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  • 1
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    Vortical sources of aerodynamic force and moment (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: It is shown that the aerodynamic force and moment can be expressed in terms of vorticity distribution (and entropy variation for compressible flow) on near wake plane, or in terms of boundary vorticity flux on the body surface. Thus the vortical sources of lift and drag are clearly identified, which is the real physical basis of optimal aerodynamic design. Moreover, these sources are highly compact, hence allowing one to concentrate on key local regions of the configuration, which have dominating effect to the lift and drag. A detail knowledge of the vortical low requires measuring or calculating the vorticity and dilatation field, which is however still a challenging task. Nevertheless, this type of formulation has some unique advantages; and how to set up a well-posed problem, in particular how to establish vorticity-dilatation boundary conditions, is addressed.
    Keywords: AERODYNAMICS
    Type: SAE PAPER 892346
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Streaming effect of wall oscillation to boundary layer separation (1991)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: This paper presents a preliminary theoretical result on the time averaged streaming effect of local forcing excitation to the boundary layer separation from smooth surface. The problem is formulated as a periodic disturbance to a basic steady breakaway separating flow, for which the data are taken from a numerical triple-deck solution. The ratio of Strouhal number St and Reynolds number Re plays an important role, both being assumed sufficiently high. The analytical and numerical results show that this streaming effect is quite strong at proper values of St/Re exp 1/4, which may delay or even suppress the separation.
    Keywords: AERODYNAMICS
    Type: AIAA PAPER 91-0545
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    Review of the physics of enhancing vortex lift by unsteady excitation (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: A review aimed at providing a physical understanding of the crucial mechanisms for obtaining super lift by means of unsteady excitations is presented. Particular attention is given to physical problems, including rolled-up vortex layer instability and receptivity, wave-vortex interaction and resonance, nonlinear streaming, instability of vortices behind bluff bodies and their shedding, and vortex breakdown. A general theoretical framework suitable for handling the unsteady vortex flows is introduced. It is suggested that wings with swept and sharp leading edges, equipped with devices for unsteady excitations, could yield the first breakthrough of the unsteady separation barrier and provide super lift at post-stall angle of attack.
    Keywords: AERODYNAMICS
    Type: Progress in Aerospace Sciences (ISSN 0376-0421); 28; 2 19
    Format: text
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  • 4
    Electronic Resource
    Electronic Resource
    Stability of chemical sequence in a periodic polymeric nematogen (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 285-293 
    Details
    ISSN: 0887-624X
    Keywords: liquid crystal polymers ; transesterification ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stability of a polymeric nematogen's chemical sequence was studied by differential scanning calorimetry, optical microscopy, and 13C-NMR; the nematogen studied was a thermotropic polyester and had a periodic chemical structure. Model compounds were used to investigate transesterfication in the melt at different temperatures with the addition of phenol or benzoic acid as analogues of polymer end groups. Ester interchange reactions at high temperature were found to be partly suppressed when acidic end groups of the periodic nematogen were capped. However, sequence reorganization was completely suppressed in capped nematogens when temperatures remained below the isotropization transition of the nematogen investigated. Rapid disordering of the periodic nematogen was observed above the nematic-isotropic transition, suggesting that both chemical and physical factors play a role in sequence redistribution of periodic nematogens. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080320209
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  • 5
    Electronic Resource
    Electronic Resource
    Assessment of virus production and chloramphenicol acetyl transferase expression by insect cells in serum-free and serum-supplemented media using a temperature-sensitive baculovirus (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 38 (1991), S. 1091-1099 
    Details
    ISSN: 0006-3592
    Keywords: chloramphenicol acetyl transferase ; baculovirus ; Spodoptera frugiperda ; serum-free medium ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Spodoptera frugiperda insect cells were grown in Sf-900 serum-free medium and two kinds of serum-supplemented media (IPL -41 and Grace's). The specific growth rates of uninfected cells were found to be 0.024, 0.35, and 0.034 h-1 respectively, at 33°C. The IPL -41 medium supported to highest maximum cell density (10.6 × 106 cells/mL) compared to 3.5 × 106 and 8.7 × 106 cells/mL with the Grace's and serum-free media, respectively. In temperature shifdown experiments with a temperature-sensitive baculo-virus (acts10YM1CAT), virus titer and chloramphenicol acetyl transferase (CAT) expression were highest in the IPL -41 (5.1 × 107 PFU/mL and 20000 U/mL). Use of Grace's medium gave higher virus titers than the serum-free medium (4.4 × 106 vs 4.1 × 105 PFU/mL) as well as higher CAT titers (7050 vs 1980 U/mL). Interestingly, in the three media used, the highest virus and CAT titers were obtained at MOI (multiplicity of infection) of 0.02 At MOI of 2.0 virtually no increase in virus of CAT titer was observed. This result is contrary to those obtained at constant-temperature (27°C) infection and cell culture, in which higher virus titers and recombinant protein expression and obtained at higher MOI.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260380918
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  • 6
    Electronic Resource
    Electronic Resource
    Copper bilirubinate and black pigment gallstone (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 1 (1995), S. 149-156 
    Details
    ISSN: 1075-4261
