Semi-Conductor (materials)

These are metals in which the valence band are completely filled and electrons are readily available for movement into the conduction band and creating an electron-hole pair in the structure of the material and apparent electrical conditions.

Examples of semi conductor materials are group IV elements such as carbon, silicon, germanium, tin.

Semi conductor can be classified into two forms : Intrinsic and Extrinsic semi conductor

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Construction Procedure of Surface Road Side Drainage-PART 1 (with picture)

Surface water ( i.e., rain water) that falls on the ground surface such as; open field, paved areas or road surface, roof tops etc are channeled to a main drain naturally or through a constructed channel which is referred to as drainage. Procedure for construction of a common drainage (trench) (1m x 1m U drainage) (reinforced). includes; I. Marking Of Alignment: The surveyor marked out the alignment for the trench to be dug. II. Digging/Excavation: The surveyor marked out the dept of the trench to be excavated with a mechanical excavating machine. For a 1m x 1m drainage, the mathematical process of obtaining the required dept is to sum together the dept of the required drain + base + blinding. For dept: A drain of dept1000 mm, base of 150 mm and blinding of 50 mm. Hence 1000mm + 150mm + 50mm = 1200mm (1.2 m) So an excavation of 1200mm (1.2m) is required from the to level of the road surface. For width:

Construction Procedure of Surface Road Side Drainage-PART 2 (with picture)

V. Next step is laying of concrete base on the blinded surface and the positioned reinforcement. A concrete base of 150 mm is to be laid or cast on the blinded floor, concrete grade C20 of ratio 1:2:4 is allowed (See concrete grading and mix ratio). A guiding panel is placed into position to guild in the laying of the concrete base in order to achieve a uniformly alignment base edge, thickness and width, also to manage concrete material while pouring. The base is cast with the U shape reinforcement bottom in between the concrete base achieving concrete cover below and above. VI. After setting and drying of the concrete base, next is to position the side wall panel form work. The floor base is marked to give the required one meter (1000 mm) internal width where the panel will be positioned. The panel wall spacing is 100mm, and wall height of 1000mm (1 meter), the panel is lubricated, clipped and prepared to accept the Concrete.

Setting out of a building

A building is set out in order to accurately define the outline and width of the excavation and to determine the center line of the proposed building walls, so that construction according to the building professionals drawing (the architectural plan) plan can be transfer into the ground, this building process is called setting out of building. The center line method of setting out is generally preferred and adopted Setting out can be a very complex engineering process but with need experience its quite easy. Experienced engineer and surveyors are those involved in setting out of structures, in large projects, services of land surveyors are required for more accurate transfer of levels and angles in setting out with the aid of a Theodolite to decided point around the building area But we are going to concern ourselves with the most common setting out method · Setting out using pegging · Setting out using blocks. But here, we will be discussing

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