity proportional to ω η d where the factor is determined by the elastic and inertial differences between film and substrate. By a viscous coating the surface wave is attenuated proportional to ω3ηd. The elastic case confirms in the first order the results of a plate theory approximation given formerly by Achenbach and Keshava. However, their higher order terms prove to be incomplete from the viewpoint of the present systematic expansion.
Eigenwertschranken für Eigenwertaufgaben mit partiellen Differentialgleichungen
Authors: Goerisch F. , Haunhorst H. 
Published: June 2007

AbstractBetrachtet werden Eigenwertaufgaben Mφ = ΛNφ, wobei M und N symmetrische lineare Operatoren in einem Prähilbertraum sind. Zur Berechnung von unteren Schranken für die Eigenwerte wird ein neues Verfahren vorgeschlagen. Es wird an Hand der Aufgabe

erläutert, die bei der Bestimmung von Beulwerten eingespannter rechteckiger Platten auftritt; für den kleinsten positiven Eigenwert werden genaue untere und obere Schranken angegeben. Das vorgeschlagene Verfahren ist eng mit einer von N. J. Lehmann entwickelten Methode verwandt, es kann aber sehr viel leichter auf Eigenwertaufgaben Mφ = ΛNφ angewandt werden, bei denen M und N partielle Differentialoperatoren sind.
Stability of Cylindrical Shells, by Various Nonlinear Shell Theories
Authors: Simitses G. J. , Shaw D. , Sheinman I. 
Published: June 2007

AbstractThe buckling of axially‐loaded, imperfect, circular, cylindrical, thin shells is studied. A solution methodology, based on two different shell theory approximations to the kinematic relations, is developed and described. The two approximations are those of Sanders and Donnell. Critical loads (limit point loads) are obtained for two shell geometries, one isotropic and one laminated. Several parametric studies are performed in order to establish the accuracy of the Donnell approximation. This is accomplished by comparison to the results obtained by the Sanders kinematic relations, which are considered to be very accurate for thin shells. The parametric studies include the effect of cylinder to radius ration on the critical loads, as well as the effect of the radius to thickness ratio. Moreover, the imperfection sensitivity of the two geometries is investigated by both shell theory approximations.
Inequalities for the Eigenvalues of a Non‐Negative Definite Matrix and a Generalization
Authors: Goller H. , Krafft O. 
Published: June 2007

AbstractIn the first part it is shown that some known inequalities for eigenvalues, e.g. for eigenvalues of sums or products of non‐negative definite matrices, easily follow from a variant of the Courant‐Fischer minimax theorem. This variant establishes a relation between the k‐th of the ordered eigenvalues and a matrix of rank k. Furthermore, the problem of determining extremal ellipsoids which are centered at a point d ≠ 0 and which are tangential at the unit sphere is discussed as a generalized eigenvalue problem.
Das Stabilitätsverhalten der verallgemeinerten Mathieuschen, Kohnschen und Weigandschen Differentialgleichung
Authors: Eicher N. 
Published: June 2007

AbstractFür eine Klasse von zeitvarianten Schwingungssystemen wird das Stabilitätsverhalten untersucht. Aufgrund einer geeigneten Berechnungsmethode lassen sich allgemeingültige Bereichsgrenzenformeln für alle Parameterresonanzen herleiten. Eine anschließende Diskussion des Stabilitätsverhaltens der zu dieser Klasse gehörenden Schwingungsgleichungen ergibt wesentliche Unterschiede. Für harmonische Erregungen werden Stabilitätskarten angegeben und beurteilt. Es wird auf die bekannten Transformationen, welche die Differentialgleichungen innerhalb der Klasse ineinander überführen, eingegangen und deren Grenzen aufgezeigt.
Analystische Berechung der Drehschwingungen mehrstufiger Stirnradgetriebe
Authors: Schulz R. 
Published: June 2007

AbstractFür ein N‐stufiges Stirnradgetriebe mit Übersetzungsverhältnissen der einzelnen Stufen, die wesentliche von 1 verschieden sind, werden explizite Näherungsformeln für die Stabilitätsgrenzen und die dynamischen Zusatzbelastungen, die durch die Zahnsteifeerregung hervorgerufen werden, abgeleitet. Es werden dabei die Störungstheorie endlichdimensionaler Operatoren und das Integralgleichungsverfahren verwendet.
Zur Anisotropie deformierbarer Körper bei großen Verformungen
Authors: Balke H. 
Published: June 2007

