What is a pneumatic architecture?
Pneumatic structure, Membrane structure that is stabilized by the pressure of compressed air. Air-supported structures are supported by internal air pressure. Air-inflated structures are supported by pressurized air within inflated building elements that are shaped to carry loads in a traditional manner.
What are pneumatic structures made of?
The pneumatic structures are generally made from the laminated membranes such as nylon, fibreglass polyester, silicon rubber etc. The shape of the Pneumatic structure is round because it creates a larger volume for less amount of material.
How do air-supported structures work?
An air-supported (or air-inflated) structure is any building that derives its structural integrity from the use of internal pressurized air to inflate a pliable material (i.e. structural fabric) envelope, so that air is the main support of the structure, and where access is via airlocks.
What is the membrane of a building?
Membrane structure, Structure with a thin, flexible surface (membrane) that carries loads primarily through tensile stresses. There are two main types: tent structures and pneumatic structures. The Denver International Airport (1995) features a terminal building roofed by a white membrane stretched from steel masts.
What makes a structure stable?
A structure is stable if its centre of gravity lies above its base. An object is unstable when its centre of gravity lies outside its base. In other words, an object is unstable if a line drawn between its centre of gravity and the centre of the Earth does not pass through its base.
What is a membrane structure architecture?
Membrane structures are lightweight spatial structures made of tensioned membranes. Membrane can be used to construct roofs and façades, free-standing buildings, building envelopes, skylights, indoor ceilings and/or accent enclosures.
What is the structure of a biological membrane?
Biological membranes consist of a double sheet (known as a bilayer) of lipid molecules. This structure is generally referred to as the phospholipid bilayer. In addition to the various types of lipids that occur in biological membranes, membrane proteins and sugars are also key components of the structure.
What is membrane used for in construction?
A (non-biological) membrane is a very thin, sheet-like material, such as cling film, soap film or a piece of cloth. Membranes may be used as structural components of tensile structures. A tensile structure is a structure that is stabilised by tension rather than compression.
What is a suspended structure?
building structures in which the main elements that support the load (wires, cables, chains, grids, sheet diaphragms, and so on) are subject only to forces of extension. Modern plane suspension structures are used mainly in bridges and roofs, ropeways, and overpasses for pipelines. …
What is cable structure?
Cable structure, Form of long-span structure that is subject to tension and uses suspension cables for support. The graceful curve of the huge main cables of a suspension bridge is almost a catenary, the shape assumed by any string or cable suspended freely between two points.
What is suspension cable?
[sə′spen·shən ‚kā·bəl] (engineering) A freely hanging cable; may carry mainly its own weight or a uniformly distributed load.
What is cable civil engineering?
Cables are flexible structures that support the applied transverse loads by the tensile resistance developed in its members. Cables are used in suspension bridges, tension leg offshore platforms, transmission lines, and several other engineering applications.
What is cable Theorem?
It can be stated as: “ At any point on a cable acted upon by vertical loads, the product of the horizontal component of cable tension and the vertical distance from that point to the cable chord equals the moment which would occur at that section if the loads carried by the cable were acting on an simply-supported beam …
What is the difference between cables and arches?
What is the difference between the basic action of an arch and suspension cable? An arch is essentially a compression member which can also take bending moments and shears. Bending moments and shears will be absent if the arch is parabolic and the loading uniformly distributed. A cable can take only tension.
What is the maximum sag of the cable?
The maximum sag given the maximum stress of the material is 42.26 m.
What is the formula of SAG?
w is the weight per unit length of the conductor. So, having calculated the value of x1 and x2, we can easily find out the value of sag S1 and sag S2. The above formula is used to calculate sag when the conductor is in still air and ambient temperature is normal. Hence the weight of the conductor is its own weight.
What factors affect a conductor’s sag?
Factors affecting the sag
- Conductor weight – Sag of the conductor is directly proportional to its weight.
- Span – Sag is directly proportional to the square of the span length.
- Tension -The sag is inversely proportional to the tension in the conductor.
- Wind – It increases sag in the inclined direction.
Why conductor sag should be kept minimum?
The conductor sag should be kept to a minimum in order to reduce the conductor material required and to avoid extra pole height for sufficient clearance above ground level.
Why are the transmission cables usually fixed with a sag?
The lines are often heavily loaded because of increased power consumption, and the conductors, which are generally made of copper or aluminum, expand when heated. That expansion increases the slack between transmission line structures, causing them to sag.
What is Corona in power system?
Corona Discharge (also known as the Corona Effect) is an electrical discharge caused by the ionization of a fluid such as air surrounding a conductor that is electrically charged. This is common in high voltage electric power transmission lines.
What is Corona formula?
En = 1/(√3)×line voltage. Peek’s formula is applicable for decided visual corona. This formula the gives the inaccurate result when the losses are low, and En/Eo is less than 1.8.
What is Corona power loss?
When the potential difference between two conductors of transmission line raised beyond a certain limit, at a point is reached when a violet glow appears around the conductor surface with a hissing noise and ozone gas smell this phenomenon called Corona and this causes corona power loss in the transmission line.
What causes electrical corona?
A corona discharge is an electrical discharge caused by the ionization of a fluid such as air surrounding a conductor carrying a high voltage. A corona occurs at locations where the strength of the electric field (potential gradient) around a conductor exceeds the dielectric strength of the air.
Why corona loss is less in HVDC?
All Answers (3) Because In DC field negatively charged particles move from negative pole conductor to positive pole conductor continuously and steadily. Naturally they do not tend to remain near the surface of negative pole conductor thats why corrona loss less in negative polarity HVDC homopolar line.
Why is corona discharge purple?
The bluish-purple glow that corona discharges produce is a side effect of electrons recombining with positive ions to reform neutral atoms. When atoms reform they release a photon of light. These photons ionize more atoms maintaining the corona discharge.
What are the factors which affect Corona?
Factors affecting Corona and Corona Power loss
- Line Voltage: The line voltage directly affects the corona and the corona loss.
- Atmospheric conditions: The most important atmospheric factors are temperature and pressure.
- Size of the conductor: The corona loss is directly proportional to square root of radius of conductor.
What are the methods of reducing Corona?
Corona discharge can be reduced by the following methods:
- By increasing the conductor size: As explained above, larger the diameter of the conductor, lesser the corona discharge.
- By increasing the distance between conductors: Larger the conductor spacing, lesser the corona.
What is Ferranti & corona effect?
Ferranti effect on long transmission lines at low load or no load increases the receiving end voltage. This is common in high voltage electric power transmission lines. The corona effect can also produce a violet glow, production of ozone gas around the conductor, radio interference, and electrical power loss.
What is corona effect and skin effect?
“Corona is a discharge caused by electrical over stress.” Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor.