Most of the procedures and techniques described were developed over the past three years. Starting in late 1976, development began on high-accuracy computer codes for electromagnetic field and force analysis. This effort resulted in completion of a family of computer programs called MAGIC (MAGnetic Integration Calcaultion). Included in this group of programs is a post-processor called POSTMAGIC that links MAGIC to GDSAP (General Dynamics Structural Analysis Program) by automatically transferring force data. Integrating these computer programs afforded us the capability to readily analyze several different conditions that are anticipated to occur during tokamak operation. During 1977 we initiated the development of the CONVERT program that effectively links our THERMAL ANALYZER program to GDSAP by automatically transferring temperature data. The CONVERT program allowed us the capability to readily predict thermal stresses at several different time phases during the computer-simulated cooldown and warmup cycle. This feature aided us in determining the most crucial time phases and to adjust recommended operating procedure to minimize risk.

Soil accumulation has been the most significant factor in the degradation of the output of photovoltaic modules used in experimental solar power generating systems. One method of measuring dirt accumulation and the subsequent power loss is to return photovoltaic modules to the laboratory for thorough examination. The use of a Glossmeter as a practical alternative to laboratory examination in making quantitative measurements of dirt accumulation on PV modules is described. Of particular value for in-situ measurements, this instrument has been used successfully to monitor dirt build-up on the front surfaces of several types of modules before and after cleaning. Surface gloss has been correlated with peak power and short-circuit current. It has also been used as an indication of the extent of dirt accumulation and the effectiveness of a cleaning process. Data obtained from Glossmeter readings taken on photovoltaic modules with over a year's exposure at photovoltaic field test sites in Nebraska; New York City; and MIT, Cambridge, are presented.

The natures of compressional (P) waves that originate in the crust, propagate in the crust and upper mantle, and are observed as Pg, Pn, and anti P waves at regional distances are examined. The discussion includes the observed variations of amplitude with epicentral distance for these waves as well as an estimate of values for the specific dissipation function Q/sub ..cap alpha../ in different regions. Studies were made on theoretical source and propagation functions for direct, reflected, and head waves as approximations for the observed Pg, anti P, and Pn, respectively. It was concluded that the classical (critically refracted) head wave is not very significant in regional observations, and that the related interference head wave and diving wave are more likely observed as Pn. Using an assumed seismic noise spectrum and the constant Q/sub ..cap alpha../ model for seismic attenuation, relations were derived for the frequencies corresponding to maximum signal-to-noise ratio for the classical and interference head waves and for the direct, reflected, and diving waves. The relations among seismic frequency, epicentral distance, anelastic attenuation, and explosion yield are illustrated for a simple source and propagation model.

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