Permeabilities to salts and water of macrocyclic polyether–polyamide membranes

The polyether–polyamide (PC-6) strongly absorbs sodium salts from their aqueous solutions. Membranes based on PC-6 and on its polymeric alloys with poly(vinylpyrrolidone) (PVP) are, however, much more permeable to water than to salts. The membrane permselectivity is due to the low mobility of the absorbed salts. Desorption experiments were conducted to determine the values of the diffusion coefficients of the sodium ions in the investigated membranes. They were found to vary from 5 × 10^-12 cm²/sec in loose PC-6 membranes to 1.7 × 10^-9 cm²/sec in the polymeric alloy containing 30% PVP. Water permeation experiments with the alloy membranes yielded values of the diffusion coefficients in the range of 2–5 × 10^-7 cm²/sec. The apparent “energy of activation of the diffusion” of sodium ions in such membranes was found to be essentially indentical (～12 kcal) with the energy of activation of the decomplexation of the sodium–“crown” complex. The ramifications of the proposed “site to site jump” diffusion mechanism were discussed. The permeability characteristics of PC-6 membranes were found to be strongly affected by their “history.”. The observed phenomenon was explained in terms of reversible changes in the structure of the polymeric network, in the presence and in the absence of the absorbed salts. It has been found that PVP has a stabilizing effect on the permeability characteristics of the membranes. Reverse osmosis experiments indicated that their intrinsic osmotic characteristics seem to be superior to those of the commercially used materials. Their salt rejections are in the range of 95–99.5%, and their permeabilities to water are at least one order of magnitude higher than those of the unmodified aromatic polyamides.     

Price Adjusted Single Sampling with Quadratic Indifference

The purpose of this paper is to expand the application of Price Adjusted Single Sampling, PASS, to include quadratic indifference. The concept of PASS is first reviewed. Secondly, the statistical background of PASS with quadratic indifference is formulated. Finally a step by step procedure for implementing a PASS plan is presented along with an example.     

Development of an elastomer with a high static or breakaway friction coefficient

This paper reviews the literature concerning the measurement of friction coefficients (μ) for elastomers and summarizes our data measured under static or breakaway conditions against epoxy painted steel using ～ 176 psi contact pressure. Although largely related to missile launch system applications, the μ values presented are specific for interface pairs, normal loading force, and speed. Therefore, this article should serve as a starting point for those requiring specific friction data for selected elastomers.     

Physical simulation: The use of scaled-down fully functional components to analyze and design automated production systems

This paper presents and discusses the physical simulation methodology currently employed in the Industrial Automation Laboratory in the Department of Industrial Engineering at Texas A&M University. Physical simulation is the study of complex automated manufacturing and material handling systems through the use of scaled-down system replicas controlled by mini and microcomputers using full-sized software. The physical simulation methodology is the design, construction, operation, and study of such systems in a laboratory environment. The methodology consists of identifying basic automated system components; constructing scaled-down, functionally-equivalent generic models of the components with mechanical breadboarding kits; and then using these generic models to construct fully functional scaled-down systems. Thus, it allows us to evaluate the dynamic physical interactions using the models to confirm design decisions and to develop and test system software in parallel with the construction of the full-sized system. This approach should allow a cost reduction in the design cycle for complex automation because (1) through it we can identify design errors early, and (2) it provides a mechanism for the parallel development of both the computer hardware/software control system and the system's machinery. The methodology is currently under development in the Industrial Automation Laboratory in the Department of Industrial Engineering at Texas A&M University.     

A factor analysis of assertive behaviors.

