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النص الكامل
ABSTRACT
New technology is sometimes old technology, resurrected because better technology of materials or manufacture is available that was not there in years past. Examples of this phenomenon are illustrated with four supposedly modern innovations that actually were sold decades ago.
INTRODUCTION
Modem engineers are proud of modern technology, but is it all so new? We often "re-invent the wheel" either knowingly or unknowingly. Our predecessors may have had a good idea only to find that the technology or manufacturing capability of their day was not up to the task of actual production and use. Our modern processes often provide a means to use an old idea today. Or sometimes we have what we think is a new idea until a historian points out that the "new" is actually old, having been used for a time a century ago and then forgotten after the idea fell out of favor. It has been said that those who fail to learn from history are doomed to repeat its mistakes. Perhaps this applies to successes as well. We can learn a lot from our technological forebears, including the discovery of old ideas that are were good then and even better now! Here are some examples.
FILLING HOLES IN REFRIGERATORS
Refrigerators and coolers require a cooling system, and this means an evaporating and condensing section must be located and connected together. In the case of self-contained equipment, the condensing unit is usually located either under or on top of the refrigerator. It is a separate component that is connected by wiring and tubing to the evaporator and thermostat inside. This arrangement complicates the inevitable service required and requires assembly and routing of the components in assembly. Wouldn't it be simpler and less costly to mount all the electrical and refrigeration components on a compact frame of some sort that could be simply attached to the refrigerator box and plugged in? That's what today's manufacturers think. Here's what the ad says: "we saw a hole, so we filled it... for simplicity and reliability in a refrigeration system .. .a small yet powerful unit that combines evaporator and condenser into one small, self-contained package ... preassembled so installation is a snap" (Figure 1 ).
The trouble is, it's not a...