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Civil Engineering
Civil Engineering is a profession of designing and executing structural works that serve the general public, like houses, buildings, roads, etc. A Civil Engineer is an engineer trained in the design and construction of public works, such as bridges or dams, and other large facilities.
4,921 Questions
What is reinforce concrete t-beam?
It is a monolythic concrete beam consisting of a web and a flange to form the shape of a"T" .
The term "key plan" is used in civil engineering projects to describe a feature depicted on the construction plans of large and often complex projects. The overall project is first shown in one or more overall views drawn in large scale showing the region or vicinity in which the project is built. These overall regional plans are then followed by multiple detailed views of the project depicted in larger scales and finer detail. Ofterntimes, however, when you are reviewing the finer points on a detailed drawing, it is easy to loose track of where you are in the overall project. Thus, the designer often includes a small "key plan" located in the corner of the sheet you are viewing that shows the location of that detail sheet to the much larger project. As an example, say we are designing an oil refinery. On the overall title sheet, we often show a vicinity map that shows the refinery in relation to major highways and access roads so you can at least figure out how to get there. The next plan will often be an overll plan view of the refinery at a scale of something like 1" =200'. It would show the property lines of the refinery, access points via road and railway, where the incoming pipelines are, and any zoing setbacks that show the relationship of the plant to neighboring properties. A general, non-detailed outline of the refinery and storage tanks might also be shown....but not in a lot of detail. On the following pages, we would typically draw detailed site maps of the refinery at a much larger scale, such as 1"=50'. It might take 10 or 15 of these sheets showing all the features of the refinery with much more detail and more complete labelling of the features. On the lower right corner of each drawing near the titleblock we would include a small "key plan" that would show a sketch of the overall refinery, and where in the refinery the page we are looking at occurs. For many projects, we would want to show detailed piping and electrical concuit drawings at an even larger scale, such as 3/8"=1'. In every case, we would want to show coordinates on the drawing so each feature can be located within the plant site, and in the corner of each plan view, we would include a "key plan" so the reader can locate the sheet in relationship to the overall refinery. Key plans are not limited to refineries or oil & gas work. Basically, for any civil engineering project that is large and complex, it is a way to protray the overall project on multiple plan drawings at multiple scales, and yet provide the reader with a quick way to orient him or herself within the overal project.
Probably the easiest of thermodynamic problems to solve, as this one only requires the use of steam tables and interpolation to solve. Entropy (s) at 4 MPa and 300 C = 6.3639 kJ/kg*K. Now use the steam tables at 9 MPa and s = 6.3639 kJ/kg.
At 9 MPa and 400 C s = 6.2876, and at 450 C s = 6.4872. So the correct temperature falls between the two values. Using linear interpolation, we find that the correct temperature is approximately 419 C.
What is the definition of a shell structure?
A shell is a building that is empty in the inside. Typically a shell permit is obtained for a commercial/retail property that does not have a Tenant. The owner will fill this empty space and then a Tenant Improvement (TI) Permit is obtained.
The shell permit would include only the most basic structure the code will allow. The main shape of the building, exiting, egress lighting (exit lighting), the minimum number of restrooms required. The shell permit does not include occupancy. A Tenant can not move in until they obtain a Tenant Improvement Permit.
If a restaurant moved in and wanted a Tenant Improvement they would provide drawings for all seating, kitchens, lighting, mechanical, electrical, plumbing for ONLY the portion that the restaurant...the rest of the structure remains unoccupied until a TI Permit is obtained
What are difference between grade a b and c material?
The main difference is in between grade A,B & C IS THE CARBON CONTAIN OF THE MATERIALS.
"A plat" and "to plat" are words referring to the intertwining of cords (usually hair) so that they form a single rope. The intertwining is by crossing the cords over one another to form a braid, not by twisting.
What is low profile air conditioner?
Hard to believe there are people so ignorant that this question was even asked! A "low profile" air conditioner is one that takes up a smaller amount of window space, as compared with "traditional" air conditioners. It is best on smaller windows, or where you want to maximize the view out of a regular window. Do a search of "LG GL6000ER" for an example.
Why are plumbing valve rough in's standardized?
There are standards in heights of fixtures like tubs or showers. It is easier to have all valves at the same height than all over the place on walls.
Why does Tokyo Japan have a bridge called the Rainbow Bridge?
The towers supporting the Rainbow Bridge are white in color, designed to harmonize with the skyline of central Tokyo seen from Odaiba. There are lamps placed on the wires supporting the bridge, which are illuminated into three different colors, red, white and green every night using solar energy obtained during the day. See Sources and related links for a photo.
How many exits in an electrical room with a 480volt 1200amp service?
Per NEC 110.26, two exits are required unless: 1) the working clearance is double what is required, or 2) there is a "continuous and unobstructed way of exit or travel"
How can you make portland cement as quick setting and water resistance cement?
Please note that a key correction in terminology is essential before your question can be answered: use the word "concrete" instead of "cement."
The answer is to modify your mix (i.e. Portland cement, sand, gravel, and water) by using hydraulic cement to repace part of the Portland cement. The higher the amount of hydraulic cement you add, the quicker the setting time and the impermeability. However, hydraulic cement sets so quickly that you have limit the amount of total mix so as to be able to pour it and form it before it sets.
An open circuit exists when the path for electron flow is interrupted.
Sometimes this is part of the circuit design; e.g., a switch to turn a light on or off.
Open circuits may also be created unintentionally when a component part of the circuit fails so that it can no longer conduct electrons. A break in the wire connecting components, or a loose connection between wires, or even a broken filament in an incandescent bulb, for example.
Electronic circuits may contain components (resistors, capacitors, or integrated circuits, for example) which can fail in a way that creates a break in the electron path.
