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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 1 (1955), S. 410-412 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 95-103 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Measurements were taken of the viscoelastic properties of six polymer melts by mean of the Weissenberg rheogoniometer and the Han slit/capillary rheometer. Polymers in vestigated were three high-density polyethylenes of different polydispersity, a low-density polyethylene, a polypropylene, and a polystyrene. The range of shear rates tested was from about 5.0 × 10-3 to 10 sec-1 with the Weissenberg rheogoniometer, from about 10 to 102 sec-1 with the slit rheometer, and from about 102 and 103 with the capillary rheometer: the temperature of measurement was 200°C. The three different apparatuses give consistent results over almost six decades of shear rates, yielding satisfactory correlations of shear viscosity to shear rate and of normal stress difference to shear rate.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 35 (1992), S. 409-424 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Accurate natural frequencies of skewed cantilevered thin plates are determined using the Ritz method. The present work is the first known vibrational study of the effects of stress singularities at the reentrant corner of skewed plates. In conjunction with classical thin plate theory, the Ritz trial space of assumed transverse displacement functions consists of algebraic polynomials, which are mathematically complete, and corner functions, which account for the singular behaviour of bending stresses at the reentrant corner. The corner functions were derived approximately four decades ago to study the nature of the stress singularities which occur at sharp interior corners or crack tips of typical plane elasticity and plate bending problems. Accurate non-dimensional frequencies are calculated for thin plates having various side ratios and arbitrary degrees of skewness. Detailed numerical studies show that augmenting the Ritz trial space of polynomials with corner functions, having a co-ordinate origin at the reentrant corner, enhances the convergence of the upper-bound frequencies. The importance of using corner functions in skew plate vibrations is found to increase as the skew angle increases and as the side ratio decreases. Results obtained using the present method are compared with those obtained by other investigators using both theoretical and experimental methods.
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 39 (1996), S. 605-618 
    ISSN: 0029-5981
    Keywords: inverse heat conduction problem ; heat capacity determination ; non-linear problem ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An inverse analysis utilizing the conjugate gradient method and the minimization of adjoint equation is used successfully to estimate the temperature dependent heat capacity per unit volume in a homogeneous medium.No prior information is available on the functional form of the unknown heat capacity in the present study, thus, it is classified as the function estimation in inverse calculation. The accuracy of the inverse analysis is examined by using simulated exact and inexact measurements obtained within the medium. Results show that an excellent estimation on the heat capacity per unit volume can be obtained by using just boundary measurements (i.e. internal measurements are unnecessary) and the CPU time used in VAX-9420 computer is less than one second.The advantages of applying this algorithm in inverse analysis can greatly simplify the experimental set-up, diminish the sensitivity to the measurement errors and reduce the CPU time in inverse calculation, while the reliable predictions can still be achieved.
    Additional Material: 7 Ill.
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  • 5
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Um ein „härtbares“ Harz zu erhalten, das nur aus Kohlenstoff und Wasserstoff besteht, wurde ein Xylol-Formaldehyd-Harz (XF-Harz) mit einem Kohlenwasserstoff (CH) wie folgt umgesetzt: Es wurde dabei angenommen, daß hierbei eine elektrophile Substitution erfolgt. Auf der Suche nach reaktionsfähigen Kohlenwasserstoffen wurden 15 verschiedene aromatische Verbindungen in Gegenwart von Perchlorsäure mit Formaldehyd umgesetzt. Dabei reagierten Acenaphthen, Polyacenaphthylen, Anthracen und Mesitylen leicht mit Formaldehyd. Es wurden nunmehr XF-Harze hergestellt und mit den erwähnten aromatischen Kohlenwasserstoffen umgesetzt. Dabei waren Acenaphthen, Polyacenaphthylen und Acenaphthen-Formaldehydharz besonders wirksam.Da ein ω,ω'-Dimethylol-XF-Harz bei der Umsetzung noch wirksamer als ein normales Harz sein sollte, wurde eine brauchbare Methode für die Herstellung eines ω,ω'-Dimethylol-XF-Harzes entwickelt. Durch Umsetzung des ω,ω'-Dimethylol-XF-Harzes mit Acenaphthen-Formaldehyd-Harz in Gegenwart von Xylolsulfonsäure wurde schließlich ein gezielt vernetztes Harz erhalten, das nur aus Kohlenstoff und Wasserstoff bestand. Es ist unschmelzbar und in Benzol unlöslich.(Unter geänderten Bedingungen kann auch Anthracen oder Mesitylen das XF-Harz vernetzen).
    Notes: A study to obtain a resin consisting only of carbon and hydrogen and yet having thermosetting properties was made. The process was a reaction of xylene-formaldehyde resin (XF-resin) with a hydrocarbon (CH) The reaction was assumed to proceed through an electrophilic substitution. To find some reactive hydrocarbons, 15 different aromatic hydrocarbons have been reacted with formaldehyde in the presence of perchloric acid. It was found that acenaphthene, acenaphthylene, anthracene and mesitylene easily reacted with formaldehyde. Some XF-resins were prepared, and reacted with the mentioned aromatic hydrocarbons.Of these hydrocarbons, acenaphthene, polyacenaphthylene and acenaphthene-formaldehyde resin were especially effective.It is understandable that an ω,ω'-dimethylol-XF-resin is more effective than a normal XF-resin. So an useful method for the synthesis of the ω,ω'-dimethylol-XF-resin was investigated.By the reaction of ω,ω'-dimethylol-XF-resin with acenaphthene-formaldehyde resin in the presence of xylene sulfonic acid, the desired cured resin was obtained. The resin consisted only of carbon and hydrogen. It was insoluble in benzene and non-melting. (However, by changing the conditions, anthracene or mesitylene can also cure XF-resins).
