Basic Design Criteria

2 DESIGN OF A RADIOTRACER EXPERIMENT 4.2.1 Basic Design Criteria 

The use of radiotracers is dependent on certain basic assumptions being fulfilled. The first assumption, mentioned above, is that the radioactive isotopes of a given element behave identically as the stable isotopes of the same element. Actually, this assumption is not exactly true. The difference in masses between radiotracer nuclei and stable nuclei can cause a shift in the reaction rate or equilibria (the isotope effect). It is true, however, that in most cases the isotope effect does not significantly affect the utility of the radioisotope method. Since the degree of chemical bond stability due to vibrational motion is directly related to the square root of the masses of the isotopes involved, it is apparent that an isotope effect will be of significance only for elements of low atomic weight (at wt 25). 

In the case of radioactive 14C and stable 12C, there is a 15% difference in mass that may affect the outcome of some studies. In general, one should note that the so-called isotopic effect, in reality, should be considered from the standpoint of the two basic types the intramolecular and the intermolecular isotopic effects. 

In addition, one must remember that as the result of radioactive decay, the daughter atom is usually a different chemical element than the mother atom. One must be sure that the presence of these foreign species and any related equilibria does not affect the observations. (For example, if both the mother and daughter atoms are (3 emitters, then one might see a increase in the count rate due to the inability to distinguish the (3 particles from the tracer and its daughter.) 

Most importantly, the radionuclide and the stable nuclide must undergo isotopic exchange. In practice, this means that the tracer and the stable atom must be in the same redox state. By heating or using redox cycles, the experimenter must assure this to be true. Anomalous experimental results have frequently been traceable to the chemical form of the administered radiotracer. Since reactor production of radionuclides often results in side reactions (see Chapter 10), various oxidation states may be present when the sample is produced. In one case involving phosphate-32P uptake in plants, the unexpected experimental results were explained by the fact that a large percentage of the tracer dose was actually in the form of phosphite-32P. 

---

Basic design criteria which need to be taken into consideration when designing a storage tank will include ... 

In this section, the sensitivity characteristics of HRI-coated LPGs have been investigated to outline their dependence on the overlay thickness and mode order. In addition, the experimental results here presented provide the basic design criteria for the development of highly sensitive in fiber refractometers and chemical sensors for specific SRI ranges. 

Basic design criteria developed for these wooden structures could be modified as required to make them suitable for the support of chemically-resistant masonry. 

The basic design criteria used for a continuous crystallizer also apply to a batch crystallizer. These criteria are to ... 

Since seismic microzonation for definition of the effects of the local soil conditions was not performed for the site, approximate values were obtained using the results from detailed geological and geotechnical investigations done at a nearby location. The basic design criteria and requirements for the structure were ... 

The basic principles of adhesive joint design are well known and various standard configurations are available. Irrespective of joint geometry, the basic design criteria are the same. They are ... 

Standardize basic design criteria to ensure the interoperability of fibers from the various suppliers... 

In the previous sections, the fundamental kinetic equations that can be used to correlate experimental data and to calculate ammonia production under given operating conditions have been discussed. Chemical and physical factors, such as mass, heat, and momentum transfer, which could limit the available active surface of the catalyst and the reaction rate in industrial service, have also been mentioned and evaluated. In the following section, we shall consider the basic design criteria... 

In all the configurations described it is assumed that the basic design criteria specified in lEC 65A WGIO Annex A are adopted to the recommended or highly recommended levels. 

The four basic design criteria in the fuel rod design are as follows, for both normal and abnormal transients ... 

The fuel rods are to be internally pressurized with helium gas as in BWRs and PWRs. The initial internal pressure of the fuel rods should be optimized to minimize the stresses and especially the pressure difference on the cladding. However, the internal pressure should not exceed the normal operating coolant pressure (25 MPa) to prevent any creep deformations that causes the gap between the pellet and cladding to increase. The four basic design criteria were determined to ensure the fuel integrity at all anticipated transients based on simple, but conservative evaluations [30]. 

Redundancy and diversification - In order to achieve the requested system reliability and avoid common failures, these issues are basic design criteria. 

The absorption rate on the most exposed element determines the maximum absorption rate and must be used to make the radiation heat balance. This is the basic design criterion. 

