Polymer fiber reinforced concrete

Polymer fiber reinforced concrete or PFRC is a composite material which is used for building construction. This is a relatively new material with more efficiency, strength and is inexpensive. Nowadays it is commonly used for the repair of new and deteriorating structures. PFRC responds linear-elastically to axial stress. The response of PFRC to axial compression is dependent on the relative proportion in volume of fibers, the characteristic properties of fiber and resin and the interface bond strength. The failure of PFRC during compression is called fiber buckling. Tensile strength is a main cause of concern in PFRC and is mainly dependent on the fiber material. PFRC is durable and less corrosive. PFRC can be used in bridges, columns, in the repair of new buildings, in the repair of damaged structures, in siding, in cladding, in roofing, in flooring and in partitions. Slurry infiltrated fibrous concrete (SIFCON) is manufactured by infiltrating cement slurry into a bed of preplaced fibers. SIFCON is a high volume fibrous concrete where fiber content varies from 8% to 20%.  

Float switch

Float switches are used to maintain liquid levels in a tank. Here a pump is used which can be energized when liquid level in the tank falls and can be de-energized when liquid level in the tank rises.  For this, a sort of sensor is also required to sense the preset height. There exist two varieties here- rod type and chain type. In the rod type, a float is attached to the lower end of the rod and the rod passes through a hole of the lever. Two ends of the rod are fitted with fine stoppers which cannot pass through the hole. In the chain type, a chain rolled over a pulley is used. Here a float is kept at one end and a counter weight at the other end.

Biogas

Alternate energy sources are a major area of interest of human kind. Biogas is a fuel which is produced through anaerobic digestion of several organic wastes. The organic waste includes agricultural, animal, domestic and industrial waste. Some of the characteristics of this gas are colorless, odorless and clean burning. The main composition of this gas is methane, carbon dioxide, nitrogen, ammonia, sulfur dioxide, hydrogen sulfide and hydrogen. Rural India carries above two million biogas plants. By a process called anaerobic digestion, biogas is produced from wastes. The two main components of a biogas plant are a digester or fermentation tank and a gas holder. The two popular designs in this category are floating gas holder type biogas plant and fixed dome type biogas plant. One more design is there which is portable and is known as bag type biogas plant. Biogas is mainly used for cooking. Other uses are in lighting, operating dual-fuel engines etc. Advantages of this power source are pollution free, environment friendly; byproducts can be used for fertilization etc. The dirty smell, low production during winter, low methane content and high retention time are some disadvantages.