Strength profiles

Kinetically indistinguishable chain mechanisms can be characterized by different ionic strength profiles, as was apparently first demonstrated in a study this author conducted with D. A. Ryan on the reaction of (aqua)-2-propylchromium cation with oxygen.17 This reaction was presented in Chapter 7. Two schemes that are consistent with the rate law are as follows ... 

The predicted ionic strength profiles for various substrates in the chain mechanisms of Schemes C, D, and E, Eqs. (9-79M9-86), are shown for substrates of different ionic charges. 

The pole strength profiles obtained in the outer valence region of the 1,3-trans butadiene, 1,3,5-trans hexatriene and 1,3,5,7-trans octatetraene compounds relate also typically to that found (10) with low-gap hydrogen chains. They nicely reflect the competition for intensity between the main and the correlation i.e. satellite) bands in that region. In both cases, the less energetic (HOMO LUMO (10,12)... 

A wide range of operating conditions and design philosophies affect mercury cell efficiency. For example, the fundamental distinction between a resaturation and a waste brine process influences the temperature and brine strength profile along the length of the cell and hence the overall efficiency. Another important factor is the quality of the brine. Impurities in the brine can cause base-plate deposits, which tend to reduce the anode/cathode gap. This gradual reduction in gap requires either manual or automatic adjustment and, eventually, the cell must be taken off-line and the thick mercury removed. 

Figure 5.17. Electric potential profile yflz) auid field strength profile E(z) in the multilayer Stem model of Bohmer et al.21.

The physical strength of a tablet is also dependent on its dimensions. In the construction of a force-strength profile, all tablets will have the same cross-sectional area as the same tooling will have been used. However, as the compressive force is changed, so will the tablet height. Hence, comparisons made on the basis of breaking strength will not be truly valid. 

Confusion can often arise in the units that are used to express compression force or pressure and the strength of the tablet. Table 7 gives examples of units that have been used recently for the axes of tablet strength profiles. Comparison between different tablet formulations would be greatly facilitated if authors used and journal editors insisted on the use of the SI system of units. The SI unit of length is the meter, that of force the Newton and that of pressure the Pascal. The unit for physical strength is the Newton and that of tensile strength calculated from Eq. (1) is the Pascal. 

Table 7 Some units used for the construction of tablet strength profiles...

By definition, direct compression diluents are intended to be mixed with other ingredients. Therefore, not only should the pressure-tablet strength profile of the diluent be determined, but also should those of mixtures of the diluent with an active ingredient. The capacity of a direct compression diluent is the proportion of another ingredient that can be mixed with it while still obtaining tablets of acceptable quality. The definition of acceptable will depend on the purpose for which the tablets are required. 

The magnitude of the effect that a given active ingredient will have on tablet properties will clearly depend on the tabletting properties of that substance. If it is also capable of direct compression, then the effect will not be great. If, however, it is a substance that is difficult to compress into tablets, then it will cause a marked deterioration in tablet quality when mixed with the diluent. Therefore, for a reliable test of capacity, the direct compression diluent should be mixed with a standard substance and tabletted under standardized conditions. The pressure-strength profiles of the mixtures can then be constructed. Paracetamol and ascorbic acid have been used as standards. 

The effect of the active ingredient on flow properties can be determined at the same time by calculating the uniformity of weight of the tablets used to prepare pressure-strength profiles. 

Table 2 Areas under pressure-tablet strength profiles for mixtures of ascorbic acid and direct compression lactitol...

Figure 11.11 Compaction pressure/tensile strength profile. Typical plot for a pharmaceutical material.

Possess a prolonged strength profile, especially during the initial postoperative period, as braided multifilament or monofilament sutures... 

Tensile and in vitro and breaking strength retention data of typical monofilament sutures made of the polymers described in Section 8.3.2 are summarized in Table 8.6. The data in Table 8.6 indicate that the polymers described in Table 8.5 can be converted to monofilament sutures with competitive strength retention and breaking strength profiles as the commercially available braided sutures made of polyglycolide or 90/10 poly(glycolide-co-/-lactide). 

Idealized shear strength profiles for homogenous marine deposits that are (1) NC clay, (2) UC clay, and (3) OC clay are presented in Figure 8.31. A review of Figure 8.31a shows that the NC clay profile exhibits a linear shear strength behavior starting at zero at the... 

Idealized strength profile in homogeneous clay, (a) NC strength profile (b) UC strength profile (c) OC strength profile. 

Typical clay strength profiles. (From Chaney, R., and Fang, H.Y., Static and dynamic properties of marine sediments A state of the art. In Marine Geotechnology and Nearshore/Offshore Structures. STP 923, Chaney, R.C., and Fang, H.Y., eds., ASTM Press, Philadelphia, PA, pp. 74-111,1986. Reprinted with permission Copyright ASTM.)... 

The strength profile is determined for two different consolidation levels corresponding to no drainage and full drainage under the submerged weight of the platform. The effect of cyclic load on the reduction of shear strength has also to be taken into account. 

For short-term or undrained loading analysis (( ) = 0) the factor N is zero and the factor N c is selected from Figure 10.43 for the anticipated relative embedment depth D/B and soil cohesion (a distance B above the anchor) in the soft rupture zone. The soil cohesion can be measured in place with a field vane or cone penetrometer or determined from laboratory tests on core samples such as the unconfined compression or triaxial CU test. If soil strength data are not available, the strength profile can be estimated using d CTot = 0.30, where the vertical effective stress (o J is estimated using a buoyant unit weight of 4 kN/m. ... 

Ting et al. (2005) reported on a case of investigation carried out in Quaternary deposits at Slim River Perak, Malaysia. Figure 3.17 below shows the characterized strength profile of the ground. The characterized strength profiles shown below were based on Cone Penetrometer Test (CPT) and Field Vane Shear (FVS) test results and limited to depths of 15 m. 

A needle enables die suture strand to be passed through the tissues that are to be approximated. The most important characteristics of a needle include sharpness, strength, profile, corrosion resistance, and durability. Additional charactmistics sudi as length, curvature, and wire diameter are considered by the surgeon during product selection [3]. 

Figure 12.27 Cross-sectional tensile strength profile for 30 wt% GFRP composites. , Long GFRP , P7-30FG-A729H A, P7-30FG-A729G X, P-30FG-0100. (Data given in Table 12.11.)...

Another approach is to make ultra-fine (submicron diameter) filaments by the island-in-the-sea technique, where the sacrificial matrix (sea) polymer is removed in a subsequent post-spinning process. Thus, by using bicomponent spinning technology, the material strength profile, resorption profile, and the biological properties can be engineered into the fiber to meet specific medical requirements. 

More importantly, like the 1,6 PA, unannealed test coupons of the 1,4 PA display no change in physical strength between coupons subjected to cobalt and unirradiated test samples. In addition, like the 1,6 PA an induction period in the in-vitro physical strength is observed. However, unlike the 1,6 PA, the 1,4 PA displays only a 3 week induction period, followed by a linear decrease strength profile. The nature of this difference between 1,6 PA and 1,4 PA is believed to be due to the increased hydrolyzability and hydrophilicity of the 1,4-bis acid in comparison to that of the 1,6-bis acid monomer. It should be noted that similar behavior to that of the annealed 1,6 PA is observed for annealed coupons of the 1,4 PA. 

Strength profile after pre-damage (with control experiments) and stepped load Increases GFP-BD [509]... 

Tensile strength profile of polyamide imide with 3% Ti02 and 0.5% PTFE during aging at 250 °C (specimen thickness 3.2 mm) [572]... 

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