Major Engineering Problems Research Articles

Personal radio antennas

The trend toward personalizing vehicular radio sets has been accompanied by major engineering problems. Of these, one of the most challenging is that of designing an efficient antenna to occupy a small space. Due to these size limitations, personal radio antennas will be referred to as small antennas. This paper will describe a series of tests made under laboratory conditions followed by a coverage study made under service conditions in city streets to evaluate the relative performance of small antennas and accumulate propagation data for system design. The laboratory measurements included a study of the properties of ferrite loop antennas, coils, whips and short wire antennas. The field measurements covered actual recorded field strength data from personal carried transmitters using reference quarter-wave whips. It was concluded that ¾-wave whips even when working against as poor a ground plane as the set chassis offered the best performance. However, the 20 to 25 db of shadow loss found in city streets plus a 10 to 15 db antenna loss even with whips will severely restrict the coverage of personal transmitters. Other steps may be necessary if adequate areas are to be reliably covered.

FRETTING

Fretting is productive of two major engineering problems: one is localized wear and the other, often very much more serious, a marked decrease in the fatigue-resistance of components which are or have been subject to its insidious attack.

Writing Engineering Specifications – For Quality, Not Price

One of the major engineering problems in public works is specification writing. Too often stress is placed on price than on quality. There is a definite tendency to improve specifications so that quality is foremost and price is hindmost.

VARIATION IN GREAT LAKES LEVELS IN RELATION TO ENGINEERING PROBLEMS

Throughout the recorded history of the Great Lakes, the fluctuation in their water levels has created engineering problems generally unique in relation to coastal engineering. In periods of low water, demands are heard from navigation and power interests to raise the levels. In periods of high water appeals are made by shore property owners to lower the levels. Such conflicting interests present major engineering problems, the nature of which during a given period of time reflect the long-range upward and downward trend in lake levels due to natural phenomena.

Analysis of transient voltases in networks

IMPORTANT contributions on transient phenomena have appeared in the technical literature during the past two decades. Circuit analysis has contributed materially to the present-day knowledge resulting from studies of the following major engineering problems: <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1–6</sup> transient voltages in transformer, generator, and other apparatus windings due to surges originating from lightning; traveling waves and switching phenomena on lines and cables; recovery voltages across terminals of circuit breakers and protective devices as affected by the circuit; response of devices and circuits in measuring voltages and currents applied in impulse and short-circuit testing; and others.

Major Engineering Problems: Colorado River Development

The Colorado River is one of our great national resources. It drains an area of two hundred and forty-four thousand square miles, one-thirteenth of the area of the United States south of the Canadian boundary. It comprises within its basin parts of seven states and of the Republic of Mexico. Its development is, therefore, a matter not only of interstate but of international concern. The navigability of the stream, while of little practical value at present, has been recognized by treaty, and the large areas of desert public land which can be irrigated from its surplus waters add features of national interest. Taken singly or together, such are the magnitude and scope of the problems involved that they challenge the best efforts of the engineer and the states-