Factor analyzed the data from 5 objective measures of interpersonal behavior, presumed to be tapping "assertiveness," administered to 55 male alcoholic inpatients. In addition, each behavioral measure was correlated with a subjective global rating of assertiveness. Four of the behavioral measures loaded highly on a general factor of assertiveness. The fifth behavioral measure loaded highly on a separate factor, Response Latency. All behavioral measures with the exception of response latency evidenced significant correlations with the subjective rating of global assertiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Considerations of importance to decisions on an alternate nuclear program

The nuclear power program of the United States is based on the concept that nuclear plants of the thermal converter type—primarily those cooled and moderated by light water—will fill the generating needs in the early years, and that the fast breeder will be developed on a sufficiently rapid schedule to take over the major portion of the electrical load before our reserves of moderate-cost uranium are used up. In this plan the thermal converter reactors play an important, if not altogether essential, role as producers of plutonium for the initial inventory of the breeders. To reassess this plan, in the absence of any reliable model for the long-term U.S. economy in its relationship to energy supplies and costs, we are forced to use as input some estimate of the energy demand over a period of approximately a century. This input has a profound impact on the assessment, affecting not only our estimate of the urgency of development of the breeder, but conclusions as to optimum choice of converter reactors as well. Inasmuch as the demand is not an independent variable, but will surely depend upon the cost of power, this approach has obvious deficiencies.Since, however, the objective of planning is to make things happen as one wants them to—and what we are doing here is planning—I believe we should concentrate on making available the desirable quantities of electrical energy, rather than some smaller amounts which may indeed fill the demand if our plans go awry and the power cost rises drastically.I have therefore chosen a relatively generous demand projection, which amounts to 18.3 × 10⁷ MW-yr of total electrical energy over the next century, of which it is assumed that 70% will be generated by nuclear fission. In view of the great uncertainty of projection, a simple linear growth has been assumed.When one assesses the options for the future in terms of large energy productions, it is necessary to consider separately the case in which no fast breeder is assumed to be developed and the case in which it is assumed that the fast breeder is developed to a viable commercial stage, but possibly on a delayed schedule. In the former case the important performance characteristic of the nuclear plant is the amount of energy produced per unit of natural uranium fed into the system. In the latter case one must consider the production of plutonium for the fast breeder inventory. The important characteristic then becomes the amount of net plutonium produced per unit of natural uranium fed to the system. If the growth rate of breeder capacity is limited by plutonium availability, the efficiency of use of feed uranium, in terms of energy production, has little effect on the total quantity of natural uranium required.The minimum mission for fission power plants is assumed to be the supply of 70% of the total electrical demand over the next century, a period which might be a reasonable one for the development and large scale production of some alternate energy producer. If the light water nuclear plants produced all of this energy (13 × 10⁷ MW-yr) they would require some 25 million tons of natural U₃O₈: more than our estimated resources, even including those in the cost range of $100/lb. It is concluded that, in the absence of the fast breeder, an acceptable alternative would be a reactor whose power cost sensitivity to the price of natural U₃O₈ would be less than that of the light water reactor, by something like a factor of four.If we seek, not to replace the breeder in our plan, but to find some better converter than the LWR in the interim before its large-scale production, the considerations become more complex. For minimum long-term resource requirement we must provide first for plutonium production, up to the point that plutonium availability is never a limit to breeder growth. Up to that point, the building of plants which use up natural uranium without producing net plutonium can only increase the long-term consumption of uranium, regardless of how efficient they are in producing energy. I refer you to Fig. 3 for an illustrative set of curves which show typical characteristics of a converter-breeder system in which the early growth of breeder capacity is plutonium-limited.The optimum converter mix then depends on a number of considerations which we are unlikely to predict with any accuracy: the electrical demand curve, the development schedule of the breeder, the limitations other than plutonium availability to the rate of construction of breeders, and the breeding and inventory characteristics of the breeder. From the point of view of resource conservation alone, however, we cannot go wrong with an improved converter which can be made either an efficient energy producer or an efficient producer of plutonium, simply by changing its fuel cycle. This of course suggests the heavy water reactor.From the more practical point of view we must recognize that any decision to introduce a new converter type in the United States could slow down the development of the fast breeder, not only by diverting development and production resources, but also by appearing to reduce the urgency of that development. In the long run this might overbalance any direct benefit from the alternate converter type. I believe the one thing that can be shown by analysis is that the most effective way of conserving nuclear resources is to develop, introduce, and build the fast breeder as rapidly as possible. My own opinion is that the real incentive for looking at alternates is to provide some kind of a backup against the possibility, which I hope is a very remote one, that the fast breeder development may be stopped or severely delayed for non-technical reasons.     

