1- AVERAGE LATENESS ( NEW ) ( PERFORMANCE MEASUREMENT )
( Oyetunji E.O. Some Common Performance Measures in Scheduling Problems: Review Article, pg.7 )
THERE IS NOT OLDER VERSION !!!
2- NEUTRON DIFFRACTION ( NEW ) ( BETTER ) ( MOLECULAR-PHYSICS )
According to the wave-particle dualism (λ = h/mv, de Broglie) neutrons have wave properties
As X-rays neutrons have a wavelength on the order of the atomic scale (Å) and a similar interaction strength with matter (penetration depth from μm to many cm)
Neutrons generate interference patterns and can be used for Bragg diffraction experiments
Same scattering theory for neutrons and X-rays
Fission process: 1 MeV – too high for practical use Neutrons are slowed down (moderated in water or carbon)
hot neutrons:
moderated at 2000°C
0.1-0.5 eV, 0.3-1 Å, 10 000 m/s
thermal neutrons:
moderated at 40°C
0.01-0.1 eV, 1-4 Å, 2000 m/s
cold neutrons:
moderated at -250°C
0-0.01 eV, 0-30 Å, 200 m/s
Neutron diffraction is a non-routine complementary technique allowing detection of light elements, recording of higher intensity Bragg reflections at high angle, discrimination of neighbouring elements
( Behrens Malte, Powder X-Ray and Neutron Diffraction ,pg. 32, 36, 42 )
Neutron Diffraction ( OLD )
Neutron Diffraction (ND) is capable of measuring the elastic strains induced by residual stresses throughout the colume of relatively thick stess components with a spatial resolution as small as 1 mm^3. Such capabilities provide for residuals-tress measurement inside components without sectioning or layer removal. Principal ND methos, as with XRD methods, measure the spacing between crystallographic planes in a component, and this spacing is affected by residual and applied stress. The spacing between a selected set of a crystallographic planes is related to the angle of incidence and diffraction of where teh neutron radiation, which are equal, and the wavelength of the monochromaric radiation by Bragg's Law: λ= 2 d sin θ
The elastic strain induced bt the residual stress perpendicular to teh diffracting crystallographic plane then is related to d by:
ε= (d-d0)/do= sinθ0(sinθ-sinθ0)
(Totten, G., Howes, M., Inoue, T., Handbook of Resifual Stress and Deformation, 1st Printing, March 2002, pg.113)
3- OBLIQUITY ANGLE ( NEW ) ( BETTER ) ( PHYSICAL PARAMETERS )
The obliquity angle corresponds to an angular remodeling of the femoral diaphysis, which is independant of the growth and shape of the distal femoral epiphysis. The tibio-femoral angle measures the evolution of a physiologic phenomenon, from the load “in varus” to the load “in valgus” of the lower limb. It is linked with the bicondylar angle but is different from it.
( Tardieu C. and Damsin J. P. Evolution of the angle of obliquity of the femoral diaphysis during growth, Abstract )
Obliquity Angle: ( OLD )
Angle of Obliquity: Angle between vehicle body axis and target normal at point of impact (positive is clockwise).
Concepts to Alternatives, Cabasso J., p.4
4- APPROACH ANGLE ( NEW ) ( BETTER ) ( CAR INDUSTRY )
the approach angle is the smallest angle, in the side view of a vehicle, formed by the level surface on which the vehicle is standing and a line tangent to the front tyre "Static Loaded Tyre Radius" arc and touching the underside of the vehicle forward of the front tyre
( USA Government Press ,CUSTOMS TARIFF SCHEDULE 3, Section 17 Chapter 18/2 )
Approach Angle ( OLD )
Side cutting edge angle is angle between the side cutting edge and the longitudinal axis of tool. Its complimentary angle is approach angle, which is between feed direction and side cutting edge.
(Manufacturing Processes Second Edition, J.P. Kaushish, p. 285)
Semicrystalline polymers are materials used widely in the machinery construction and chemical industries, among others, where they are prized for their chemical and heat resistance. Their advantageous properties
can be further enhanced by means of solid-phase processing, which includes a number of approaches based on plastic deformation, mostly aimed at creating highly oriented states.1 One of these methods
is solid-state extrusion, which normally involves forcing a polymer through a conical- or slot-shaped die. The technique increases the rigidity and strength of polymers, but it also significantly reduces the initial
cross-section of the billet (semifinished cast). A new method of solidphase processing called severe plastic deformation (SPD) is free of the drawbacks of conventional extrusion.
( Victor Aleksandrovich Beloshenko, Victor Nikolayevich Varyukhin,Yuri Vasilievich Voznyak, and Andrei Vasilievich Voznyak, Equal-channel, multiple-angular extrusion of semicrystalline polymers, pg. 1 )
Semi-crystalline Polymers: (18.03.2011-13:44) ( Old )
Unlike amorphous polymers, semicrystalline polymers have some regions where the polymer chains are arranged in specific spatial patterns relative to the other polymer chains within their polymer matrix. Segments of polymer backbones, from either adjacent polymer molecules or within the same polymer molecule (polymer chain folded back on itself) are aligned in an orderly manner with the exact same spatial arrangement and inter-or intramolecular distance from one set group of atoms to the next. Semicrystalline polymers contain both amorphous and crystalline regions within the same polymer matrix.
(Giles H.F. et al, Extrusion: The Definitive Processing Guide and Handbook, p.181)
Semi-crystalline Polymers ( Old )
Long polymer chains consisting of identical monomeric units are, in principle, capable of being organized into crystalline arrays. Usually the chains are parallel bundles and the unit cell is based in some elementary way on the monomeric repeat unit. However, because of their great chain lengths it is kinetically difficult for polymers to form large crystals or to crystallize completely. In the case of quiescent crystallization from the melt the common morphology involves very thin lamellar crystals in which the crystallizing chains fold back and forth across the growth face. A given chain may be incorporated into several lamellae where the latter are organized in ribbon-like sheaves. It is inevitable that a considerable fraction of chain units will be constrained from being laid down on the growth faces. An appreciable fraction of uncrystallized material results. The local organization is that of stacked lamellae separated by amorphous layers. Thus crystallizable polymers are typically semi-crystalline two-phase systems. The degree of crystallinity, i.e., the volume of the crystal phase relative to the specimen volume can vary according to the crystallization conditions. Slow cooling versus rapid quenching, annealing etc. are typical variables. Higher degrees of crystallinity tend to be accommodated by thicker crystal lamellae with a relatively minor role for the amorphous interlayer thickness.
(Polymer Dynamics and Relaxation, By Richard Boyd University of Utah, By Grant Smith University of Utah)
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