Dean problem

D. THE MOTION OF A FLUID THROUGH A SLIGHTLY CURVED TUBE - THE DEAN PROBLEM... 

D. The Motion of a Fluid Through a Slightly Curved Tube - The Dean Problem... 

Problem 12-7. The Dean Problem. A problem related to the Taylor-Couette problem is the instability of pressure-gradient-driven flow in a curved channel. An example of this is the flow that is due to a pressure gradient in the azimuthal direction between curved walls that are sections of a pair of nonrotating concentric cylinders of radius R and R2, respectively. 

Bara, B., K. Nandakumar and J. H. Masliyah, An Experimental and Numerical Study of the Dean Problem Flow Development towards Two Dimensional Multiple Solutions, J. Fluid Mech., 244, 339-376 (1992). 

Pharmacoethics A Problem-Based Approach David A. Gettman and Dean Arneson... 

As already noted, the chemical composition of petroleum and petroleum products is complex and may change over time following release into the environment. These factors make it essential that the most appropriate analytical methods are selected from a comprehensive hst of methods and techniques that are used for the analysis of environmental samples (Dean, 1998 Miller, 2000 Budde, 2001 Sunahara et al., 2002 Nelson, 2003 Smith and Cresset, 2003). But once a method is selected, it may not be the ultimate answer to solving the problem of identification and, hence, behavior (Patnaik, 2004). There are a significant number of petroleum hydrocarbon-affected sites, and evaluation and remediation of these sites may be difficult because of the complexity of the issues (analytical, scientific, and regulatory not to mention economic) regarding water and soil affected. 

Gaseous sample introduction into an ICP-MS presents different problems. Owing to its extremely sensitive nature, Dean et al. [13] introduced the sample as the gaseous hydride by a flow-injection approach. This was reasonably effective because lower volumes of samples and reagents were in use. They utibzed nitric acid as a carrier stream to prevent the formation of argon chloride species in the plasma. Argon chloride has the same mass as arsenic which is mono-isotopic, and this severely bmits arsenic determination. An additional problem was that the sensitivity was extremely dependent on the purity of reagents. 

Nowadays, the concerns about pollution and the recent dramatic increase in the price of oil have definitely boosted interest in hydrogen as an energy vector and a clean fuel, although the problem of a dean energy source is still far from being solved. 

In the past, removing metal and metalloid contaminants from soil has been impossible, and site dean-up has meant excavation and disposal in a secure landfill. An exciting new approach to this problem is phytoextraction, where plants are used to extract contaminants from the soil and harvested. Immobilization and Toxicity-Minimization. 

The most common method of converting iron ore to metallic iron utilizes a blast furnace wherein the material is melted to form hot metal (pig iron). Approximately 96% of the world s iron is produced this way (see Iron). However, in the blast furnace process energy costs are relatively high, pollution problems of associated equipment are quite severe, and capital investment requirements are often prohibitively expensive. In comparison to the blast furnace method, direct reduction permits a wider choice of fuels, is environmentally dean, and requires a much lower capital investment. 

The dry powder process has several additional advantages over the wet process. For example, much less waste of enamel occurs because the dry over-spray is airborne and recyded in a dosed system. No-pickle ground coats have broadened the application of both wet-process and dry-process systems. These enamels are applied over deaned-only metal. Thus the problems of disposing of pickling acid wastes containing iron sulfates and nickd wastes are eliminated (see Metal surface treatments) (7). 

Belloto, R.J., Jr., Dean, A.M., Moustafa, M.A., Molokhia, A.M., Gouda, M.W, and Sokoloski, T.D. Statistical techniques applied to solubility predictions and pharmaceutical formulations an approach to problem solving using mixture response surface methodology). Pharm., 23, 195, 1985. 

The problem was first approached in 1954, when de la Mare pointed out a major discrepancy in the observations for the para chlorination of biphenyl in an attempted correlation based on the Hammett equation. Subsequently, Eabom and his students examined the behavior of biphenyl in several additional reactions (Deans et al., 1959 Eaborn and Taylor, 1961b) concluding that reactivity in the para position of hiphenyl did not conform to a linear free-energy relationship. Moreover, the p-phenyl group did not accelerate the substitution to the anticipated extent. The peculiar behavior of the phenyl group prompted several investigations of the substitution reactions. These data are summarized in Table 7. 

Mary Ellen Murphy, St. Joseph College I think one of the problems in academia is the fact that department chairs and deans and vice presidents and presidents very often were men, and so the woman probably didn t have much of a chance or much of a voice at the decision-making level. I think it is only more recently that you have somewhat honest search committees, if most places could even say that at this point in time. Having been a dean, I know very well that there is a tremendous prejudice—even on the part of women—that the man is probably going to be better in the stack of applications. So I think that we have to be concerned about trying to get the jobs, but I also think we have to be concerned about having women in some of these higher-level positions where the decisions are finally made. 

Peter Rabideau, Iowa State University Before moving to Iowa State, I was dean of science at Louisiana State University. I put an incredible amount of pressure on the chemistry department to look for female candidates because we had no females. I think sometimes females don t want to join departments where there are no females. For example, the chemistry department responded and invited four candidates, three of whom were females, terrific candidates. We liked them all. We made great offers to all of them, and they all turned us down. So I think there is another problem—that it is just difficult when you don t have that environment. A lot of departments find themselves in the situation and are trying to counter it. 

We asked the dean to address the problem by establishing a committee that would look into the entire matter. We wanted to document the problem for the administration, so that when a woman had a problem, instead of having to go individually and prove the case over and over, there would be a body of documentation. It would help administrators to understand the problem and help each woman to explain her own case on her own. We also wanted to look at data to see whether the perception that things were unfair was really correct. Would the data also show discrepancies in terms of things like resources and compensation Most important, we wanted to work collaboratively with MIT to study and then try to solve a problem. 

It was reported that in some schools, these problems don t exist anymore because there are very enlightened people in leadership positions—deans, department chairs, and so on—who have taken the proper steps and are addressing the situation. We should be fair and give credit where credit is due. The problems are not universal. There might be problems in some departments, but other departments are really taking the proper steps. 

Last but not least, Why is the makeup of this particular group—the workshop participants—what it is Where are the deans, where are the department chairmen, where are the decision makers A number of people said they had been sent by their dean or supervisors. But the supervisors are the ones who must take care of this problem. The question is, Why aren t those people here ... 

The experiments and the necessary theory were developed by Mohammad Abu-Hamdiyyah, Pasupati Mukerjee, and myself in connection with a related but different problem—an attempt to determine unambiguously the rate of transport of simple non-micellized detergent ions through a membrane (I, 18). We needed information about the ability of the micelles to cross the membrane, and the insoluble material was used mainly to indicate micelle behavior. The paper reporting that work (I) gives experimental details and further interpretation of the results. Since then I found that Dean and Vinograd (4) developed the qualitative aspects of this argument 25 years ago. 

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