...(i) Injection Molding Demonstration Battenfeld HM 40/130 is the machine used in the laboratory session to mold Polypropylene. Thermoplastic materials such as nylon, polystyrene, polythene and polypropylene can be used in a process called injection molding. How injection molding works? 1. The hopper is filled with granules of plastic powder. The hopper stores the material until it is needed. 2. The heater starts heating up the tube until it reaches a high temperature, then a screw thread starts turning. 3. The granules are pushed along the heater section by a motor, which pushes the granules along the heater section. The heater melts the granules until they reach the liquid state. This liquid is then forced under pressure into a mold where it cools down the liquid and solidifies it, which then turns into a shape. 4. The mold then opens and the ejector pins remove the molded part. In one molding cycle, the maximum amount of plastic injection mold that can be injected is called the “shot size”. For best quality, parts must use about 60% to 70% of a machines rated shot size. Larger shot sizes will not allow sufficient melt cushion for packing. Smaller shot sizes produce greater irregularities and loss of precision. The relatively high melting point of polypropylene allows continued use at 104°C. The resin begins to soften at about 121°C. The polymer “Polypropylene” (C3H6)n properties: Property Value Molecular weight of repeat unit 42.08 g/mol...
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...Sulfuric acid was injected into the stratosphere. This also created a reduction in sunlight to the Earth by 20%. Because the atmosphere was filled with this acid and dust clouds the plant life and small creatures would die off. It takes at least 10 years for the atmosphere to clear itself of these pollutants. An impact such as this can also produce acid rain. There are many animals that can not handle acid rain. Therefore, this would also play a part in extinction of species. (www.tulane.edu). When it comes to how scientists determine the composition of ancient atmospheres, I found the following; “Ages of ice samples found on the Earth cover a span approaching 200,000 years. Gas bubbles trapped in that ice can be used to learn about the composition of Earth's atmosphere at the time they were trapped in the ice. But how can we tell what the Earth's atmosphere was like before that? Recently, USGS scientists have used a gas QMS to determine the oxygen level of ancient samples of Earth's atmosphere from a most unlikely place - amber. The...
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...Scientist also obtain the past climate change from the ice core. Ice core has trapped a lot of gas bubbles, including greenhouse gases such as CO2 and methane. Therefore, scientists and researchers can obtain the CO2 concentration from the ice core. The graph below (fig.2) has shown the CO2 concentration at different age in b2K, which is age in years before AD2000. You can see the CO2 concentration is actually fluctuating in a cycle. When the CO2 concentration has reached its upper limit, it dropped again. (fig.2 CO2 concentration from gas bubbles in EPICA Dome D ice core) However, there is a trend that the CO2 concentration is increasing. What about other proxies of Cenozoic? (will be...
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...Some people with extreme allergies are stuck in a bubble, but the entire human race is trapped in a bubble. That bubble is gender, and the role it plays in dividing our society. Octavia E. Butler’s explores this concept in her novel “Dawn”. Butler first demonstrates the walls that gender roles create by switching what humans see as the typical gender roles. The female ooloi are tall, and are not as open and talkative as what is seen as normal. The males have a more approachable nature. The “teachers” are also male. Although Butler flips the roles of male and female, she still introduces the genderless Oankali to show that no matter what traits males and females if humans define themselves as different they cannot create a society that will...
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...It has been noted that many college campuses, that students create their own circles of like-minded individuals without confronting any difference in opinions. Which is an unfortunate situation for colleges when it is supposed to be a safe environment for students to discover diversity within the campus. By continuing to stay in a bubble of their own ideas and beliefs can cloud a student’s views on the world which can lead people to create assumptions about those outside their comfort zone. This exact situation is discussed in an article by Jonathan H. Adler, a professor at the Case Western University School of Law, called, “Against Campus Echo Chambers,” where it highlights how students inhabit liberal bubbles where they are reluctant to encounter...
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...FLOWMETER MEASUREMENT APPARATUS CHE331 CHEMICAL ENGINEERING LABORATAR Date of experiment performed: August 6, 2014 ABSTRACT The Flowmeter Measurement experiment was conducted to obtain the flow rate measurement by utilizing three basic types of flow measuring technique which is rotameter, venturi meter and orifice meter and to investigate the loss coefficient of fluid through 90 degree elbow. The apparatus was placed on bench. The inlet pipe was connected to bench supply while the outlet pipe into volumetric tank. Pump supply was started up when bench valve was fully closed and the discharge valve was fully opened, then bench valve was slowly opened until it is fully opened. The reading on manometers (A-J) was recorded and the flowrate was measured. The steps were repeated for different rotameter. TABLE OF CONTENTS 1.0 Introduction 2.0 Objectives 3.0 Theory 4.0 Diagram and Description of Apparatus 5.0 Experimental Procedures 6.0 Results and Discussion 7.0 Sample calculations 8.0 Conclusions and Recommendations 9.0 References 10.0 Appendices INTRODUCTION In the industries, flow meter is used to measure the volumetric flow rate of fluids by introducing a constriction in the flow. The pressure difference caused by the constriction is correlated to the flow rate using Bernoulli’s theorem. In this experiment, SOLTEQ model FM101 is used to measure the different of pressure across the venture and orifice...
