Model Young

A number of nutrients affect bone integrity early in life. While the role of certain minerals and vitamins bearing on skeletal integrity is well established, that of protein remains controversial, especially when consumed in excessive amounts. Protein-included calciuric effect as observed in adult man and animals may also occur early in life and thus conceivably affect peak bone mass adversely, particularly when calcium intakes may be marginal. In studies reported here (test model young female rats), it was found that a diet approaching adequacy in protein and based equally on plant and animal sources would favor some parameters which bear on skeletal mass at maturity more than other combinations of protein consumed. 

Distillation tray models Young and Stewart (1992, 1995) 2b 1,1,1 AE GREG 152-157... 

Two parent body models have been proposed to explain the oxygen isotopic composition of carbonates in CM chondrites (i) a closed system, two reservoir model (Clayton and Mayeda, 1984, 1999) and (ii) a fluid-flow model (Young et al., 1999 Young, 2001 Cohen and Coker, 2000). Current oxygen-isotopic data are generally most consistent with the closed-system model, but can also be reconciled with the fluid-flow model if the CM chondrites sample a restricted region of the CM asteroid (Benedix et al., 2003), just downstream of the model alteration front proposed by Young (2001). 

The model presented in Figure 12.2 integrates the dynamic schema model developed by Price (2002) with the traditional Beckian model of stress (Beck 1987 Beck et al. 1985) outlined in Chapter 1 and Young s schema-focused model (Young et al. 2003) presented earlier in this chapter. The model places particular emphasis on the re-enactment of early maladaptive schemata (EMS) and behavioural coping strategies in the context of the workplace in the causation and maintenance of occupational stress. 

In terms of this simple model. Young s modulus depends sensitively on the interatomic distance in the solid. 

Wu Y P, Jia Q X, Yu D S and Zhang L Q (2004) Modeling Young s Modulus of Rubber-Clay Nanocomposites Using Composite Theories, Polym Testing 23 903-909. 

Yung K C, Wang J and Yue T M (2006) Modeling Young s Modulus of Polymerlayered Silicate Nanocomposites Using Modified Halpin-Tsai Microinechanical Model, J Reinf Plast Compos 25 847-861. 

The importance of the solid-liquid interface in a host of applications has led to extensive study over the past 50 years. Certainly, the study of the solid-liquid interface is no easier than that of the solid-gas interface, and all the complexities noted in Section VIM are present. The surface structural and spectroscopic techniques presented in Chapter VIII are not generally applicable to liquids (note, however. Ref. 1). There is, perforce, some retreat to phenomenology, empirical rules, and semiempirical models. The central importance of the Young equation is evident even in its modification to treat surface heterogeneity or roughness. ... 

The effect of surface roughness on contact angle was modeled by several authors about 50 years ago (42, 45, 63, 64]. The basic idea was to account for roughness through r, the ratio of the actual to projected area. Thus = rA. lj apparent and similarly for such that the Young equation (Eq.-X-18) becomes... 

Ruch and Bartell [84], studying the aqueous decylamine-platinum system, combined direct estimates of the adsorption at the platinum-solution interface with contact angle data and the Young equation to determine a solid-vapor interfacial energy change of up to 40 ergs/cm due to decylamine adsorption. Healy (85) discusses an adsorption model for the contact angle in surfactant solutions and these aspects are discussed further in Ref. 86. 

B. Semiempirical Models The Girifalco-Good-Fowkes-Young Equation... 

Fig. 2. Young s modulus corrected for porosity as a function of preferred orientation curve is based on theoretical model where = rayon-based fibers Q — PAN-based fibers and A = pitch-based fibers (2). To convert GPa to psi, multiply by 145,000.

Surface Area and Permeability or Porosity. Gas or solute adsorption is typicaUy used to evaluate surface area (74,75), and mercury porosimetry is used, ia coajuactioa with at least oae other particle-size analysis, eg, electron microscopy, to assess permeabUity (76). Experimental techniques and theoretical models have been developed to elucidate the nature and quantity of pores (74,77). These iaclude the kinetic approach to gas adsorptioa of Bmaauer, Emmett, and TeUer (78), known as the BET method and which is based on Langmuir s adsorption model (79), the potential theory of Polanyi (25,80) for gas adsorption, the experimental aspects of solute adsorption (25,81), and the principles of mercury porosimetry, based on the Young-Duprn expression (24,25). 

The role of oceanic physical chemistry and biochemistry in the enhanced greenhouse future is still uncertain. We have discussed the mechanisms generating a number of potential feedbacks, both positive and negative in their impact. However, new interactions are constantly being discovered in nature, and model representation of them is a rapidly evolving science. At present what we can say is that this is a young field of much intellectual and practical promise. 

In the probabilistic design calculations, the value of Kt would be determined from the empirical models related to the nominal part dimensions, including the dimensional variation estimates from equations 4.19 or 4.20. Norton (1996) models Kt using power laws for many standard cases. Young (1989) uses fourth order polynomials. In either case, it is a relatively straightforward task to include Kt in the probabilistic model by determining the standard deviation through the variance equation. 

The JKR model predicts that the contact radius varies with the reciprocal of the cube root of the Young s modulus. As previously discussed, the 2/3 and — 1/3 power-law dependencies of the zero-load contact radius on particle radius and Young s modulus are characteristics of adhesion theories that assume elastic behavior. 

The preceding restrictions on engineering constants for orthotropic materials are used to examine experimental data to see if they are physically consistent within the framework of the mathematical elasticity model. For boron-epoxy composite materials, Dickerson and DiMartino [2-3] measured Poisson s ratios as high as 1.97 for the negative of the strain in the 2-direction over the strain in the 1-direction due to loading in the 1-direction (v 2)- The reported values of the Young s moduli for the two directions are E = 11.86 x 10 psi (81.77 GPa) and E2 = 1.33x10 psi (9.17 GPa). Thus,... 

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