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FRACTURE TOUGHNESS OF A TEMPERED GLASS BASKETBALL BLACK BOARD
MUNA ARIF
UID : U93198700
Graduate Student, Department Of Mechanical Engineering
1. INTRODUCTION OF TEMPERED GLASS :
• When a normal glass undergo a process of extreme heating and cooling it become harder which is called as tempered glass.
• The brittle nature or property of tempered glass will make it to break into small oval shaped pieces, thus eliminating the danger of injuries.
• Tempered glass fail long after the impact of extreme load, this is because of continuous stress acting within the layer of glass that was been generated during the tempering process. Thus we can say that tempered glass break or fail long after when compare to that of normal glass.
2. Manufacturing Process of Tempered glass
A normal glass undergo a process of following stages :
1. A normal glass is first pass into a hot furnace where it is been heated up to temperature of 650 degree Celsius. At this stage the glass become in molten form and increases the elasticity of it .
2. After the heating process the glass is been passed through air quenched where it under go rapid cooling. During this process the glass undergo with many different type of stress.
3. All the cutting and drilling process is been done before the temper the glass.
3. Reason for using tampered glass in basketball board:
Thermal Resistance :
When a tempered glass is been used in basketball board it will face continuous heating from sunlight in unevenly panes, causing stress that might lead to cracking, but since during the therm...
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...sketball board fail at the edges and propagates through to the other surface of glass thus making crack propagation and failure. In order to avoid this frame should be installed at the center since we have more stress capacity at the center surface area than on the edges.
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6. General consideration for improvement of fracture toughness of tempered glass of basketball board.
• Cutting and drilling:
We have to insure that all the cutting and drilling process should be carried out during tempering process, since during the extreme heating stage the glass in a molten form will have more elasticity due to which the damage or crack may not occur.
• Surface Disorder:
The surface disorder will occur during the tempered process stage of extreme heating and rapid cooling; this uneven surface will decreases the strength of glass because of different stress impacts.
Glass transition is not the same as melting. Melting (or freezing, or boiling or condensation) undergoes a change in heat capacity and a latent heat is involved or in another term, melting is a first order transition that only occurs in crystalline polymers. However, for glass transition, it is a second-order transition that only occurs in the amorphous polymers and does not involve latent heat since amorphous polymers have a relatively weak intermolecular forces that bond them together and can be broken once heat is applied whereas crystalline polymers have a strong primary (cross-linking) covalent bonds. Glass transition temperature and melting temperature can occur in the same process because in a semi-crystalline polymers, both amorphous and crystalline regions exist where the amorphous polymers undergo only the glass transition and the crystalline polymers undergo only
projected its rays through the tinted glass... But in the western or black chamber the effect of the
* Heat the end of the glass tube so as to close it. The tubeÂ’s end
To understand the state of glass we must first have an understanding of the different states of matter. All matter is composed into states, and may move through these four existing states. The solid state is where the atoms of a substance are closely pact together with the only movement being the vibration of the atoms. The liquid state is where atoms are placed together in no order with a definite volume, but may move past each other giving it no definite shape. According to Science Magazine’s article in 1926 , glass exhibits traits from both of these states. It is similar to a liquid in that its atoms are randomly arranged, yet it has the fixed rigid bonding of a solid as well as the same high heat capacity(Science). This article in Science Magazine is a bit dated though and science changes drastically through years, especial...
A hot plate is acquired and plugged in and if left to warm up. Fill two beakers with 0.075kg of water and record the temperature using a thermometer and record it. Place one of the beakers onto the hot plate and drop one of the metal objects in. Wait for the water to boil and wait two minutes. Take the object out of the water and drop it into the other beaker. Take the temperature of the beaker and record the rise in temperature.
By exposing the chocolate and the cookies before the light and heat of the 60-watt light bulb, the students will be able to progressively observe the process of the material melting and make records at every stage of the experiment. Using the 15 seconds step, the students can identify the melt temperature and time of the chocolate under the lab conditions as well as make and analyze their records in the final part of the experiment. The experiment is expected to establish, which of the chocolates and cookies melt faster, and make conclusions about the influence of the consumables ingredients on their physical properties. This corresponds with the TEK 112.11 (5B) procedure, which allows students to “observe, record, and discuss how materials can be changed by heating or
The explicit presentation of the mathematics involved in the Arrhenius equation (Michels, Tsong, and Smith 1983) rendered the parameters involved in glass hydration understandable. However, the actual implementation of the physical processes described in the mathematical equations into a model replicating the natural environment is a complicated problem hard to solve (Stevenson 1998).
The primary goal of this experiment was to determine which types of glassware are the most accurate and precise in measuring substances. Another goal of this experiment was to help familiarize ourselves with the different types of glassware, and how we should handle the laboratory equipment. The accuracy and precision of a particular type of glassware is important because it allows for accurate measurements when performing different experiments. It also allows us to differentiate between glassware that is better for containing substances versus glassware that can deliver substances more accurately. In order to measure the accuracy and precision of the different types of glassware, we first chose seven different types of glassware. The general
Today safety glass, which will not splinter when exposed to shock, is in windshields for cars. Essential as it is, safety glass was the result of a clumsy mistake. In 1903, Edouard Benedictus, a French scientist inadvertently knocked a glass flask to the floor when fetching reagents. He heard the glass shatter, but later, he saw the broken pieces of the flask still hung together, more or less in their original contour. Then he learned that the flask had recently held a solution of cellulose nitrate, a liquid plastic, which had evaporated, apparently depositing a thin coating of plastic on the flask’s interior. He experimented with coating glass with liquid plastic, then shattering it and it was not broken. When Benedictus read that most of the drivers seriously injured had been cut by shattered glass windshields, he knew that his unique glass could save lives. Unfortunately, automakers were uninterested in the costly safety glass for windshields. It was not until the outbreak of World War I that safety glass found its first application: as the lenses for gas masks. After automobile executives examined the proven performance of the new glass under the extreme conditions of battle, safety glass’s major application became car windshields. It was very dangerous when something hit your car, the glass was broken and as a result, you would be sore and even dead. But with this unbreakable glass, now you don’t have to worry about this because nothing can touch you from the outside.
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The air in between the layers of glass should be thick and dense, so that it can save energy. One of the most common airs used in-between glass is argon. When argon is used heat loss is reduced. You could also use carbon dioxide or sulfur hexa-fluoride between glass.
When a blunt object collides with the eye ball, it first pushes and deforms the eye ball inward, also creating stresses within the tissue. As the blunt object continues to push on the eye ball the pressure within the eye increases, which causes the stresses within the tissue to further increase. When these stresses are high enough, the tissue begins tearing at the weakest point in the wall of the eye, and continues until the tear goes completely through the wall.
During impact most of the impact energy in the test specimen is absorbed as plastic deformation when the test specimen yields. Temperature and strain rate effect the yield behaviour and ductility of the material and hence affect the impact energy. Materials that behave this way usually have body-centred cube crystal structures and where lowering the temperature reduces the materials ductility.
In order to learn how glass fractures, we must first learn the composition of glass and the different types of glass. Glass is a hard, brittle, amorphous substance composed of sand (silicon oxides) mixed with various metal oxides. When sand is mixed with other metal oxides, melted at high temperatures, and then cooled to a rigid condition without crystallization, the product is glass (Saferstein, 2010). Glass can come in many different forms all of which can range from very brittle glass to bullet proof glass; the stronger the glass, the more ingredients are required and the more complex the process is.
Lynn Yarris “New Glass Tops Steel in Strength and Toughness” newscenter. January 10, 2011. web.5 december 2013.