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...Test 2 – AF202 Prep |Basic Anatomy Gas Laws | |Part 61 Certification Pilots, Flight Instructors and Ground Instructors | |.14—Refusal to submit to a drug or alcohol test | |.15—Offenses involving alcohol or drugs | |.16—Refusal to submit to an alcohol test or to furnish test results | |.23—Medical certificates: Requirement and duration | |.31g—Additional training required for operating pressurized aircraft capable of operating at high altitudes | |.53—Prohibition on operations during medical deficiency | |Part 67 Medical Standards & Certification | |Part 91 ...
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...global warming occurs. The first step to global warming is that the suns heat waves pass through the atmosphere. The next step, which is the problem, is that some heat waves are trapped by the atmosphere. The earth absorbs most of the radiation but only some of the energy is sent back into space. But as time goes by we are polluting our earth which then thickens the atmosphere that makes Global warming happen faster and faster. 3. The Earth’s temperature fluctuates but what is its general trend?________ The earth’s general fluctuation trend is varies. It goes up and down. It seems that both up and down parts are rising slightly. The up part rises a little higher than the down part. Some might only notice a difference by mid 1960’s. 4. The Earth’s carbon dioxide levels fluctuate from summer to winter. What causes this natural fluctuation? The reason earth’s temperature fluctuates is because most of the land on our earth cover the northern hemisphere instead of the southern hemisphere. When the northern hemisphere is facing the sun (during summertime), the leaves are able to breathe in CO2. When the northern hemisphere is tilted away from the sun (in the fall/winter), the leaves fall and breathe out CO2. 5. What can bubbles of atmosphere trapped in glacial ice tell us? The bubbles of atmosphere in a glacier give the amount of CO2 that was in the air the year when it was snowing. It can also tell us what the climate was the year when it was snowing very accurately...
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...Introduction: Vostok is a Russian research station in the East Antarctic. Vostok sits on top of a Subglacial Lake underneath one of the thickest Ice Sheets measuring over 4 km. However, what makes this an ideal location for collect ice core samples is because the ice has remained undisturbed for the last interglacial and the penultimate glacial periods. Data: The Vostok dataset contains columns that give the depth (in meters) of the ice core, the "ice" and "gas" ages (in thousands of years ago), concentrations of carbon dioxide and methane found in the ice bubbles, the hydrogen isotopic ratios, and a column that provides information on dust. Analysis: The age of the ice is obtained by counting layers of ice that are deposited year after year that separate the warm and cold periods with the oldest on the bottom and the youngest on the top. The gas age is calculated assuming that the bubbles of gas can only be trapped effectively in layers of older ice, where the pores in the ice close, sealing the air at a depth well below the surface in a process is called sintering. That is why in figure 1. the gas age is below the ice age as a function of depth. Similarly the isotopic composition of water is indicative of the temperatures of the environment. During cold periods, the concentration of the heavy isotope of oxygen, (18O), relative to, (16O), is lower than during warm periods. The reason for this is that at lower temperature, the moisture has been removed from the atmosphere...
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...head free by the snow took over. My body had succumb to the cold heavy trap. Hyperventilating from the stress of being trapped I thought about Zoey. Was she ok? Did she get trapped like me? I tried to scream for help, but my voice wouldn't work. It felt like something in side of me was pulling it out, squeezing and breaking it. I couldn't open my mouth it felt like it was glued shut and all that came out was a quiet, “squeak”. I started digging at the snow by my hands to get up to my face. I knew that I was running out of air. I finally got one arm out and dug harder and harder to make an air bubble for me to breath. The air felt thinner and thinner as I was hyperventilating. My body was frantically moving and wiggling trying to get any body part out of the trap. First my feet started to get numb then my finger and nose. Blowing into my hands trying to warm them up I heard something. “Ruby! Ruby! Where are you! Are you ok!” Zoey screamed from far away. Her voice sounded clear and worried. She must have been fine. I knew she would never hear my squeals from all the way down the mountain. Still I tried, my just kept getting weaker until it was completely gone. “Ruby I hope you are ok. I am going to ski down the mountain and get help” Still worry in her voice as my hopes of being found disappeared. I started to decrease my breaths as to save the oxygen in my air bubble. As time went by I heard no one anywhere around me and my body got colder. As my optimism was slowly fading away then...
