Specific stress

The concept of tensile stress is simple and straightforward. However, the cross-sectional areas of mar r fibers are not well-defined due to their tmique cross-sectional shapes. One useful parameter to describe the fiber cross-sectional fineness is the linear density (ji), i.e., mass per unit length. For fibers with comparable bulk densities, their cross-sectional area is proportional to the fiber linear density. Hence, the term specific stress (ct) often is used, especially in the textile conununity  

Common units for specific stress are gram per denier or gram per tex. Denier is the unit of fiber or yam measurement equal to the weight in grams of 9,000 meters of fiber or yam, while tex is the unit of fiber or yam measurement equal to the weight in grams of 1,000 meters of fiber or yam. 

When specific stress is used in calculating the tensile modulus, the modulus unit becomes gram per denier or gram per tex. 

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Table 10-56 gives values for the modulus of elasticity for nonmetals however, no specific stress-limiting criteria or methods of stress analysis are presented. Stress-strain behavior of most nonmetals differs considerably from that of metals and is less well-defined for mathematic analysis. The piping system should be designed and laid out so that flexural stresses resulting from displacement due to expansion, contraction, and other movement are minimized. This concept requires special attention to supports, terminals, and other restraints. 

For purposes of this specification, stresses in the individual members of a latticed or trussed structure resulting from elastic deformation and rigidity of joints are defined as secondary stresses. These secondary stresses may be taken to be the difference between stresses from an analysis assuming fully rigid joints, with loads applied only at the joints, and stresses from a similar analysis with pinned joints. Stresses arising from eccentric joint connections, or from transverse loading of members between joints, or from applied moments, must be considered primary stresses. 

Corrosion dominated (solution requirements highly specific) Stress dominated (solution requirements less specific) ... 

The pressure necessary to produce a specific stress in a vessel depends on the thickness of the vessel, the vessel diameter, and the mechanical properties of the vessel wall.7 For cylindrical vessels with the pressure p not exceeding 0.385 times the mechanical strength of the material SM... 

How specific stresses provoke nucleolin redistribution remains an open question. A block of ribosomal transcription cannot account for the whole phenomenon as shutdown of RNA polymerase I activity by actinomycin D induces rather a nucleolar-to-cytoplasmic change in nucleolin localization (Daniely and Borowiec, 2000). Interestingly, the relocalization is dependent on p53 since it does not occur in cell... 

The MT biomarkers in flounder liver correlate with gradient of contamination in both sediment and fish (Fig. 3, Fig. 4). This may be an indicator of specific stress by organotins, although the expected correlation was not found for metals such as Zn and Cd. Surprisingly, there was a good correlation between the concentration of MT and chemical exposure to total organotin in sediment (r =0.7304). In a few studies it has been shown that, in fish, detoxification of TBT is induced by metalloproteins (Kawano et al., 1996 Padros et al., 2000). 

At the end of Section 5.4.2.5, the statement was made that most continuous, unidirectional fiber-reinforced composites are used to produce layers that are subsequently assembled to form laminate composites. In this section, we expound upon this statement by examining the mechanics of laminate composites, first through a generalized description of their mechanics, then with some specific stress-strain behavior. 

ASTM D1456,1986 (2001). Rubber property-Elongation at specific stress. 

The stresses used in a creep test are chosen in two ways. First, a value is chosen from oscillatory tests (specifically stress or strain amplitude sweeps at 1 Hz or 10 rad/sec unit hs.i) to define the linear region. Using two to five different values, the sample is taken from a linear viscoelastic response to the onset of... 

Waterside problems that lead to decreases in efficiency and material deterioration can be caused by a variety of mechanisms, such as electrochemical corrosion and deposition of foulants. These problems can be exacerbated by low flow, poor operational practice, process contamination, or specific stresses. It is also important to try to determine cause and effect relationships in order to provide a logical and practical water treatment solution. Such a solution will usually involve some form of cleaning, plus a combined engineering and chemical action plan. Inspection may be made easier by the use of a Boroscope or similar optical/video recording device. The color, texture, and quantity of all deposits should be noted, measurements of pits taken, and microbiological contaminants analyzed. It may be useful to conduct biocide efficiency tests on bacterial slimes. The period when a heat exchanger is open for inspection may be an opportune time for the permanent installation of ports for corrosion-monitoring probes. 

It now seems probable that specific disturbances occur in the immune system in psychiatric illness that are not artefacts of non-specific stress factor, institutionalization or medication. The known effects of the neuroendocrine system on the immune response, and the recent evidence that receptor sites for neurotransmitters and neuroendocrine factors occur on lymphocytes and macrophages, support the hypothesis that immunological abnormalities may assist in precipitating the symptoms of anxiety and depression, commonly symptoms of major affective disorders. 

Various proteins have been identified as markers for general stress in microorganisms or for specific stress like temperature, pH, toxic products, oxygen deficiency for strict aerobes, or oxygen toxicity for anaerobes, etc. most of them are rather small in size. Most work was done with E. coli (for a review see e.g. [53] and with B. subtilis [54]). 

It has been shown in cell culture models of cXj-antitrypsin that Z-oq-antitrypsin in the ER causes expression of a novel set of stress genes with products that have the role of restoring ER function to normal. Z-a,-Antitrypsin induces two signal transduction pathways the ER overload response and unfolded protein response pathways. Via these transduction pathways, the presence of Z-oq-antitrypsin, as opposed to M-(Xj-antitrypsin, induces an hepatic inflammatory response. It is thought that this ER-specific stress response results in hepatic injury. 

A very important diagram for fibres and yams is the stress—strain diagram, where the specific stress is plotted as a function of the elongation (extensional strain) in %. The curve starts at an elongation of zero and ends in the breaking point at the ultimate specific stress (=tensile strength or tenacity) and the ultimate elongation (=strain at break). 

Cucumber, melon, tobacco, and bean varieties, supposedly lacking significant resistance to particular diseases, can be made highly resistant systemically by limited infection prior to severe exposure to pathogens. Injury and non-specific stress do not elicit persistent systemic resistance. 

Figure 4.8 cont.) (b) Specific stress-strain curves of Lycra (Spandex) and natural rubber fibers (Wilson, 1967,1968). 

Since each monomer of the Jun/Fos heterodimer can be phosphorylated separately, each can make an independent contribution to the transcriptional activity of the complex. For example, exclusive phosphorylation of a single threonine, Thr232, located in the N-terminal region of Jun by JNK (the Jun amino-terminal kinase), gives a characteristic and specific stress response. 

Foamed PDMS elastomers generally play an important role in a number of specific stress absorbing applications. Reports on Polystyrene and Polyurethane foams have tended to dominate the literature in recent years. Such systems generally exhibit high stiffness to weight ratios and some unique mechanical properties that are dependent upon the microstructure of the foam and the properties of the polymer making up the cell walls 10). In general, the desirable material property requirements of foams may be summarised as shown below ... 

Figure 15.6 Tensile stress versus tensile strain (a) and specific stress versus strain curves (b) for some reinforcing fibers. (From Ref. 7.)...

Developing an understanding of the intrinsic stability of the drug substance does not eliminate the need for specific stress testing of the... 

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