Field experience

Advantages. The experiment can be carried out with a conventional fast-spuming MAS probe so that it is straightforward to implement. For recording the satellite transition lineshapes it offers better signal-to-noise and is less susceptible to deadtime effects than static measurements. As the effects differ for each value, a single satellite transition experiment is effectively the same as carrying out multiple field experiments on the central transition. 

Formal Theory A small neutral particle at equihbrium in a static elecdric field experiences a net force due to DEP that can be written as F = (p V)E, where p is the dipole moment vecdor and E is the external electric field. If the particle is a simple dielectric and is isotropically, linearly, and homogeneously polarizable, then the dipole moment can be written as p = ai E, where a is the (scalar) polarizability, V is the volume of the particle, and E is the external field. The force can then be written as ... 

Landfilling Methods and Operations To use the available area at a landfill site effectively, a plan of operation for the placement of solid wastes must be prepared. Various operational methods have been developed primarily on the basis of field experience. The principal methods used for landfilling dry areas may be classified as (1) area, and (2) depression. 

Field experience has revealed that one of the major causes of failure of an HT motor is weak insulation, caused by environmental pollution and ageing. 

Note The exact values will depend upon the surface condition of the material and the field experience and skill of the operator. For more accurate details consult the chemical manufacturer. 

This is an average value of metal erosion during the length of service and may vary with soil conditions. In coastal areas, for instance, where the subsoil water is saline, erosion of metal would be much more rapid and a further safety factor must be considered. Field experience will be a better guide to assess this. 

To determine this, it is necessary that certain assumptions, based on field experience, are made for a possible grotinding system and if necessary, further modifications made to anive at the desired results and design ... 

Field experiments have revealed that such currents may be as higlt as up 10 I.S-2.S0 limes the steady state current /,. but will last only up to the first current zero. 

The models you use to portray failures that lead to accidents, and the models you use to propagate their effects, are attempts to approximate reality. Models of accident sequences (although mathematically rigorous) cannot be demonstrated to be exact because you can never precisely identify all of the factors that contribute to an accident of interest. Likewise, most consequence models are at best correlations derived from limited experimental evidence. Even if the models are validated through field experiments for some specific situations, you can never validate them for all possibilities, and the question of model appropriateness will always exist. 

Criteria 2 to 6 are pragmatic criteria which are only applicable to qualitative explanations. These criteria only give qualitative information which is dealt with further below (Section 3.3.3.1). Criterion 7 gives better information with potential test probes (see Section 3.3.3.2). In all the criteria it must be remembered that only mixed potentials can be measured for extended objects to be protected [see the explanation to Eqs. (3-19) and (3-28)]. Criteria 5 and 6 are particularly to be observed for objects [22]. A comparison of the different criteria in field experiments has shown that, besides Criterion 1, good results are obtained with Criterion 3 [26]. 

Table 4-2 shows as an example of the relationship between the results of field experiments [11] and the class of soil. In general, the time dependence of the corrosion rate can be represented as follows for t > 4a ... 

Table 4-3 Data on local corrosion from field experiments (after 12 years [11] and 6 years [ 12]).

The r values from Eq. (5-1) for the most important materials for pipe coatings are given in Table 5-1. Table 5-2 contains results of long-term field experiments. For comparison, the values of r°are included in Table 5-1. It can be seen that values are always smaller than r values, which is apparently due to the absorption of water when the coating is immersed in the medium. A marked reduction in the coating resistance has been observed with increasing temperature for resins [9,13,14] (see Fig. 5-2 [14]). 

Additionally, the initial contact or suction surface of the blade is of concern. The Elliott program indicates that erosion of the suction surface is almost nonexistent tlierefore, that erosion can be neglected in this instance. This conclusion is substantiated by actual field experience. 

He analyzed dispersion data from 11 field experiments in order to determine the form of the functions fy and f, including release height effects. Irwin (9) has used simplified expressions for these functions where both fy and /, have the form... 

Trays versus packing for fractionation can be a standoff if large numbers of tray passes are allowed for large fractionation towers by the operating company. Often, company preferences will decide. The licensor may also have preferences based on field experience. 

High Chromium Alloys. Field experience and laboratory data indicate that alloys high in chromium offer the best fuel ash corrosion resistance. The table below shows laboratory corrosion rates for engineering alloys which have been exposed to several types of vanadium-sodium fuel ash melts. 

Extensive field experience has shown the 50 Cr/50 Ni and 60 Cr/40 Ni alloys to offer the best answer to controlling fuel oil ash corrosion. Type 446 stainless steel also shows acceptable corrosion rates but must be used judiciously due to its low strength at elevated temperatures and weldability. Since components of 50 Cr/50 Ni in contact with vanadium-sodium fuel ash melts still suffer high corrosion rates, they should be designed to minimize the amount of surface area available where ash may accumulate. 

John J. France of Sulzer Chemtech USA Inc. provided expert information on troubleshooting distillation columns to the Rio Grand Chapter of AIChE. Checklists were provided for troubleshooting mechanical problems based on considerable successful field experience. This portion of the presentation is presented here with permission. 

Have you ever tried to decide which was the best article you ever read For me, the answer comes quickly. It is How to Operate an Amine Plant. by Don Ballard. This article has helped me more than any other. I have gone back to the article time after time to troubleshoot and optimize amine plants. In addition, the article has design tips and shortcut rules of thumb developed by field experience. 

Such rules of thumb resulting from field experience give me not just isolated shortcut design parameters, but a system of understanding to do the design job. What a help ... 

The critical components should be listed and checked to see that prior usage is within the range of experience. It should be determined if the impellers have been stage tested and whether this performance has been reflected in actual field experience. Prior use history of the blading geometry being proposed should be reviewed. This should include the... 

Gottzmam, C. F., and P. S. O Neill. "Field Experience with High Efficiency Heat Exchangers," paper presented at the AlChE 74th National Meeting, March 12-15, 1973. 

Supervised field experience and 8-hour supervisor training not required... 

General site workers who attend the 40-hour course must have a minimum of 3 days of supervised field experience under the direct super-... 

The primary intent of supervised field experience is for employees to be observed by the experienced person during the course of their workday to ensure that they are working safely. These 1- or 3-day observation periods allow the experienced person to observe the worker applying proper techniques and to emphasize site-specific hazards and special working conditions. The observation period includes some on-the-job training as a reinforcement of previous training received (see Figure 8-2) [1]. 

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