Rigid-bond test

TABLE 2.3 Rigid-Bond Test for p-Nitropyridine-N-oxide at 30 K... 

The use of more sophisticated scattering models, in which bonding effects on the charge density are taken into account, discussed in chapter 3, leads to a significant improvement in the results of the rigid-bond test. An example, based on a low-temperature analysis of p-nitropyridine-N-oxide, is given in Table 2.3. 

The introduction of standard aspherical-atom scattering factors leads to a very significant improvement in Hirshfeld s rigid bond test. The results are a beautiful confirmation of Hirshfeld s (1992) statement that an accurate set of nuclear coordinates (and thermal parameters ) and a detailed map of the electron density can be obtained, via X-ray diffraction, only jointly and simultaneously, never separately or independently . 

Some criteria have been suggested in order to decide when a thermal motion analysis can be expected to yield meaningful results. Two of them, the rigid-bond test and the rigid-molecule test, investigate whether or not bonds or portions of molecules are considered to move in a physically reasonable way. They will be described in turn. 

Muller et al. focused on polybead molecules in the united atom approximation as a test system these are chains formed by spherical methylene beads connected by rigid bonds of length 1.53 A. The angle between successive bonds of a chain is also fixed at 112°. The torsion angles around the chain backbone are restricted to three rotational isomeric states, the trans (t) and gauche states (g+ and g ). The three-fold torsional potential energy function introduced [142] in a study of butane was used to calculate the RIS correlation matrix. Second order interactions , reflected in the so-called pentane effect, which almost excludes the consecutive combination of g+g- states (and vice-versa) are taken into account. In analogy to the polyethylene molecule, a standard RIS-model [143] was used to account for the pentane effect. 

Rosenfield, R. E., Trueblood, K. N., and Dunitz, J. D. (1978). A test for rigid-body vibrations based on a generalization of Hirschfeld s rigid-bond postulate. Acta Cryst. A34, 828-9. 

De Hoff PH, Anusavice KJ, Wang Z (1995) Three-dimensional finite element analysis of the shear bond test. Dent Mater 11(2) 126-131 Lee CH, Kobayashi S (1973) New solution to rigid-plastic deformation problems using matrix methods. Trans ASME J Eng Ind 95(3) 865-873 Lewis RW, Ravindran K (2000) Finite element simulation of metal casting. Int J Numer Methods Eng 47(l-3) 29-59 (Special Issue Richard H. Gallagher Memorial Issue)... 

EN 28510 1993 Adhesives - Peel test for a flexible to rigid bonded assembly, Part 1 90° peel, Part 2 180° peel... 

Adhesives determination of tensile lap-shear strength of rigid-to-rigid bonded assemblies Adhesives diuabUity of stmctural adhesive joints exposure to humidity and temperature under load Adhesives test methods for fatigue properties of stmctural adhesives in tensile shear... 

PVDF film is readily commercially available in thicknesses up to 110 pm. If film of this thickness is bonded to a rigid substrate, the peak response is at a frequency of about 3.7 MHz which corresponds to the thickness of the layer being a quarter wavelength. This frequency is rather high for most Lamb wave testing since Fig 1 shows that even on a I mm thick... 

Subsequent to processing, an inspection is made for incomplete bonding, inside dirt, and glass quaUty. In the case of windshields, rigid optical standards must be met, and these must be evaluated for the completed windshield. Extensive test requirements are described in the appropriate codes (11,12,15,18—24), and they include light stabiUty, resistance to optical distortion, humidity, boil test, abrasion resistance, and assorted impact tests. 

ISO 11003-1 2001 Adhesives - Determination of shear behaviour of structural adhesives -Part 1 Torsion test method using butt-bonded hollow cylinders ISO 11003-2 2001 Adhesives - Determination of shear behaviour of structural adhesives -Part 2 Tensile test method using thick adherents ISO 13445 2003 Adhesives - Determination of shear strength of adhesive bonds between rigid substrates by the block-shear method... 

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