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Construction cranes

Heat and Gas Supply and Ventilation

I’m a student of Pacific National University. I study at the Institute of Architecture and Civil Engineering. This institute was founded in January 1995 on the base of Building Faculty which is the age of the University. The first students’ enrollment was in 1958.

The Institute trains specialists for the most important fields of human activities such as construction and improvement of the environment.

There are several specialized fields at the University:

- architecture (qualification: an architect)

- architectural environment design (an architect-designer)

- industrial and civil engineering (an engineer)

- city planning construction and economy (an engineer)

- heat and gas supply and ventilation (an engineer)

- water supply and sewage system (an engineer)

- emergency defence (an engineer).

I’m a second year student. My specialty is heat and gas supply and ventilation. Housing construction is being carried on a large scale in our country today. Civil engineers provide people with all modern conveniences such as running water, gas, electricity, central heating. Engineers of my specialty are trained for providing good and safe climatic conditions of working and living.

As ecology problems are very serious nowadays engineers have to develop and research resource- and nature-saving systems, facilities and devices. They also make researches in the filed of the highly-effected heat-generating and heat-exchanging equipment development. They develop up-to-date energy-saving systems of heating, ventilation and air-conditioning, the equipment for drying and thermal treatment of various materials and products.

In order to become good specialists we study many theoretical and special subjects. Among them are: mathematics, physics, theoretical mechanics, strength of materials, drawing geometry, geodesy and others. Good knowledge of these subjects will help our graduates in their future work.

After graduating from the university, I’ll be able to work as an engineer in specialized companies which distribute, install and make system maintenance of equipment.

 

Construction cranes

Hydraulically operated construction truck crane, is a self-propelled boom crane whose distinctive features are the possibility of varying the boom radius, high maneuverability and high travelling speed. The basis of the machine is the truck carrier (steel chassis frame) with the mounted power unit, transmission and the PTO-device operating the hydraulic cycle.

The crane is provided with the front jack and outriggers for the crane stability, hoisting equipment consists of the boom, jib and hook operated by means of the main hook block, of the winch, winch rope and the drum. The boom has a telescopic design. It is provided with the job used when you need to reequip the crane for some different kinds of work.

The crane is hydraulically driven by means of hydraulic oil acting in hydrau­lic cylinders. The control of the hydraulic operations is performed by three lev­ers for slewing, raising, lowering, extending and retracting the boom. There are two cabs in the crane: one for die the carrier driver and the other for the operator.



 

Plastics

Plastics are à large and varied group of materials consisting of combinations of ñàrbîn and oxygen, hydrogen, nitrogen, and other organic and inorganic elements. While solid m. its finished state, à plastic is at some stage in its manufacture, liquid and ñàðablå of being formed into various shapes. Forming is most usually done through the application, either singly or together, of heat and pressure. There àãå over 40 different families of plastics in commercial èse today, and each màó have dozens of subtypes and variations.

À successful design in plastics is always, à compromise among highest performance,. attractive appearance, efficiell1t production, and lowest cost. Achieving the best compromise requires satisfying the mechanical requirements of the part, utilizing the most economical resin or ñîm­pound that will perform satisfactorily, and choosing à manufacturing process compatible with the part design and material choice.

Most people have now outgrown the impression that plastics àãå low-cost substitute materials. Those that still view plastics as cheap and unreliable have not kept uð with developments in polymer technology for the past ten years.

Ìànó plastics did indeed evolve as replacements for natural products such as rubber, ivory, silk îr wool, which became unavailable îr în short supply. But the new materials did not necessarily råðlàñå the older ones permanently nor made them obsolete. In mànó cases, they met àn increased demand that could not bå met bó the natural product àlînå.

Today's engineering resins and compounds serve in the most de­manding environments. Their toughness, lightness, strength, and ñîrrosion resistance have won òàïó significant applications for these materia1s in transportation, industrial and consumer products. The engineering plastics àãå now challenging the domains traditionally held bó metals: tru1y 10ad-bearing, structural parts.

 

Fibers

Fibers àãå probably the oldest engineering materials used bó màn. Jute, flax and hemp have båån used for "engineered" products such as ãîðå, cordage, nets, water hose, and containers since antiquity. Other plant an animal fibers have båån used for felts, ðàpår, brushes, and heavy structural cloth.

The fiber industry is clearly divided between natural fibers (from plant, animal, oã mineral sources) and synthetic fibers. Ìànó synthetic fibers have båån developed' specifically to replace natural fibers, because synthetics often behave mîrå predictably and àãå usually more uniform in size.

For engineering purposes, glass, metallic, and organically derived synthetic fibers àãå most signifiñànt. Nylon, for example, is used for belting, nåts, hose, rope, parachutes, webbing, ballistic cloths, and as reinforcement in tyres. .

Metal fibers àãå used in high-strength, high-temperature, light-weight composite materials for aerospace applications. Fiber composites improve the strength-to-weight ratio of base materials such as titanium and aluminum. Metal-fiber composites are used in turbine compressor blades, heavy-duty bearings, pressure vessels and spacecraft re-entry shields. Boron, ñàrbîn, graphite, and refractory oxide fibers are ñîmmîn materials used in high-strength fiber composites.

Glass fibers àãå probably the most ñîmmîï of àll synthetic engineering fibers. These fibers àãå the finest of all fibers, typically înå to four microns in diameter. Glass fibers àãå used for heat, sound, and electrical insulation; filters; reinforcements for thermoplastics and thermoset resins and for rubber (such as in tyres); fabrics, and fiber optics.


Date: 2015-12-11; view: 1102


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