Natural strain

Concern over the discharge of such strains into the environment. Attempts have therefore been made to incorporate safeguards so that the strains are unlikely to survive in competition with natural strains in the ecosystem. 

Release of enzymes is not considered a problem because detergent enzymes occur naturally in the environment. In fact Bacillus species, common hosts for the production of enzymes, are found in the soil and are part of the microbial population used in com-posting.f Nevertheless, the bacterial fermentations carried out in enzyme plants are carefully contained, and no live organisms should be detectable in the final enzyme product. As an additional safety measure, engineered bacterial strains are designed so that they cannot compete effectively with natural strains in the environment. 

On the other hand, natural strain (also called logarithmic or Hencky s strain) C rrue results from integration of infinitesimal strains (Swyngedau et al., 1991). However, it is only applicable to particulate materials forming a stable or cohesive structure. 

Natural strains are thus better to use in the analysis of plastic flow. 

The true strain, also called the natural strain, denoted by e, takes into account that the initial section A of the material changes with the applied load. It is defined as the Napierian logarithm of the ratio of the actual cross-section area of the sample, A, at a given applied load f to the initial cross-section area A ... 

Fig. 14. Elongation speed dependence of true stress-elongation time and true stress- natural strain curves for iPP.

The logarithmic strain has also been termed the natural strain by Nadai [4], and is discussed by other authors, for example Rees [5]. In terms of the engineering strain e,... 

HAM G.E. 1980. Inoculation of legumes with Rhizdbium in competition with naturalized strains. In Nitrogen fixation. Volume 2. Eds. 

---