Factor limits

Feed purification. Impurities that enter with the feed inevitably cause waste. If feed impurities undergo reaction, then this causes waste from the reactor, as already discussed. If the feed impurity does not undergo reaction, then it can be separated out from the process in a number of ways, as discussed in Sec. 4.1. The greatest source of waste occurs when we choose to use a purge. Impurity builds up in the recycle, and we would like it to build up to a high concentration to minimize waste of feed materials and product in the purge. However, two factors limit the extent to which the feed impurity can be allowed to build up ... 

As a field matures, bottlenecks may appear in other areas, such as water treatment or gas compression processes, and become factors limiting oil or gas production. These issues can often be addressed both by surface and subsurface options, though the underlying justification remains the same the NPV of a debottlenecking exercise (net cost of action versus the increase in net revenue) must be positive. 

There are difficulties in making such cells practical. High-band-gap semiconductors do not respond to visible light, while low-band-gap ones are prone to photocorrosion [182, 185]. In addition, both photochemical and entropy or thermodynamic factors limit the ideal efficiency with which sunlight can be converted to electrical energy [186]. 

The factor limiting the resolution in ultraviolet photoelectron spectra is the inability to measure the kinetic energy of the photoelectrons with sufficient accuracy. The source of the problem points to a possible solution. If the photoelectrons could be produced with zero kinetic energy this cause of the loss of resolution would be largely removed. This is the basis of zero kinetic energy photoelectron (ZEKE-PE) spectroscopy. 

A number of factors limit the accuracy with which parameters for the design of commercial equipment can be determined. The parameters may depend on transport properties for heat and mass transfer that have been determined under nonreacting conditions. Inevitably, subtle differences exist between large and small scale. Experimental uncertainty is also a factor, so that under good conditions with modern equipment kinetic parameters can never be determined more precisely than 5 to 10 percent (Hofmann, in de Lasa, Chemical Reactor Design and Technology, Martinus Nijhoff, 1986, p. 72). 

In principle GD-MS is very well suited for analysis of layers, also, and all concepts developed for SNMS (Sect. 3.3) can be used to calculate the concentration-depth profile from the measured intensity-time profile by use of relative or absolute sensitivity factors [3.199]. So far, however, acceptance of this technique is hesitant compared with GD-OES. The main factors limiting wider acceptance are the greater cost of the instrument and the fact that no commercial ion source has yet been optimized for this purpose. The literature therefore contains only preliminary results from analysis of layers obtained with either modified sources of the commercial instrument [3.200, 3.201] or with homebuilt sources coupled to quadrupole [3.199], sector field [3.202], or time-of-flight instruments [3.203]. To summarize, the future success of GD-MS in this field of application strongly depends on the availability of commercial sources with adequate depth resolution comparable with that of GD-OES. 

The creep strength of steels is a factor limiting the maximum temperatures for such high-pressure equipment as shells and stirrers of high temperature reactors. Table 3.10 presents creep data for temperatures ranging from 400 to 600°C. The stress for 1% creep in 100,000 hours (which is a design criterion) is accepted to be not less than two-thirds of the creep stresses. 

Corrosion of the tank is the major factor limiting water heater lifetimes. The A. O. Smith company invented the glass-lined tank in 1939, where an enamel coating is baked onto the inside surface of the tank at high temperatures. The technology has subsequently been adopted by other manufacturers, although other linings are used such as cement or plastic. 

Nickel and nickel alloys possess a high degree of resistance to corrosion when exposed to the atmosphere, much higher than carbon and low-alloy steels, although not as high as stainless steels. Corrosion by the atmosphere is, therefore, rarely if ever a factor limiting the life of nickel and nickel alloy structures when exposed to that environment. 

The large air flows needed, the power to move them, and the resulting noise levels are the factors limiting the use of air-cooled condensers. 

Industrialised countries that have developed the technologies are not the countries suffering population explosions and food shortages. The so-called developing countries that have the population and food problems, do not generally have the industrial base and technological expertise necessary to operate large-scale processes. These factors limit the application of SCP processes. 

Needless to remind that the above practical promotional rules are applicable for modest (e.g. <0.2) coverages of the promoting species so that site-blocking by the promoter does not become the dominant factor limiting the catalytic rate. 

In human exercise physiology, fatigue is often defined as an inability of a muscle or a group of muscles to sustain the required or expected force (Edwards, 1981). This definition is very applicable for the study of factors limiting dynamic or isometric exercise in intact organisms at varying intensities. 

The rate of recruitment is one of the most frequent factors limiting the speed of clinical evaluations. Particularly in some areas, such as oncology, finding... 

Atomic force microscope (AFM) is a powerful nanotechnology tool for molecular imaging and manipulations. One major factor limiting resolution in AFM to observe individual biomolecules such as DNA is the low sharpness of the AFM tip that scans the sample. Nanoscale 1,3,5,7-tetrasubstituted adamantane is found to serve as the molecular tip for AFM and may also find application in chemically well-defined objects for calibration of commercial AFM tips [113]. 

CARBONARO M, GRANT G, CAPPELLONi M, puszTAi A (2000) Perspectives into factors limiting in vivo digestion of legume proteins antinutritional compormds or storage proteins JAgric Food Chem. 48 742-9. 

Rasche ME, MR Hyman, DJ Arp (1991) Factors limiting aliphatic chlorocarbon degradation by Nitrosomonas europaea cometabolic inactivation of ammonia monooxygenase and substrate specificity. Appl Environ Microbiol 57 2986-2994. 

Experimental screening established that compound 42 shown in Fig. 8.11 disrupts ZipA-FtsZ protein-protein interaction. However, previous studies suggested potential issues with toxicity associated with this class of compounds. Additionally such amine-substituted pyridyl-pyrimidines are heavily patented in the context of kinase inhibition. Both of these factors limit the scope of the subsequent lead optimization process, to transform this compound into a viable drug. Knowledge that compound 42 was a micromolar inhibitor of ZipA-FtsZ was exploited by searching for molecules that were similar in shape. 

When using TL,- greater than 1 mM (equiv. 3 mM LA), product appearance seems to be independent of TL,- concentration. The presence of the first reaction is the major factor limiting the production rate of HP. 

Kosmider J. (1990). Olfactory adaptation a factor limiting warning role of odor. Med Pr 41, 142-147. 

Boopathy, R., Factors limiting bioremediation technologies, Biores. Technol., 74, 63-67, 2000. 

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