Solution of transient temperature fields in laminated anisotropic slabs and cylinders

Solutions are developed for the transient temperature fields of infinite laminated composite slabs and cylinders composed of any number of distinct lamina each with its own fully populated conductivity tensor and heat source. The external and interlamina conditions treated consist of the most general nonhomogeneous form. Through the use of complex Fourier series, the governing equations are reduced to a modified version of the Vodicka-Tittle problem. Since the transformed equations for a given lamina are nonself-adjoint, using the conjugate properties of the entire set, a complex version of the Vodicka-Tittle procedure is developed the use of which yields the requisite solution. For several forms of monoclinic material types, the infinite restrictions imposed on the fully anisotropic set are lifted through the use of various finite transforms. Due to the generality of the solutions developed, the results of several authors are contained as special cases.     

What is learned during automatization? The role of attention in constructing an instance.

[Correction Notice: An erratum for this article was reported in Vol 20(6) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2008-10475-001). In the aforementioned article, the Appendix on page 1050 was incomplete. The complete Appendix is presented in the erratum.] Seven experiments with 372 Ss were conducted to examine the role of attention in automatization. Ss searched 2-word displays for members of a target category in divided-attention, focused-attention, and dual-task conditions. The main issue was whether attention conditions would affect what Ss learned about co-occurrences of the words in the displays. The attention hypothesis, derived from the instance theory of automaticity, predicts learning of co-occurrences in divided-attention and dual-task conditions in which Ss attend to both words but not in focused-attention conditions in which Ss only attend to 1 word. The data supported the attention hypothesis and therefore the instance theory. [A correction concerning this article appears in Journal of Experimental Psychology: Learning, Memory & Cognition, 1994(Nov), Vol 20(6), 1390. The Appendix was incomplete and the complete Appendix is presented.] (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship of sexual mixing across age and ethnic groups to herpes simplex virus-2 among unmarried heterosexual adults with multiple sexual partners.

Sexual mixing is important to understanding how sexually transmitted diseases (STDs) spread in the general population, and, identifying people who mix across social groups aids HIV-STD prevention. The authors examined (a) the extent to which people have sexual partners from other sexual networks (disassortative mixing) in a probability sample of unmarried heterosexual adults reporting multiple sexual partners (N?=?545) and (b) the relationship between mixing and Herpes Simplex Virus-2 (HSV-2). After demographic variables and number of lifetime sexual partners were controlled for, heavy mixers were significantly more likely to be HSV-2 positive. Degree of mixing down produced the most powerful relationship to HSV-2. Age, education, ethnicity, and a history of incarceration or IV drug use were found to distinguish between light and heavy mixers, although differences between ethnic and age mixing were observed. The results have implications for understanding HIV-STD transmission and for directing interventions toward population segments at high risk for transmitting HIV-STDs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Applications of nonlinear finite element method to contact problems and paper handling problems

A model that predicts the paper behavior during the printing process at various time intervals is proposed. The tendency of wrinkling can therefore be observed. This model will accommodate any paper topology induced by moisture effects or otherwise, and can analyze virtually any roll geometry and roll combinations.Nonlinear Finite Element Method is applied to the contact problem of two layered cylinders compressing a paper with arbitrary initial shape. The analysis assumed plane strain condition, the paper can therefore be treated as a beam. The result from the contact problem is applied to predict the behavior of the paper as it is feeding through the roll system. The Total Lagrange Formulation with Piola-Kirchoff Stress and Green-Lagrange strained is used. The quasi-static solution at different time intervals is presented. It was found that they agreed favorably with experiments.