    Additional Material: 32 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 357-366 
    ISSN: 0887-624X
    Keywords: surface graft copolymerization ; adhesive-free adhesion ; polycarbonate ; XPS ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The surfaces of ozone-pretreated polycarbonate films were subjected to further modification by thermally induced graft copolymerization with acrylic acid (AAc), sodium salt of styrene sulfonic acid (NaSS), N,N-dimethylacrylamide (DMAA), N,N-(dimethylamino)ethyl methacrylate (DMAEMA) and 3-dimethyl(methacryloyl ethyl)-ammonium propanesulfonate (DMAPS) monomers. The structure and composition at the copolymer interface were studied by angle-resolved X-ray photoelectron spectroscopy (XPS). For polycarbonate films with a substantial amount of grafted polymer, the hydrophilic graft penetrates or becomes partially submerged beneath a thin surface layer of dense substrate chains. This microstructure was further supported by the water contact angle measurements. Adhesive-free adhesion studies revealed that the AAc, DMAA or DMAPS graft copolymerized polycarbonate film surface adhered strongly to another similarly modified surface (homo-interface) when brought into direct contact in the presence of water and subsequently dried. The development of the lap shear strength is dependent on the concentration of the surface graft, the microstructure of the grafted surface, the adhesion (drying) time, and the nature of the interfacial interaction. The simultaneous presence of chain entanglement and electrostatic interaction readily results in substantially enhanced adhesion strengths between two DMAPS graft copolymerized surfaces or between an AAc and a DMAA graft copolymerized surface (hetero-interface). XPS analyses of the delaminated surfaces suggest that failure occurred cohesively below the graft-substrate interface. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 357-366, 1998
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 13 (1997), S. 103-112 
    ISSN: 1069-8299
    Keywords: static reanalysis ; finite element method ; structural analysis ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper presents an exact structural static reanalysis method for locally modified structures. Through the introduction of structural rigid body motion eigenvectors, the generalized structural compliance matrix can be obtained and the original stiffness equation is transformed into a linear system of much lower order. The general solution of displacements can be expressed prior to any assignment of boundary conditions. For a structure with given boundary and loading conditions, the displacements can be obtained by solving this linear system. For locally modified structures, the structural compliance matrix can be adjusted quickly. This static reanalysis method can be used for structures with modifications on structural elements, boundary and loading conditions, either independently or in combination. Two test examples are provided in the paper to prove the efficiency of the method. © 1997 John Wiley & Sons, Ltd.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 577-584 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A study of rat-tail tendon fibers, about 200 μ in diameter, by scanning electron microscopy of fractured specimens reveals that these crimped fibers are largely made up of cylindrical units, about 10 μ in diameter. These, in turn, are made up of the well-known collagen fibrils, ca. 0.1 μ in diameter, which have been observed previously by transmission electron microscopy and small-angle x-ray diffraction. Both the 10-μ and 0.1-μ cylindrical units were found to be arranged parallel to the macroscopic fiber axis rather than helically about it, as has been often proposed in the past. Significant improvement in resolution of the fracture surfaces was obtained by dehydration of the tendon. Microscopy of undehydrated tendon fibers undergoing solubilization by dilute aqueous acetic acid confirmed the results obtained by fractography.
    Additional Material: 8 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 223-230 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The transport equations for a power law fluid are used to solve the transient and non-isothermal problem of filling a disk-shaped cavity. Using the results obtained it is possible to predict gate pressures, fill times and short shots. Furthermore, the velocity and temperature fields can be obtained throughout the filling process. This information specifies the formation of a frozen surface layer during filling. Rigid PVC was primarily used in the simulations, but some results are also given for linear polyethylene, nylon 6-6, ABS and polystyrene.
    Additional Material: 13 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 910-922 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The five independent elastic moduli C11, C12, C13, C33, and C44 for uniaxially drawn polyoxymethylene with draw ratio λ = 1-16 have been measured from -60 to 120°C by an ultrasonic method at 10 MHz. Wide angle x-ray diffraction and birefringence measurements indicate that the chains in the crystalline regions are fully aligned at λ = 5 but the degree of amorphous orientation increases steadily up to the highest draw ratio. Below the major amorphous γ relaxation (∼0°C at 10 MHz), only the axial longitudinal and tensile modulus, C33 and E0, show large increases. At 120°C, however, all the moduli increase with λ, with E0, E90 (transverse tensile modulus), C44 (axial shear modulus) and C66 (transverse shear modulus) increasing 10, 2.5, 3, and 2.5 times, respectively, as λ rises from 1 to 16. This improvement in mechanical properties may be attributed largely to the effect of taut tie-molecules and crystalline bridges. Whereas the two-parameter model of Seferis seems to be valid only below the γ relaxation, the Halpin-Tsai equation can give a reasonable description of the mechanical behavior for the highly oriented samples (λ〉5) over the entire temperature range.
    Additional Material: 21 Ill.
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