AbstractDer Anisotropiebegriff für mechanische Eigenschaften deformierbarer Körper bei großen Verformungen wird diskutiert. Grundlage der Diskussion ist die genaue Abgrenzung von Objektivitäts‐ und Symmetrieforderungen an die konstitutiven Gleichungen. Als Beispiele werden Potentiale der Fließ‐ oder Kriechtheorie in raumfesten und mitgeführten Koordinaten, Kriechgleichungen und hypoelastisches Material betrachtet. Dabei wird auf existierende Inkonsequenzen in der Literatur eingegangen.
Stopping Check for Systems with Friction‐Affected Constraints
Authors: Klepp H. J. 
Published: June 2007

AbstractA multi‐body system with several degrees of freedom and friction‐affected constraints (guidances and journal bearings) is considered. It is supposed that the original system and all systems, which must be considered as result of sticking coordinates, are kineto‐statically determinate structures. It is also assumed that the relative velocities in the constraints depend respectively on one of the generalized coordinates and its derivative. A criterion is presented, which establishes the state of the system, when relative movements in some constraints with friction stop simultaneously. As an example a system with four degrees of freedom and seven friction‐affected constraints is considered.
Small‐Scale Extrusion of Corn Masa By‐Products
Authors: Rosentrater K. A. , Richard T. L. , Bern C. J. , Flores R. A. 
Published: June 2007

ABSTRACTCorn masa by‐product streams are high in fiber and are amenable for utilization in livestock feed rations. This approach is a potentially viable alternative to landfilling, the traditional disposal method for these processing residues. Suspended solids were separated from a masa processing waste stream, blended with soybean meal at four levels (0, 10, 20, and 30% wb), and extruded in a laboratory‐scale extruder at speeds of 50 rpm (5.24 rad/sec) and 100 rpm (10.47 rad/sec) with temperature profiles of 80‐90‐100°C and 100‐110‐120°C. Processing conditions, including dough and die temperatures, drive torque, specific mechanical energy consumption, product and feed material throughput rates, dough apparent viscosity, and dough density, were monitored during extrusion. The resulting products were subjected to physical and nutritional characterization to determine the effects of processing conditions for these blends. Extrudate analysis included moisture content, water activity, crude protein, in vitro protein digestibility, crude fat, ash, product diameter, expansion ratios, unit and true density, color, water absorption and solubility, and durability. All blends were suitable for extrusion at the processing conditions used. Blend ratio had little effect on either processing parameters or extrudate properties; extrusion temperature and screw speed, on the other hand, significantly affected both processing and product properties.
Application of Response Surface Methodology in the Development of Gluten‐Free Bread
Authors: McCarthy D. F. , Gallagher E. , Gormley T. R. , Schober T. J. , Arendt E. K. 
Published: June 2007

ABSTRACTThe formulation of gluten‐free (GF) bread of high quality presents a formidable challenge as it is the gluten fraction of flour that is responsible for an extensible dough with good gas‐holding properties and baked bread with good crumb structure. As the use of wheat starch in GF formulations remains a controversial issue, naturally GF ingredients were utilized in this study. Response surface methodology was used to optimize a GF bread formulation primarily based on rice flour, potato starch, and skim milk powder. Hydroxypropylmethylcellulose (HPMC) and water were the predictor variables. Analyses of the treatments from the design were made 24 hr after baking. Specific volume and loaf height increased as water addition increased (P < 0.01). Crumb firmness decreased as water levels increased (P < 0.01). Significant interactions (P < 0.01) between HPMC and water were found for the number of cells/cm2. The number of large cells (>4 mm2) decreased with increasing levels of HPMC and water. Optimal ingredient levels were determined from the data obtained. The optimized formulation contained 2.2% HPMC and 79% water flour/starch base (fsb) and measured responses compared favorably to predicted values. Shelf‐life analysis of the optimized formulation over seven days revealed that, as crumb firmness increased, crust firmness and crumb moisture decreased.
Milling Quality and White Salt Noodle Color of Chinese Winter Wheat Cultivars
Authors: Zhang Yan , Quail K. , Mugford D. C. , He Zhonghu 
Published: June 2007

ABSTRACTImprovement of milling quality is an important aspect in wheat breeding programs. However, the milling quality of Chinese wheats remains largely unexplored. Fifty‐seven Chinese winter wheat cultivars from four regions were used to investigate the variation of milling quality parameters and to determine the associations between milling quality traits and color of noodle sheet. Substantial variation was presented for all measured parameters in this germplasm pool. Complete soft, hard, and medium‐hard types were observed. Soft wheat and hard wheat show significant differences in flour ash content, flour bran area, and flour color grade. No simple trait can be used to select for flour milling quality. High flour ash content and bran speck area contributed negatively to brightness of dry flour. Correlation coefficients (r) between L* value of dry flour and flour ash content and bran speck area were ‐0.47 and ‐0.65 for hard cultivars, and ‐0.51 and ‐0.72 for soft cultivars, respectively. Flour color grade (FCG) was significantly and positively associated with bran speck area; r = 0.56 and 0.73 for hard and soft wheats, respectively. There was a high correlation between FCG and L* value of flour water slurry (r = ‐0.95). Strong associations were also established between milling quality index (MQI) and FCG, L* value of dry flour, flour‐water slurry, and white salted noodle sheet for both hard and soft wheats. In conclusion, substantial progress could be achieved in improvement of milling quality in Chinese winter wheats through genetic selection, and FCG and MQI could be two important parameters for evaluation of milling quality in breeding programs.
Effect of Starch Granule Size Distribution and Elevated Amylose Content on Durum Dough Rheology and Spaghetti Cooking Quality
Authors: Soh H. N. , Sissons M. J. , Turner M. A. 
Published: June 2007

