Description : Sometimes water is sprayed during coal charging in the coke oven, which helps in (A) Prevention of clinker formation in the oven (B) Controlling the dust nuisance while charging the coal (C) Reducing the cracking of hydrocarbons in ... represented by C + H2O = CO + H2 ) (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : The reason for excessive clinker formation in gas producers is the (A) Use of coal/coke containing a high % of fines and ash (B) Use of fuel having too low an ash fusion temperature (C) Development of hot spots in the fuel bed and an abnormally high rate of gasification (D) All (A), (B) and (C)
Description : Bog iron used for the adsorption of H2S from coke oven gas is (A) An intimate mixture of saw dust and iron dust (i.e. moist ferric hydroxide) (B) Iron impregnated with resin (usually Bakelite) (C) Carbon free iron (D) None of these
Last Answer : (A) An intimate mixture of saw dust and iron dust (i.e. moist ferric hydroxide)
Description : Petroleum coke is used mainly in the (A) Discoloration of yellow glycerine (B) Sugar refining (C) Manufacture of carbon electrode (D) Blast furnace for reduction of iron ore
Last Answer : (C) Manufacture of carbon electrode
Description : High ash containing coke (A) Produces more slag when used in the blast furnace (B) Has poor strength and abrasion resistance (C) Is desirable in producer gas manufacture (D) None of these
Last Answer : (A) Produces more slag when used in the blast furnace
Description : Heating of coke, sand & phosphate rock in an electric furnace is done for the manufacture of (A) Phosphoric acid (B) Superphosphate (C) Phosphorous (D) Triple superphosphate
Last Answer : (C) Phosphorous
Description : Limestone is added in the blast furnace (during pig iron manufacture) to (A) Form slag by combining with impurities (B) Supply heat by undergoing exothermic reaction with impurities (C) Reduce the coke consumption (D) Reduce slag viscosity
Last Answer : Option A
Description : In producer gas making furnace, steam is added along with air to mainly control the (A) Fusion of coal ash & clinker formation (B) C. V. of producer gas (C) Temperature of producer gas (D) Tar content in producer gas
Last Answer : (A) Fusion of coal ash & clinker formation
Description : Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the (A) ... chamber (B) Risk of explosion (C) Chances of clinker formation (D) Incomplete combustion of coal
Last Answer : (B) Risk of explosion
Description : Which of the following must be stored in silos and not in open yard? (A) Coke breeze (B) High V.M. bituminous coal (C) Sand (D) None of these
Last Answer : (B) High V.M. bituminous coal
Description : Absorptivity of a perfect black body is unity. Which of the following has maximum absorptivity? (A) Aluminium foil (B) Refractory bricks (C) Iron plate (D) Coke breeze
Last Answer : (D) Coke breeze
Description : Which of the following is not a manufactured fuel? (A) Coke breeze (B) Soft coke (C) Colloidal fuels (D) Charcoal
Last Answer : (A) Coke breeze
Description : Which of the following would require least amount of secondary air for combustion? (A) Coke breeze containing 25% ash and 2% volatile matter (B) Anthracite containing 10% volatile matter and 8% ash ... ash and 25% volatile matter (D) Semi-bituminous coal containing 25% ash and 20% volatile matter
Last Answer : (A) Coke breeze containing 25% ash and 2% volatile matter
Description : __________ is used as a flux in the smelting of copper ore like chalcopyrite. (A) Coke breeze (B) Lime powder (C) Silica/quartz (D) Dolomite
Last Answer : (C) Silica/quartz
Description : (1) Calcium silicate and calcium alurninate Explanation: Portland cement is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco ... limited amount of calcium sulfate (which controls the set time) and up to 5% minor constituents.
Last Answer : Milk is a colloidal system in which: (1) Water is dispersed in fat (2) Fat is dispersed in water (3) Fat and water are dispersed in each other (4) Fat is dissolved
Description : For mass concrete work, the type of cement preferable is [ A ] Ordinary Portland cement [ B ] Rapid hardening cement [ C ] Low heat cement [ D ] Blast furnace slag cement
Last Answer : [ C ] Low heat cement
Description : Saw dust can be rendered chemically inert by boiling it in water containing (A) Ferrous sulphate (B) Potassium chloride (C) Ammonia (D) Nitric acid
Last Answer : Answer: Option A
Description : In designing concrete structures, normally maximum aggregate sizes are adopted with ranges from 10mm to 20mm. Does an increase of maximum aggregate size benefit the structures?
Last Answer : To answer this question, let's consider an example of a cube. The surface area to volume ratio of a cube is 6/b where b is the length of the cube. This implies that ... requirement can offset the disadvantages brought about by discontinuities as suggested by Longman Scientific and Technical (1987).