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A series of copper bilirubinate complexes (CuBR) was synthesized in solution and in solid state to mimic the black color of the black-pigment gallstone and to explore the formation mechanism of the gallstonein vitro. The variation of the copper contents of these samples indicated that CuBR also exhibits nonstoichiometric characteristics from the FTIR study, i.e., both the so-called acid and neutral copper complex moieties exist in CuBR. The NH groups in pyrrole and lactam groups of bilirubin (H2BR) are binding to the copper ions. An EPR study demonstrates the generation of free radicals and the variation of its electronic structure and conjugation system in the skeleton of H2BR molecule during complex formation. A polymer of CuBR may form through the reaction of H2BR with copper ions. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bspy.350010209
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  • 7
    Electronic Resource
    Electronic Resource
    A spectroscopic study of pigment gallstones in China (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Biospectroscopy 3 (1997), S. 371-380 
    Details
    ISSN: 1075-4261
    Keywords: brown pigment stone ; PAGE ; mid-IR spectroscopy ; far IR spectroscopy ; FT-Raman ; bezoar ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Spectroscopic studies of various types of gallstones carried out in China are reviewed. Three basic classes of gallstones are surveyed: cholesterol stones, brown pigment stones, and black pigment stones. The emphasis of this review is on brown gallstones. The primary spectroscopic methods used in the studies surveyed are Fourier transform infrared absorption and Fourier transform Raman scattering. Chemical components studied in gallstones include cholesterol, bile pigments, glycoproteins, proteins, bilirubin metal complexes, and salts of calcium and other metals. Further studies are needed characterize the relationship of these components to more complex features of gallstones. © 1997 John Wiley & Sons, Inc. Biospectroscopy 3: 371-380, 1997
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Solution properties of ionomers. I. Counterion effect (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 1407-1418 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of counterions on the solution properties of two types of ionomers, one based on sulfonated polystyrene and the other based on styrene-methacrylic acid copolymer, was studied by viscosity and light scattering measurements. It was found that the order of counterion binding of ionomers in a polar solvent and the order of aggregation of ionomers in a low-polarity solvent were the same for the same ionomer system. However, the order for the sulfonated ionomer was Li 〈 Na 〈 K 〈 Cs, whereas that for the carboxylated ionomer was the opposite. This can be explained by a difference in desolvation during anion-cation interaction and by considering site-binding in a polar solvent and the association of ion pairs in a low-polarity solvent. These findings for ionomer systems are parallel to the association behavior of small ions in water, cation affinity in crosslinked resins, and counterion binding of polyelectrolytes in water.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1987.090250704
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  • 9
    Electronic Resource
    Electronic Resource
    Numerical simulation of anomalous penetrant diffusion in polymers (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1845-1856 
    Details
    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: This work introduces a new numerical algorithm that can be used to analyze complex problems of penetrant transport. Penetrant transport in polymers often deviates from the predictions of Fick's law because of the coupling between penetrant diffusion and the polymer mechanical behavior. This phenomenon is particularly important in glassy polymers. This leads to a model consisting of two coupled differential equations for penetrant diffusion and polymer stress relaxation, respectively. If the polymer relaxation is the rate-limiting step, both the concentration and stress profiles are very steep. A new algorithm based on a finite difference method is proposed to solve the model equations. It features the development of a tridiagonal iterative method to solve the nonlinear finite difference equations obtained from the finite difference approximation of the differential equations. This method was found to be efficient and accurate. Numerical simulation of penetrant diffusion in glassy polymers was performed, showing that the integral sorption Deborah number is a major parameter affecting the transition from Fickian to anomalous diffusion behavior. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070491015
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  • 10
    Electronic Resource
    Electronic Resource
    Modeling of penetrant diffusion in glassy polymers with an integral sorption deborah number (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 31 (1993), S. 1503-1518 
    Details
    ISSN: 0887-6266
    Keywords: anomalous transport ; glassy polymers ; diffusion ; Deborah number ; Case II transport ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A mathematical model was developed to explain the anomalous penetrant diffusion behavior in glassy polymers. The model equations were derived by using the linear irreversible thermodynamics theory and the kinematic relations in continuum mechanics, showing the coupling between the polymer mechanical behavior and penetrant transport. The Maxwell model was used as the stress-strain constitutive equation, from which the polymer relaxation time was defined. An integral sorption Deborah number was proposed as the ratio of the characteristic relaxation time in the glassy region to the characteristic diffusion time in the swollen region. With this definition, an integral sorption process was characterized by a single Deborah number and the controlling mechanism was identified in terms of the value of the Deborah number. The model equations were two coupled nonlinear differential equations. A finite difference method was developed for solving the model equations. Numerical simulation of integral sorption of penetrants in glassy polymers was performed. The simulation results show that (1) the present model can predict Case II transport behavior as well as the transition from Case II to Fickian diffusion and (2) the integral sorption Deborah number is a major parameter affecting the transition. © 1993 John Wiley & Sons, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1993.090311108
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