Processing Steps: From the description of the processing steps, some of the advantages of integrated circuits should be apparent. Each of the fabrication steps involves hundreds of complete circuits rather than an individual component or circuit. We should, therefore, be able to fabricate hundreds of complete circuits with about as much time and labor as are required to build a single transistor. The advantages of lower cost as well as the reduction of size and weight are obvious.
To simplify the description of the succeeding processing sequence, let us consider the steps required to make a small portion of the circuit—two adjacent transistors. Four layers of silicon, each with differing impurity additions, are required: a p-type substrate, an n-type collector, a p-type base, and finally an n-type emitter. The p-type substrate layer is part of the basic wafer material, as described above.See Also Campidoglio Steps:But if the rolling wheels of a tourist chariot are good, for first impressions and a chart of facts, an inquiring mind, a rugged constitution and two sound feet are the best possible supplements. A large number of the noblest and most fascinating things Rome offers are well bunched in the half mile southwest of the Piazza Venezia and many others are within easy strolling distance of the Corso. Walking is the thing, and furthermore, wheels will not climb the lofty Campidoglio Steps, nor even the Spanish Steps.
Steps can be built of a variety of materials including paving, bricks, wood and sections of tree trunk. If you have a collection of pieces of stone, all different sizes, you can use them to make crazy-paving steps (top left). If using logs, you can either cut them into disks (bottom left) or use them whole with stakes in front to keep them firm (bottom right). You can also use planks and lengths of square wood (top right); if you can find them, railroad ties make attractive steps.
On The Other Hand See Wooden Steps:Steep flights should include a handrail—at about hand height, 2%ft—on each side, which extends about 12in beyond the flight, where it might possibly be linked with existing fencing or railings for a more unified scheme. Alternatively you might prefer to build a Wall (at handrail height) at each side of the flight.
Flights comprising more than 10 steps should be broken halfway with a landing which provides a good resting place and can also break a fall. Take this into account when calculating the number of treads that you require.
The treads should slope slightly toward the front—a pitch of about lAin is adequate —so that rainwater will drain off rapidly. This is particularly important in winter, when ice could make the steps slippery and dangerous. For the same reason, choose only block treads with non-slip textured faces.
Masonry steps can appear incongruous in an informal garden and wooden steps are often more appropriate. Cut-in steps are more suitable for this type of garden, and using sawn logs as the risers is a quick and easy way to form an attractive flight.
You can also make up a single riser from two or more slimmer logs stacked on top of each other. As an alternative to using round logs you can obtain old railroad ties sold specifically for use in garden construction. Fix the railroad tiess with stakes, as for logs, to create a more formal yet still rustic flight. Turning the flight within the slope is easily done by simply fanning out the logs or ties.
When using wooden steps, be wary of the treads becoming slippery after rainfall. A good way of keeping a gripping surface is to staple chicken wire on top of the wood. Keeping the steps clear of moss and lichen will also reduce the risk of a slip.
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