Topics in Basic TechnologyCeramics: Types of Ceramics Advantages and Disadvantages of Chain drives Len Academy Questions for Basic Technology JSS3, 2nd Term, 2020 Len Academy Question for Basic Technology, JSS3, 2nd Term, 2020, Part 2 Belt and Pulley Drives: Types of Belt in Belt Drives Electromechanical Energy: Parts of the Refrigerator and how they operate Chain Drive, Types, Classifications, Advantages and Disadvantages Advantages and Disadvantages of Belt Drives Type of Lines in Technical Drawings Len Academy questions for Basic Technology, JSS2, 2nd Term Len Academy questions for Basic Technology JSS2, 2nd Term, Part 2 Maintenance, Types of Maintenance Hardwood and Softwood - Characteristics and Examples What are Ceramics? Characteristics of Ceramics
Academic Questions in Basic Technology
Which of the following is not a type of maintenance?
Which of the following is incorrect concerning preventive maintenance?
A. It is considered to be the best form of maintenance
B. Immunization is a form of preventive maintenance
C. Worn out parts may be discovered when preventive maintenance is carried out
D. Preventive maintenance is defined as the repairs carried out on an equipment or object after a correct prediction of an impending fault
E. A person who services his car monthly practices preventive maintenance (even though the car functions properly)
F. The main goal of preventive maintenance is to stop a device from breaking down suddenly
The following statements are true concerning wood except _____.
A. It is an inorganic material
B. It is a structural tissue
C. It is composed mainly of cellulose
D. Hardwood and Softwood are types of wood
E. It constitutes the stems and branches of trees
F. It is porous and fibrous
Which of the following is not a characteristic of hardwood?
A. They are more fire resistant in comparison to softwood
B. Their stem are divided into trunks called dendritic form
C. Birch, Teak and Alder are examples of hardwood
D. They always have a higher density than softwood of the same mass
E. They are suitable for making deckings in buildings
F. Most hardwood are expensive than softwood
The outermost covering of a wood is called the _____.
A. Wood skin
The followings are characteristics of ceramics except _____.
A. They readily undergo oxidation
B. They have high melting point
C. They are durable
D. Most are insulators but graphite is a conductor of electricity
E. Most are non-magnetic
F. They have great tensile strength but graphite is soft
Which of the following statement is false of ceramics?
A. They are not metals
B. They are not plastics
C. Ceramics can be absolutely defined by its products characteristics
D. Ceramic materials are not organic in nature
E. Ceramics are refractory in nature
F. Ceramics materials are usually made from clay
Which of the following is not a function of thin continuous line in Technical drawing?
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The chain drive is one of the mechanisms through which power is transmitted mechanically from an engine to the wheels via an endless rotating chain.
Using a tractor as an instance, you probably had seen some of its large chain wheels. These massive chains are responsible for transmitting power and kinetic energy (energy in motion) via the rotational movements of the chains. The rate of rotation of these chains results in the speed level of the tractor.
Apart from the tractor, some of the other mechanisms of power transmission that utilizes the chain drive technology include:
The image below shows the Roller Chain (which is a type of Chain Drive):
Note: A chain drive consists of an endless chain running over two sprockets.
Think of the sprockets as toothed wheels over which an endless rotational chain is fitted.
The chain; often called; roller chain or drive chain or transmission chain is used to convey power over two sprocket wheels with its edged teeth meshing with the holes at the center of the chain.
Chain drives are employed or utilized in diverse areas; some of which include:
Based on the utilization or uses of the chain drives, they can be classified into three types:
Below are explanations of the various types of chain drive:
The roller chains are very common since they are used in bicycles, motorcycles and vehicle engines.
They are made up of a series of small cylindrical rollers attached together at both sides of its entire length.
The roller chain requires the sprockets in order to transmit mechanical power. (Please see the image of the Roller Chain in the above diagram).
Note: Roller chains can be single-stranded or multiple-stranded.
Also called the inverted tooth chains, the silent chains are series of toothed link plates that are attached to one another in a pin-like manner that allows for free flexing of the chains.
Note: It is difficult to connect together the silent chains from different manufacturers.
Silent chains operate with reduced noise levels and can transform more loads and at a higher speed than a roller chain of the same width.
They are preferably used in industrial equipment where quietness, silence and smoothness are required.
They are preferable used for lifting processes rather than power transmission. They don’t need meshing with sprocket sockets because they are made to run over sheaves.
Leaf chains are commonly utilized in trucks that lift large and heavy loads.
The flat-top chains are manufactured for the purpose of conveying materials; thus are widely used in conveyors.
They consist of plates made up of steel with hinge-like barrels curled on each side with pins inserted into the barrels to create joints acting as both beams and bearings.
The connecting pins in a flat-top chain are usually enlarged or knurled at one end, giving rise to its continuous length.
Detachable chains are made up of similar links that can be easily detached from one another. Each of the link comprise of a hook-shaped end in which adjacent articulation occur.
Detachable Chains will usually transmit power at lower speed.
Detachable chains can be easily assembled and disassembled by pulling up the slack and flexing the links, then sliding a link sideways.
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Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.
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Amazing facts in Basic Technology
Rubber bands last longer when refrigerated
Lighter was invented before matches
Johann Wolfgang Dobereiner was credited with the invention of lighter in 1826 while the actual match was made 3 years later
Volkswagen group of companies own some of the top cars of the world. These are Audi, Bentley, Bugatti, Ducati, Lamborghini and Porsche
NOTABLE POINTS IN Basic Technology
Preventive maintenance is carried out routinely on a device even though no apparent fault may be present on such device.
The goal of preventive maintenance as the name suggest is to prevent a sudden breakdown on a device or equipment.
As an instance, a person who services his or her car monthly even though the car is still able to function correctly is said to be carrying out preventive maintenance on the car.
In the course of a preventive maintenance, worn out parts may be discovered and replaced as soon as possible. Also, there may be a change of oil while other little adjustments may also be carried out.
We can even carry out preventive maintenance on our body to prevent certain diseases. For this reason, some persons have discovered cancerous cells in their body through regular medical checkup; and were able to kill such cells before they become malignant.
As a matter of fact; immunization is a form of preventive maintenance.
Hardwoods are derived from angiosperms. They show the following characteristics:
They usually have a higher density than softwood. Balsa is an exception.
They are usually more expensive than softwood.
They grow at a slower rate than softwood.
Hardwood trees shed their leaves in certain times of the year.
Hardwood are more fire resistant than softwood.
The leaves of hardwood trees are evergreen.
They are used for making quality furniture (in terms of strength). They are also suitable for decking in buildings.
Hardwood trees always have divided trunks which are sometimes referred to as a dendritic form.
In terms of price, hardwood are usually more expensive than softwood.
Examples of hardwood include iroko, ash, beech, alder, teak, birch, mahogany, maple, oak, balsa and walnut.
Ceramics are refractory. They also require a very high amount of heat and subsquent cooling to be formed.
Being refractory means that they are capable of withstanding a variety of abuses like high temperatures and chemical attacks.
Ceramics are generally made by taking clay from the ground and mixing it with water. It is then shaped into any form and fired inside an oven (called kiln) at a very high temperature. They may then be decorated with a waterproof, paint-like substances called glazes.
Ceramics may have constrasting physical and chemical properties (or characteristics); but in general,
They have high melting points.
They are heat resistant.
They can be very hard with great strength; although a few are brittle or soft; for example, graphite.
They are durable (last for a long time).
Most are electrical insulators (cannot conduct electricity) but; graphite is an electrical conductor.
They are chemically unreactive or inert.
They are not easily oxidized.
Most are non-magnetic.