Particularly in an electronic circuit, it's important to be sure that the circuit is actually broken, and not simply shorted to ground. In a truly open circuit, there is no current flow. In a shorted circuit, current may be flowing in part of the circuit, but not through the whole circuit.
What causes the oxide scale on metal during heat treatment or annealing?
chemical reaction between the oygen atoms and the carbon atoms
It is rcc structure which carries the load of super structure to the soil.
Why bridges are constructed at night?
There are less people around so less traffic and confusion, and less risk of accidents; if it is an addition to a bridge less people means they can use up all the space they would like.
How much does a Herrenknecht Tunnel Boring MACHINE cost?
The largest ones go for up to $45 million brand new
What are different methods of wood seasoning?
Broadly, there are two methods by which timber can be dried: (i) natural drying or air drying, and (ii) artificial drying.
[edit] Air dryingAir drying is the drying of timber by exposing it to the air. The technique of air drying consists mainly of making a stack of sawn timber (with the layers of boards separated by stickers) on raised foundations, in a clean, cool, dry and shady place. Rate of drying largely depends on climatic conditions, and on the air movement (exposure to the wind). For successful air drying, a continuous and uniform flow of air throughout the pile of the timber needs to be arranged (Desch and Dinwoodie, 1996). The rate of loss of moisture can be controlled by coating the planks with any substance that is relatively impermeable to moisture; ordinary mineral oil is usually quite effective. Coating the ends of logs with oil or thick paint, improves their quality upon drying. Wrapping planks or logs in materials which will allow some movement of moisture, generally works very well provided the wood is first treated against fungal infection by coating in petrol/gasoline or oil. Mineral oil will generally not soak in more than 1-2 mm below the surface and is easily removed by planing when the timber is suitably dry. [edit] Kiln dryingThe process of kiln drying consists basically of introducing heat. This may be directly, using natural gas and/or electricity or indirectly, through steam-heated heat exchangers, although solar energy is also possible. In the process, deliberate control of temperature, relative humidity and air circulation is provided to give conditions at various stages (moisture contents or times) of drying the timber to achieve effective drying. For this purpose, the timber is stacked in chambers, called wood drying kilns, which are fitted with equipment for manipulation and control of the temperature and the relative humidity of the drying air and its circulation rate through the timber stack (Walker et al., 1993; Desch and Dinwoodie, 1996).Kiln drying provides a means of overcoming the limitations imposed by erratic weather conditions. In kiln drying as in air drying, unsaturated air is used as the drying medium. Almost all commercial timbers of the world are dried in industrial kilns. A comparison of air drying, conventional kiln and solar drying is given below:
- Timber can be dried to any desired low moisture content by conventional or solar kiln drying, but in air drying, moisture contents of less than 18% are difficult to attain for most locations.
- The drying times are considerably less in conventional kiln drying than in solar kiln drying, followed by air drying.
- This means that if capital outlay is involved, this capital is just sitting there for a longer time when air drying is used. On the other hand, installing an industrial kiln, to say nothing of maintenance and operation, is expensive.
- In addition, wood that is being air dried takes up space, which could also cost money.
- In air drying, there is little control over the drying elements, so drying degrade cannot be controlled.
- The temperatures employed in kiln drying typically kill all the fungi and insects in the wood if a maximum dry-bulb temperature of above 60 °C is used for the drying schedule. This is not guaranteed in air drying.
- If air drying is done improperly (exposed to the sun), the rate of drying may be overly rapid in the dry summer months, causing cracking and splitting, and too slow during the cold winter months.
The significant advantages of conventional kiln drying include higher throughput and better control of the final moisture content. Conventional kiln and solar drying both enable wood to be dried to any moisture content regardless of weather conditions. For most large-scale drying operations solar and conventional kiln drying are more efficient than air drying.
Compartment-type kilns are most commonly used in timber companies. A compartment kiln is filled with a static batch of timber through which air is circulated. In these types of kiln, the timber remains stationary. The drying conditions are successively varied from time to time in such a way that the kilns provide control over the entire charge of timber being dried. This drying method is well suited to the needs of timber companies, which have to dry timbers of varied species and thickness, including refractory hardwoods that are more liable than other species to check and split.
The main elements of kiln drying are described below: a) Construction materials: The kiln chambers are generally built of brick masonry, or hollow cement-concrete slabs. Sheet metal or prefabricated aluminum in a double-walled construction with sandwiched thermal insulation, such as glass wool or polyurethane foams, are materials that are also used in some modern kilns. Some of the elements used in kiln construction. However, brick masonry chambers, with lime and (mortar) plaster on the inside and painted with impermeable coatings, are used widely and have been found to be satisfactory for many applications. b) Heating: Heating is usually carried out by steam heat exchangers and pipes of various configurations (e.g. plain, or finned (transverse or longitudinal) tubes) or by large flue pipes through which hot gases from a wood burning furnace are passed. Only occasionally is electricity or gas employed for heating. c) Humidification: Humidification is commonly accomplished by introducing live steam into the kiln through a steam spray pipe. In order to limit and control the humidity of the air when large quantities of moisture are being rapidly evaporated from the timber, there is normally a provision for ventilation of the chamber in all types of kilns. d) Air circulation: Air circulation is the means for carrying the heat to and the moisture away from all parts of a load. Forced circulation kilns are most common, where the air is circulated by means of fans or blowers, which may be installed outside the kiln chamber (external fan kiln) or inside it (internal fan kiln). Throughout the process, it is necessary to keep close control of the moisture content using a moisture meter system in order to reduce over-drying and allow operators to know when to pull the charge.[2] Preferably, this in-kiln moisture meter will have an auto-shutoff feature.
