Table of Contents
BEST IELTS General Reading Test 234
IELTS GENERAL READING TEST 234 PASSAGE – 2
IELTS GENERAL READING TEST
READING PASSAGE – 2
Thermostat
A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system’s temperature is maintained near desired set point.
Thermostats are used in any device or system that heats or cools to a set point temperature, examples include building heating, central heating, air conditioners, HVAC systems, water heaters, as well as kitchen equipment including ovens and refrigerators and medical and scientific incubators. In scientific literature, these devices are often broadly classified as thermostatically controlled loads (TCLs). Thermostatically controlled loads comprise roughly 50% of the overall electricity demand in the United States.
IELTS General Reading Test
A thermostat operates as a “closed loop” control device, as it seeks to reduce the error between the desired and measured temperatures. Sometimes a thermostat combines both the sensing and control action elements of a controlled system, such as in a motorised thermostat. Thermostats use different types of sensors to measure the temperature. In one form, the mechanical thermostat, a bimetallic strip in the form of a coil directly operates electrical contacts that control the heating or cooling source. Electronic thermostats, instead, use a thermistor or other semiconductor sensor that requires amplification and processing to control the heating or cooling equipment.
A thermostat is an example of a “bang-bang controller” as the heating or cooling equipment output is not proportional to the difference between actual temperature and the temperature setpoint. Instead, the heating or cooling equipment runs at full capacity until the set temperature is reached, then shuts off. Increasing the difference between the thermostat setting and the desired temperature therefore does not change the time to achieve the desired temperature. The rate at which the target system temperature can change is determined both by the capacity of the heating or cooling equipment to respectively add or remove heat to or from a target system and the capacity of the target system to store heat.
IELTS General Reading Test
To prevent excessively rapid cycling of the equipment when the temperature is near the set point, a thermostat can include some hysteresis. Instead of changing from “on” to “off” and vice versa instantly at the set temperature, a thermostat with hysteresis ill not switch until the temperature has changed a little past the set temperature point. For example, a refrigerator set to 2°C might not start the cooling compressor until its food compartment’s temperature reaches 3°C, and will keep it running until the temperature has been lowered to 1 “C.
This reduces the risk of equipment wear and tear from repeated switching, although it introduces a target system temperature Oscillation of a certain magnitude. To improve the comfort of the occupants of heated or air- Conditioned spaces, bimetal sensor thermostats can include an “anticipator” system to slightly warm the temperature sensor while the heating equipment is operating, or to slightly warm the sensor when the cooling system is not operating. when correctly adjusted this reduces any excessive hysteresis in the system and reduces the magnitude of temperature variations. Electronic thermostats have an electronic equivalent.
IELTS General Reading Test
QUESTION 14 – 20
Do the following statements agree with the information given in the Reading Passage?
YES – If the statement agrees with the claims of the writer.
NO – If the statement contradicts the claims of the writer.
NOT GIVEN – If it is impossible to say what the writer thinks about this.
14. A thermostat works well in gadgets that are used for refrigeration than the devices used for heating.
15. A thermostat is used to keep the device’s temperature sustained and close to an anticipated mark.
16. Thermostats are manually operated.
IELTS General Reading Test
17. A heating or cooling apparatus is ceased by a thermostat when they get to a determined temperature.
18. The rate in change of temperature in a target system depends on the quality and storage capacity of thermostat.
19. Until the temperature has adjusted slightly lower than the determined temperature point, a thermostat with hysteresis will not switch.
20. An equipment will wear out more rapidly if the switching rate of thermostat is too frequent
IELTS General Reading Test
READ THE TEXT BELOW AND ANSWERS QUESTIONS 21-26.
Plaster
Plaster is a building material used for the protective or decorative coating of walls and ceilings and for molding and casting decorative elements. In English, “plaster” usually means a material used for the interiors of buildings. Another imprecise term used for the material is stucco, which is also often used for plasterwork that is worked in some way to produce relief decoration, rather than flat surfaces. The most common types of plaster mainly contain either gypsum, lime, or cement, but all work in a similar way. The plaster is manufactured as a dry powder and is mixed with water to form a stiff but workable paste immediately before it is applied to the surface.
The reaction with water liberates heat through crystallization and the hydrated plaster then hardens. Plaster can be relatively easily worked with metal tools or even sandpaper, and can be moulded, either on site or to make pre-formed sections in advance, which are put in place with adhesive. Plaster is not a strong material; it is suitable for finishing, rather than load bearing, and when thickly applied for decoration may require a hidden supporting framework, usually in metal.
IELTS General Reading Test
Forms of plaster have several other uses. In medicine plaster orthopaedic casts are still often used for supporting set broken bones. In dentistry plaster is used to make dental impressions. Various types of models and moulds are made with plaster. In art, lime plaster is the traditional matrix for fresco painting; the pigments are applied to a thin wet top layer of plaster and fuse with it so that the painting is actually in coloured plaster.
In the ancient world, as well as the sort of ornamental designs in plaster relief that are still used, plaster was also widely used to create large figurative reliefs for walls, though few of these have survived. Clay plaster has been used since antiquity. Settlers in the American colonies used clay plaster on the interiors of their houses: “Interior plastering in the form of clay antedated even the building of houses of frame and must have been visible in the inside of wattle filling in those earliest frame houses in which wainscot had not been indulged. Clay continued in the use long after the adoption of laths and brick filling for the frame.”
IELTS General Reading Test
Where lime was not available or easily accessible it was rationed or substituted with other binders. In Martin E. Weaver’s seminal work, he says, “Mud plaster consists of clay or Earth which is mixed with water to give a “plastic” or workable consistency. If the clay mixture is too plastic it will shrink, crack, and distort on drying. It will also probably drop off the wall. Sand and fine gravels were put in to reduce the concentrations of fine clay particles which were the cause of the excessive shrinkage.”
Straw or grass was added sometimes with the addition of manure. In the Earliest European settlers’ plasterwork, a mud plaster was used or more usually a mud-lime mixture. McKee writes, of a circa 1675 Massachusetts contract that specified the plasterer, “Is to lath and seal the four rooms of the house betwixt the joists overhead with a coat of lime and hair upon the clay; also, to fill the gable ends of the house with ricks and plaster them with clay.
IELTS General Reading Test
Questions 21 – 26
Complete the fill ups below.
Write no more than THREE WORDS and/or numbers for each answer.
21. …………….. is an ambiguous phrase to describe plaster.
22. Plaster is interspersed with ………… before use.
23. The fabricated portions of plaster are fixed with ………………… .
24. When dense plaster mixture is used for ornamentation, it may well necessitate a concealed ……….. .
25. Lime was swapped with ………. when it was not effortlessly obtainable.
26. To lessen the disproportionate contraction of clay , …………. And …………. were added to the mixture.
IELTS General Reading Test
ANSWERS ARE BELOW
IELTS General Reading Test
ANSWERS
14. NOT GIVEN
15. YES
16. NO
17. YES
18. NO
19. NO
20. YES
21. STUCCO
22. WATER
23. ADHESIVE
24. SUPPORTING FRAMEWORK
25. OTHER BINDERS
26. SAND AND FINE GRAVELS
IELTS General Reading Test