Ultra-low-noise microwave amplifiers

The highlights of 20 years of maser use and development are presented. Masers discussed include cavity, traveling wave, K band, and S band. Noise temperatures measured since 1960 are summarized. Use of masers in the Deep Space Network is presented. Costs associated with the construction of masers systems are given

The Use of the Hair Hygrometer

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The Formation of Eskers

Ever since work has been in progress in glaciated regions, long, narrow, winding, steep-sided, conspicuous ridges of gravel and sand have been recognized by geologists. They are best developed and were first recognized as distinct phases of drift in Sweden, where they are called Osar. The term Osar has the priority over other terms, but in this country, probably for phonic reasons, the Irish term Esker has come into use. With apologies to Sweden, Esker will be used in the present paper. Other terms which have been applied to these ridges in various parts of the world are serpent-kames, serpentine kames, horsebacks, whalebacks, hogbacks, ridges, windrows, turnpikes, back furrows, ridge furrows, morriners, and Indian roads

Glacial drift in the Driftless Area of Northeast Iowa

https://ir.uiowa.edu/igs_ri/1001/thumbnail.jp

The Cenozoic History of the Upper Mississippi River

Changes in the course of the Mississippi River caused by successive glacial invasions are described. Recently discovered evidence is presented bearing on the establishment of the general course of the River between Iowa and Wisconsin and Iowa and Illinois in Nebraskan time. There are also some rock terraces believed to indicate the approximate depth to which the valley had been cut by Kansan time. The Illinoian history of the river and of Lake Calvin are reviewed. The details of the present course of the river involve the definition and partial subsequent removal of Wisconsin glacio-fluvial material

The Prairie du Chien - St. Peter Unconformity in Iowa

Unconformable relations between the Prairie du Chien and St. Peter formations have long been known in Minnesota, Wisconsin, Illinois and Missouri. The existence of this unconformity in Iowa, though long suspected, has never been demonstrated, or if it has been known to exist here, the fact has not been recorded. There is nothing in the reports of the State Geological Survey suggesting anything but conformable relations between the two formations

The Address of the President: Water Problems

Few truisms have wider application than familiarity breeds contempt. J\Ian takes for granted common and therefore important things such as sunshine, clouds, rain, summer heat and winter cold, the normal winds and calms, the air we breathe, soil, ordinary hills and valleys. They do not attract the attention of the general population. It is true that every twenty-four hours more than a million tons of sand, silt, mud and dissolved salts are carried in Mississippi River past the Carrollton gage at New Orleans and dumped into the Gulf of Mexico. This is too common and familiar - and important – a fact to make the front page. The man has not bitten the dog