School psychology—why is the profession dying?

The state of the profession is addressed as it relates to training, practice, certification, and its professional identity. It is suggested that death of the profession is imminent unless the profession is upgraded and a new image and role are surfaced. One of the problems is that since the passing of current judicial and legislative acts PL 93-380 and 94-142, the traditional role of psychologists is no longer tenable, and new ways of behaving are required which have implications for training and practice. Survival through rebirth can occur, and new directions are suggested for the profession to consider in reassessing its new and changing role.     

Determination of “average particle size” from the screen-analysis of non-uniform particulate substances

The size distribution data obtained by screen analysis of a non-uniform substance cannot be used directly in calculating the various average diameters of the material since this method of analysis gives the distribution in terms of weight rather than count. The distribution curve by weight however bears a definite relation to the regular size-frequency curve and suitable transformation equations are presented by means of which one is able to calculate the various average diameters from the parameters of the curve given by the screen analysis. The screens are calibrated in terms of the actual size of the material retained rather than the dimensions of the screen openings or an arbitrary method of calculating the “size of separation.”     

Measurement of polarization of the tyndall beam of aqueous suspensions as an aid in determining particle size

The relation between particle size and the degree of polarization of the Tyndall beam created by suspension of non-uniform particulate substances was investigated for three materials (silica, granite, and calcite) ranging in size from one to fifty microns. The degree of polarization was found to be a function of the arithmetic mean diameter of the material. The optical property of birefringence was also found to be a determining factor although its effect was not studied quantitatively. It is shown that by combining the equation expressing the relation between particle size and strength of Tyndall beam with the mathematical relation between degree of polarization and particle size, an indirect method of obtaining a complete definition of particle size is given. Particle size values calculated from observed Tyndall readings and measurements of polarization were found to be within approximately ten per cent. of observed values.     

A Look at the New Electrical Engineering Laboratory Program at the Hopkins

The undergraduate electrical engineering program at The Johns Hopkins University has undergone extensive revision. The most striking revision has been in the laboratory program. Laboratory courses which are distinct from the lecture courses have been developed. These laboratory courses embrace the fields of basic and advanced electrical measurements, transducers, passive circuits, active networks, communications, microwaves, materials, computers, servomechanisms, and energy conversion. The experiments in each one of these fields are designed to give the student insight into both the basic and advanced concepts involved. The sequence of presentation of the experiments is chosen to allow the most complete coverage of a subject as possible, based on the order in which the electrical engineering lecture courses are taken. The use of laboratory manuals, notebooks, reports, and examinations has been given careful thought and some significant ideas have been evolved with regard to their use in establishing a successful laboratory course.