Texture characteristics geometrical

The properties included under the heading texture are found mainly in macromolecular food components, especially proteins and polysaccharides, as well as products of their interactions and associations with other food ingredients, first and foremost with water. Texture impHes those characteristics of foods that cause tactile or haptic sensations registered by receptors in the oral cavity. Touch by hands is very important. Auditorial perceptions such as crispness are related to a range of textural characteristics. Geometric attributes of texture that simultaneously cause visual and haptic sensations, often referred to as shape and appearance (such as particle size or size of the whole food), are closely related to food colour. The term consistency describes the texture aspects related to physical (mechanical) properties of food, which are also called rheological properties (see Section 7.8.4.1). 

The third distance, perhaps the most relevant to reactions on surfaces, is the actual distance traversed by a diffusing molecule. This is a very complex issue which we only begin to understand. The diffusional distance reflects not only the geometric considerations made above, but also the facts that the surface is energetically heterogeneous, and that the diffusion is some combination of movements which follow closely the surface features, and of jumps from pore-wall to pore-wall and from one tip to the next. Obviously this diffusional distance is also a function of the temperature and of the solvent interfaced with the solid. Furthermore, since different types of connectedness can yield the same D value, this textural characteristic is an additional parameter to be considered (the fracton or spectral dimension (IS)). In view of this complex picture, what is then the practical advise Under the current state of art, the best one can do is to get a preliminary estimate of d from eq s [4]-[6] the direct observation of actual diffusional process in disordered systems, is still in its infancy. For some recent studies see ref. 16,17. 

Heterogeneous porous networks can be simulated taking into account characteristics proper of real media such as variations in pore size and connectivity. Real substrata display also physical or geometrical restraints that should be taken into account for an adequate modeling. Sorption characteristics can be studied in these simulated 3D networks. Comparison with actual isotherms of real porous media in order to infer or predict textural parameters should be the next step of this research. 

Some geometric transport models are based on solid characteristics rather than on properties of the pore space itself. By assuming a particular packing arrangement it is possible to infer the pore space geometry from information on the size and shape of the solid particles (Coelho et al., 1997). While this approach may be applicable to sieved and repacked soil columns, it is often inappropriate for undisturbed samples, with pore characteristics that depend more on soil structure than on soil texture. Thus, models to predict solute dispersion from the properties of particles in packed beds (e.g., Aris Amundson, 1957 Koch Brady, 1985 Ras-muson, 1985) are not the main focus of this review. 

ISO 3274 1996 Geometrical Product Specifications (GPS) — Surface texture Profile method — Nominal characteristics of contact stylus instruments. 

DIN EN ISO 3274 1998-04 (1998) Geometrical product specification (GPS). Surface texture Profile method Nominal characteristics of contact (stylus) instruments. 

ISO 25178- 601 2010 Geometrical product specifications (GPS) -Surface texture Areal - Part 601 Nominal characteristics of contact (stylus) instruments ISO/DIS 25178- 604 Geometrical product specifications (GPS) - Surface texture Areal - Part 604 Nominal characteristics of non-contact (coherence scanning interferometry) instruments... 

Surface roughness terminology surface and its parameters Surface character geometrical characteristics of surface texture terms, definitions, symbols... 

---