Description : For ensuring quality of concrete, use (A) Single sized aggregates (B) Two sized aggregate (C) Graded aggregates (D) Coarse aggregates
Last Answer : (C) Graded aggregates
Description : Strength of concrete increases with (A) Increase in water-cement ratio (B) Increase in fineness of cement (C) Decrease in curing time (D) Decrease in size of aggregate
Last Answer : (B) Increase in fineness of cement
Description : In order to obtain the best workability of concrete, the preferred shape of aggregate is (A) Rounded (B) Elongated (C) Angular (D) All of the above
Description : Inert material of a cement concrete mix, is (A) Water (B) Cement (C) Aggregate (D) None of these
Last Answer : Answer: Option C
Description : Workability of concrete is inversely proportional to (A) Time of transit (B) water-cement ratio (C) The air in the mix (D) Size of aggregate
Description : For the construction of cement concrete floor, the maximum permissible size of aggregate, is (A) 4 mm (B) 6 mm (C) 8 mm (D) 10 mm
Last Answer : Answer: Option D
Description : Pick up the correct statement from the following: (A) Continuous grading is not necessary for obtaining a minimum of air voids (B) The omission of a certain size of aggregate is shown by ... in concrete increases the workability but also increases the liability to segregation (D) All the above
Description : C.R.R.I. charts are used to obtain a relationship between strength of concrete and (A) Water cement ratio (B) Workability (C) Grading of aggregate (D) Fineness modulus
Description : The type of aggregates not suitable for high strength concrete and for pavements subjected to tension, is (A) Rounded aggregate (B) Irregular aggregate (C) Angular aggregate (D) Flaky aggregat
Description : The aggregate impact value of the aggregate used in (A) Building concrete is less than 45 (B) Road pavement concrete is less than 30 (C) Runway concrete is less than 30 (D) All the above
Description : Workability of concrete for a given water content is good if the aggregates, are (A) Rounded aggregate (B) Irregular aggregate (C) Angular aggregate (D) Flaky aggregate
Description : If the engineer-in-charge approves, the 10 cm cubes may be used for the work test of concrete provided maximum nominal size of aggregate, does not exceed (A) 10 cm (B) 15 cm (C) 20 cm (D) 25 cm
Description : Pick up the correct statement from the following: (A) A highly absorptive aggregate reduces the workability of concrete considerably (B) The specific gravity of aggregate is important for the determination ... and porosity of an aggregate influence the property of the concrete (D) All the above
Description : Workability of concrete is directly proportional to (A) Aggregate cement ratio (B) Time of transit (C) Grading of the aggregate (D) All of above
Description : Strength of cement concrete primarily depends upon (A) Quality of water (B) Quantity of aggregate (C) Quantity of cement (D) Water-cement
Description : The ratio of differenct ingredients (cement, sand and aggregate) in concrete mix of grade M20 is. (a) 1:1:2 (b) 1:1.5:2 (c) 1:2:4 (d) 1:3:6
Last Answer : (b) 1:1.5:2
Description : For the improvement of work ability of concrete , the shape of aggregate recommended is (a) Irregular (b) Angular (c) Round (d) Flaky
Last Answer : (c) Round
Description : According to the rule of water cement ratio, the strength of concrete wholly depends upon. (a) The quality of cement. (b) The quality of cement mixed with aggregate. (c) The amount of water used in preparation of concrete mix. (d) All of the above
Last Answer : (c) The amount of water used in preparation of concrete mix.
Description : The deleterious materials present in the aggregate (a) Prevent normal hydration of cement (b) Reduce the strength and durability of concrete. (c) Modify the setting action and cause efloresecence. (d) All of the above
Last Answer : (d) All of the above
Description : Which of the following statement is correct (a) The maximum size of coarse aggregate should not exceed one fourth of the minimum dimension of the plain concrete member. (b) The maximum size of coarse ... aggregates of 40mm, 20mm and 10mm sizes are commonly used for concrete works (d) All the above
Last Answer : (d) All the above
Description : For reinforced concrete, the aggregate used is (a) Sand (b) Gravel (c) Crushed rock (d) All of these
Last Answer : (d) All of these
Description : Accordingly to IS: 383-1970, a good aggregate for concrete construction should be (a) Chemically inert (b) Sufficiently strong (c)Sufficiently hard and durable (d) All the above
Description : The material used as an ingredient of concrete is usually (a) Cement (b) Aggregate (c) Water (d) All the above
Description : The workability of concrete is mostly influenced by its [ A ] Water cement ratio [ B ] Aggregate cement ratio [ C ] Cement content [ D ] Water content
Last Answer : [ A ] Water cement ratio
Description : Inert material of a cement concrete mix, is [ A ] Water [ B ] Aggregate [ C ] Cement [ D ] None of these
Last Answer : [ B ] Aggregate
Description : Modulus of elasticity of concrete is primarily influenced by [ A ] Elastic properties of aggregate [ B ] Curing of concrete [ C ] Age of concrete [ D ] Mix proportion and type of cement
Last Answer : [ A ] Elastic properties of aggregate
Description : Which of the following is unsuitable fuel for producer gas manufacture? (A) Coke (B) Anthracite (C) Coal having low fusion point of its ash (D) Coal having high fusion point of its ash
Last Answer : (C) Coal having low fusion point of its ash
Description : Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O)? (A) Blast furnace coke (B) Low temperature coke (C) Anthracite coal (D) Sub-bituminous coa
Last Answer : (B) Low temperature coke
Description : Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature ... release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)
Description : Blast furnace coke is made from coal by (A) Low temperature carbonisation (B) High temperature carbonisation (C) Medium temperature carbonisation (D) Heating the coal in an oven in presence of air
Last Answer : (B) High temperature carbonisation
Description : Pick up the correct statement from the following: (A) Air bubbles in casting produce a dull sound by tapping their surfaces lightly with a hammer (B) Cupola furnace is used for the manufacture of cast iron (C) Red short iron is of no value for welding purpose (D) All the above
Description : During combustion of coal on grate, clinker formation is increased by the (A) Use of thick fire bed (B) Low fusion point of ash (< 1100° C) (C) Use of preheated primary air (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)