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...level to vocalize my thoughts. I always feared what others would say, think or what if I failed etc. It was a never-ending list of 'what-ifs'. It grew to such an extent that I would avoid instances where I had to face people like competitions, student council interviews, elections etc. What I did not realize was that over time, the fear had become a bubble in which I was trapped and could not get out. Teachers and friends had started assuming that I had nothing to say. I realized that the only way to get my place in the society's pyramid was by doing the work assigned to me to the best of my capabilities and having excellent manners. I inculcated both in myself that I became someone whom all teachers and students depended on to get the work done. The turning point of my life came, when I decided that it was time for me to burst the bubble and face my fear of facing people. In Grade 10, I decided to join the student council of the school. It was a long process that included an interview by the coordinator and other teachers. The day they called us for interview, I was terrified. I felt like I was slipping back into the bubble without actually taking a step forward. But an old teacher of mine had told me these words which I will never forget for the many years to come -" The greatest barrier to success is the fear of failure." I entered the room for the interview and as I feared, I...
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... SONOLUMINESCENCE: How Bubbles Turn Sound into Light S. J. Putterman and K. R. Weninger Physics Department, University of California, Los Angeles, California 90095; e-mail: putterman@physics.ucla.edu Annu. Rev. Fluid Mech. 2000.32:445-476. Downloaded from arjournals.annualreviews.org by NORTH CAROLINA STATE UNIVERSITY on 08/14/09. For personal use only. Key Words energy focusing, nonlinear dynamics, complexity, hydrodynamics gas bubble, continuum mechanics, shock shape instabilities, chemical hydrodynamics Abstract Sonoluminescence, the transduction of sound into light, is a phenomenon that pushes fluid mechanics beyond its limit. An initial state with long wavelength and low Mach number, such as is realized for a gas bubble driven by an audible sound field, spontaneously focuses the energy density so as to generate supersonic motion and a different phase of matter, from which are then emitted picosecond flashes of broad-band UV light. Although the most rational picture of sonoluminescence involves the creation of a ‘‘cold’’ dense plasma by an imploding shock wave, neither the imploding shock nor the plasma has been directly observed. Attempts to attack sonoluminescence from the perspective of continuum mechanics have led to interesting issues related to bubble shape oscillations, shock shape instabilities, and shock propagation through nonideal media, and chemical hydrodynamics. The limits of energy focusing that can be achieved from collapsing bubbles in the far-off equilibrium...
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...most brutal of critics: society. Any theater enthusiast understands the exhausting work and effort required to make the production perfect, but to the common audience what is behind the curtains remains hidden. I was not able to see my true beauty because I was so focused on always delivering a larger and more extravagant show to keep my audience returning. Feeling lonely, trapped and unhappy made me not appreciate lief to the extent that i could have done. I lived everyday hoping and praying that the curtains would never drop. Coming to the U.S. helped me incredibly much. Making new friends, being shown love and acceptance everyday made it possible to find the strength to change my ways. People are so much more open minded and they showed me that being who i am is cokay. With all ups comes downs and my dragons breath slowly started to...
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...HEAT 4.1 UNDERSTANDING THERMAL EQUILIBRIUM 1. Define: The measure of the degree of hotness of an object. (a) Temperature Measured in SI unit Kelvin, K A hot object is at a higher temperature than a cold object. Form of energy, measured in Joules, J (b) Heat Heat is transferred from hotter object (higher temperature) to colder object (lower temperature) When an object is heated, it will absorb heat energy and the temperature will increase. When an object is cooled, it will release heat energy and the temperature will decrease. (c) Thermal Two objects are in thermal contact when heat energy contact can be transferred between them. (d)Heat transfer When two objects with different degrees of hotness come into thermal contact, heat energy is transferred between the two objects. (e) Mechanism of Thermal Equilibrium Energy is transferred at a faster rate from the hotter object to the colder object. Energy is also transferred from the colder object to the hotter one, but at a slower rate. There is a net flow of energy from the hotter object to the colder object. (f) Thermal When two objects are in thermal equilibrium, there is Equilibrium no net flow of heat between them. Two objects in thermal equilibrium have the same temperature 60 The hotter object cools down while the colder object warms up . After some time, energy is transferred at the same rate between the two objects. There is no net heat transfer between the objects. The two objects are said to be in thermal equilibrium...
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...bankers and investors accompanied by the soaring housing prices, countless cheap money and easy loans generated along with the creation of the credit default swap; and the crash of major banks, these were the crucial factors that led to the recession in 2008. First, the optimism of bankers and investors triggered the start of the economic crisis as they refused to believe the economy was crumbling because it was doing too ‘good’ to fail. As investors see the positive and profitable chance of gaining money, they were incentivized to purchase shares with the expectations of making money. The surge of this action eventually made the economy stuck in a bubble as investors felt it was an easy opportunity to gain money since it was safe and secure. Mob mentality drove the process of the bubble on action. The bubble itself was the housing bubble. However, consumers and bankers had undermined the problem that the prices were not driven...
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