ABSTRACTTo obtain an indication of the effect of increasing the starch amylose content above normal levels (27–74%) and increasing the percentage of B‐type starch granules (11–60%) on durum dough properties and the quality of the spaghetti derived from these doughs, the reconstitution approach was used. Reconstituted flours were prepared from a common Wollaroi gluten, solubles and tailings fraction combined with starches containing varying B‐granule contents, or with starches from maize with varying amylose content. An increased B‐granule content increased farinograph water absorption. Cooked spaghetti firmness was highest with B‐type granules at 32–44% (volume percentage basis), which is ≈10–15% higher than normally found in durum starch. Increasing the amylose content in the starch caused the dough to be more extensible, increased spaghetti firmness, and decreased water absorption with optimum quality of amylose at 32–44%. The information indicates there would be benefit in producing durum wheats with slightly elevated B‐granule and amylose contents.
Granule Bound Starch Synthase I (GBSSI) Gene Effects Related to Soft Wheat Flour/Starch Characteristics and Properties
Authors: Geera B. P. , Nelson J. E. , Souza E. , Huber K. C. 
Published: June 2007

ABSTRACTEight soft spring wheat (Triticum aestivum L.) genotypes representing the four granule bound starch synthase I (GBSSI) classes were evaluated with respect to flour/starch characteristics and pasting behaviors. Native starch was isolated from genotype straight‐grade flours (94.8–98.1% of starch recovered) to approximate the starch populations of the parent flours. As anticipated, amylose characteristics varied among the genotypes according to GBSSI class and accounted for the primary compositional difference between genotypes. Total (TAM), apparent (AAM), and lipid‐complexed (LAM) amylose contents ranged from 1.0–25.5 g, 0.7–20.4 g, and 0.3–5.6 g/100 g of native starch, respectively, and gradually decreased with the progressive loss of active Wx alleles. In addition, genotype flour total starch (FTS) and A‐type starch granule contents, which ranged from 81.7–87.6 g/100 g of flour (db) and 61.6–76.8 g/100 g of native starch (db), respectively, generally decreased with an increase in waxy character in parallel with amylose characteristics, as likely secondary effects of Wx gene dosage. Though amylose characteristics predominantly accounted for the majority of genotype flour pasting properties, FTS content and ratios of A‐ to B‐type granules also exhibited significant influence. Thus, loss of one or more Wx genes appeared to induce measurable secondary effects on starch characteristics and properties.
Flour Pasting Properties of Wild‐Type and Partial Waxy Soft Wheats in Relation to Growing Environment‐Induced Fluctuations in Starch Characteristics
Authors: Geera B. P. , Nelson J. E. , Souza E. , Huber K. C. 
Published: June 2007

ABSTRACTTo relate growing environment‐induced differences in wheat (Triticum aestivum L.) flour pasting properties with fluctuations in starch characteristics, starch characteristics of flours milled from wild‐type and partial waxy wheat genotypes grown at two diverse locations (irrigated vs. rainfed) over two successive crop years (2000, 2001) were analyzed. The crop year or growing location that possessed the highest peak and breakdown viscosity values exhibited the highest mean flour total starch (FTS) content, while that exhibiting the highest trough, final, and setback viscosities possessed the highest mean A‐type granule content. Correlation analysis across growing environments provided additional evidence for associations between flour pasting properties and flour/starch characteristics. Fluctuations in mean FTS content were associated with flour peak (r = 0.95) and breakdown (r = 0.93) viscosity differences, while variability in A‐type granule content was strongly correlated with fluctuations in trough (r = 0.82), final (r = 0.96), and setback (r = 0.99) viscosities. Peak viscosity was also negatively correlated with total (r = ‐0.78) and lipid‐complexed (r = ‐0.72) amylose contents. Of the flour/starch characteristics measured, variability in FTS and A/B‐type granule contents best explained growing environment‐induced fluctuations in flour pasting properties.