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A number of materials with essentially ionic binding exhibit a transition in the solid state to a high conductivity state which has been identified with positional disorder of one of the ionic species. In this paper the contrasting roles of the disorder dependence of energy and entropy in determining the nature of the transition are examined within the mean field approximation at high point defect concentration. A generalization of the Mott-Littleton defect theory is used to illustrate the role of various physical characteristics such as polarizability, elastic properties, etc., and two types of phenomenological description of the transition are discussed. [ABSTRACT FROM AUTHOR]

A method for measuring the deuterium-hydrogen-exchange accessibility of cellulose and of chemically modified cellu luloses, based on the use of D218O and mass spectroscopy, has been applied to a variety of well characterized samples. The expected correlation of the values obtained with moisture regain determined at 65% relative humidity and 21° was found for unsubstituted celluloses, but not for substituted celluloses having covalently attached oxymethylene groups. It is postulated that this lack of correlation for the substituted celluloses is due to association of water with the oxymethylene groups, thus leading to higher moisture regain values than predicted from the deuterium-hydrogen-exchange values. A good correlation, however, was found between the deuterium accessibility of these substituted samples and their alkali centrifuge values. The effect on deuterium accessibility of heating purified cotton cellulose with D218O in sealed capillary tubes was also investigated. [ABSTRACT FROM PUBLISHER]

Transmission electron microscope studies of the surface of air-corona and air-chlorine corona treated cotton fibers reveal essentially no topographical changes. Air-chlorine coronas apparently modify the wax, causing increased wettability, and C-chlorination occurs in about one of every three carbon atoms in the cuticle. About one half of the chlorine that reacts with cotton is covalently bonded to carbon in the wax, the remainder to nonextractable constituents of the cuticle or the primary wall. The secondary wall remains essentially unchanged by corona treatment as indicated by tenacity, crystallinity, solubility in cupriethylenediamine hydroxide, iodine uptake, and moisture regain (the latter may be marginally decreased). Increased accessibility of the fiber interior or secondary wall component to swelling reagents such as caustic, and yarn setting reagents such as benzyltrimethylammonium hydroxide, indicates that corona treatments modify the surface layer or primary wall in such a way as to weaken it and possibly to increase its permeability. However, marginally diminished regain and unchanged iodine sorption values do not support such conclusions. Corona treated cotton exposed to an electron beam develops cracks several thousands of angstroms deep, parallel to the spiral ridges— further evidence of a weakened surface layer. Potential practical applications of corona treatmemt are indicated by improved mercerization, better yarn stretch and setting properties, increased dyeability, and the localized heating indicated by the generation of free radicals which may make possible heat-induced localized polymerization. [ABSTRACT FROM PUBLISHER]

An inhibition of root growth, a decrease in the amount of potassium (as Rb) and phosphate (P) accumulation by the root, and a partial depolarization of transmembrane electropotential were observed to develop with a similar time course and to a similar extent when intact maize ( Zea mays L.) roots were treated with 10 M abscisic acid (ABA). Potassium uptake was inhibited by ABA when excised, low-salt roots were bathed in KCl, KHPO, or KSO. ABA did not affect the ATP content of the tissues, the activity of isolated mitochondria, nor the activity of microsomal K-stimulated ATPases. [ABSTRACT FROM AUTHOR]

The article cites a study, which is concerned with teacher's attitudinal changes due to participation in a specific Institute of the United States. As stated above in the 1967, an Institute was held at Wellesley College, Wellesley, Massachusetts to prepare a group of high school teachers to teach a new physics course. It was an effort to familiarize these teachers with the philosophy of the course and to acquaint them with the course materials and also to provide them with additional background in physics and in the history and philosophy of science. This study was designed to determine whether as a result of participation in the institute the teachers' attitudes towards physics and towards several activities related to the teaching of physics had changed. The attitude-measuring instrument was administered to the experimental teachers at the end of the fifth week of the institute. The sample consisted of 56 physics teachers selected randomly from a national population of approximately 17,000 teachers of physics. The statistical design used in this study is a one-way multivariate analysis of variance. The results of this study indicate generally favorable attitudes of teachers who attended the Institute as compared with the control teachers.

The article discusses the effects of teaching a new physics course on the attitude of teachers. This study was aimed to determine whether the teachers' attitudes changed while teaching the new course discussed in this study. As mentioned in the initial part of this study a group of 36 teachers attended an institute in preparation for teaching a new high school physics course in 1967. For this study thirty six teachers selected from a list of about 17,000 teachers of physics in the United States attended the institute. The attitude test was administered to these teachers in August during the fifth week of the institute. The same instrument was administered to 32 of these teachers in the middle of the February of the following year. These retested teachers constituted the sample for this study. Attitude was measured with an instrument adapted from Osgood's semantic differential technique. The statistical design used in this study was one-way multivariate analysis of variance. The results of this study indicated that the null hypothesis of no overall teacher attitude change towards the student activity variables was rejected.

The discovery of immense organic clouds of gas embedded in the dusty regions of our Galaxy is of tremendous importance to the origin of life. It is within these clouds that the formation of stars and planetary systems is believed to take place. The collapse of these clouds to form stars takes place in a very small fraction of the astronomical lifetime of a star. It is precisely at this moment that the clouds of organic molecules appear. [ABSTRACT FROM AUTHOR]

Methods for the determination of acid, ester, hydroxyl, and ketone (or aldehyde) groups and of mean molecular weights of small samples of natural waxes are reported. Complete analyses can be made on 0.5 g. of sample. A simplified procedure for quantitative separation of acid and unsaponifiable fractions of a wax is also reported. Molecular distillations of beeswax, caranda wax, crude and refined candelilla wax, and ouricury wax, have fractionated these complex mixtures into simpler ones. Hydrocarbons and free unsubstituted alcohols and acids, if present, distil readily at 150°C. A pot still suitable for convenient molecular distillation of up to 100-g. charges of waxes or other high melting materials is described. A method for the calculation of composition of unhydrolyzed waxes based upon function group analysis of molecular distillation fractions is described. Results of application of this method to the waxes distilled are reported and show the ubiquitousness of hydroxy acids. All of the above waxes and carnauba wax contain major proportions of esters of the hydroxy acids, and none contains as much as one-half simple esters of unsubstituted acids and alcohols. [ABSTRACT FROM AUTHOR]

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