Mahe et al. [20] of the LVMH Group, Christian Dior, reported a microstructured device for the production of emulsions on demand. The basic design criterion was that the microstructured device is hand operated, i.e. emulsification has to be achieved with relatively low external forces and internal pressures. Assuming the thumb as most powerful digit, required forces for operation higher than 20 N cannot be accepted. 

The mass-transfer coefficients depend on complex functions of diffii-sivity, viscosity, density, interfacial tension, and turbulence. Similarly, the mass-transfer area of the droplets depends on complex functions of viscosity, interfacial tension, density difference, extractor geometry, agitation intensity, agitator design, flow rates, and interfacial rag deposits. Only limited success has been achieved in correlating extractor performance with these basic principles. The lumped parameter deals directly with the ultimate design criterion, which is the height of an extraction tower. 

Basically, the criterion for specifying events as accidents is that the losses are so important that they need to play a central role in the design and tradeoff process. In the outer planets explorer example in chapter 7, some of the losses involve the mission goals themselves while others involve losses to other missions or a negative impact on our solar system ecology. 

Designs of units with WWER under operation in Ukraine were developed in 70-s. The basic safety criterion laid into these designs was to provide for safety under all the design basis accidents/at that time, exclusively deterministic approach to safety level assessment was adopted as the basis. 

The model compound work for the three basic systems is summarized in Figure 1. A finding of no significant reduction in a system is designated by an x ed arrow. Our criterion of successful reduction requires that significant quantities of the starting... 

The FPL vertical wall furnace used in our study was described in some detail by Brenden and Chamberlain (6). This furnace is normally used to evaluate the fire endurance of wall assemblies. The basic guidelines for the furnace test method are given in the ASTM E-119 standard (5). The method was designed to evaluate the ability of a structure to withstand a standard fire exposure that simulates a fully developed fire. The furnace is gas fired, and its temperature is controlled to follow a standard time-temperature curve. A load may be applied to the assembly. The failure criterion can be taken as time at burnthrough, structural failure, or a specified temperature rise on the unexposed side of the wall—whichever comes first. The construction of the furnace is not specified in the ASTM E-119 standard. 

The basic idea proposed by Skogestad and Morari is to design the controller so that the closedloop resonant frequency of the system occurs at a frequency that is lower than the region where the uncertainty becomes significant. For example, suppose Kp = Tp = 1 in Eq. (16.44). If a proportional controller is used and a tuning criterion of - - 2 dB maximum closedloop log modulus is assumed, the value of the controller gains and closedloop resonant frequencies for different deadtimes are hsted below. 

Four blades are ordinarily considered a desirable minimum for mediumsized fans, with eight blades a minimum for large diameters. Twelve blades are a practical maximum. Fan diameters are basically determined by the volume of air to be handled. Air velocities through the fan range from 1200 to 2500 fpm. An economic design value is about 1800 fpm. Acceptable fan blade tip speeds, with low noise as the criterion, vary with the type tower, the type of fan cylinder and the blade tip clearance. 

In a simplistic treatment, of course, an isolated metal ion could itself be viewed as a receptor for anions as it fulfills the basic criterion of reversible anion binding. The concept of an anion receptor, however, requires a reversal of this metal-centered viewpoint. For the purposes of this chapter, a receptor will be considered as a molecule designed for binding anions, which does so through a combination of bonding interactions (rather than through a single... 

The /-test is widely used in analytical laboratories for comparing samples and methods of analysis. Its application, however, relies on three basic assumptions. Firstly, it is assumed that the samples analysed are selected at random. This condition is met in most cases by careful design of the sampling procedure. The second assumption is that the parent populations from which the samples are taken are normally distributed. Fortunately, departure from normality rarely causes serious problems providing sufficient samples are analysed. Finally, the third assumption is that the population variances are equal. If this last criterion is not valid then errors may arise in applying the /-test and this assumption should be checked before other tests are applied. The equality of variances can be examined by application of the F-test. 

Decision criteria relates to the safety critical deterioration level. It is necessary to determine this level to be able to make appropriate decisions regarding further action. Usually a first basic intervention level is defined according to relevant codes, standards or internal company requirements. A minimum required wall thickness is usually determined due to a stress criterion and depends on allowable stress, design pressure, pipe dimensions and material strength. When deterioration beyond this basic intervention level is revealed through inspection, further actions must he decided. When the basic intervention level is reached, there may... 

---