Natural Resources Essay Example for Free

Natural Resources Essay Renewable energy is energy that is derived from natural resources which can be replenished naturally such as tides, sunlight, geothermal heat, rain and wind. Renewable energy accounts for about 10. 1 of the locally produced electricity in the United States. According to Nebel and Wright, hydro power which is generated using water is the prime source of renewable energy apart from solar energy, wind power, geothermal power and biomass and bio-fuel energies (214). The Tazimina project in Alaska is an example of hydropower plant that does not require a dam. Other hydroelectricity dams are found in Tennessee valley and on the Colorado River. Wind power which uses wind to generate electricity is becoming more and more popular and is mostly used in some regions such as in Appalachians, Western United States and Alaska. Though this source of energy does not pollute the environment it poses negative environmental impacts to wildlife. Although solar technologies and geothermal power have minimal destructive environmental impacts biomass power has the prospective of becoming the leading energy source not only in the U. S but the entire world. Biomass can be produced almost everywhere and is derived from wastes and alcohol fuels and can be converted into liquefied fuel to meet transportation energy requirements. It can also be used to produce electricity and as a source of heat. Ethanol and biodiesel are common forms of bio-fuels used in the U. S and are produced from plants. The U. S department should focus on reconnoitring ways of converting cellulose from forest residue, agricultural wastes and other materials to ethanol which is the most environmental friendly source of fuel. Since the U. S government released $30 million shillings towards the funding of Clean Energies Technologies to enhance the transition to a viable energy future, this can greatly assist in building an inclusive state renewable energy scheme that addresses the full range of market issues and technologies. As it is observed by the World Watch Institute (2006), we all need energy that is secure, improves public health, protects the environment, is reliable, offers technological leadership and addresses climate change. Works Cited Nebel, Bernard J. , and Wright, Richard T. Environmental Science: The Way the World Works. Ed. Upper Saddle, NJ: Prentice Hall, 1987. World Watch Institute, â€Å"American Energy: The Renewable Path to Energy Security†. September 2006. Retrieved on 20th July, 2010 from: http://www. worldwatch. org/files/pdf/AmericanEnergy. pdf

The Lilith in Dracula, Carmilla, Christabel, Geraldine and The Hunger

The Lilith in Dracula, Carmilla, Christabel, Geraldine and The Hunger For centuries Lilith, the Queen of the Night, has been blamed when a child or man dies without certain cause or when a woman refuses to be submissive to her husband.   While the Legend of Lilith is not widely known today, it is not difficult to find information about the demoness. However, there are slight variations found from story to story.   Here we will focus on the myth as found in Hebrew mythology, and we will particularly emphasize the similarities seen between Lilith and various vampires seen in literature today.   The Hebrew figure of Lilith was actually borrowed from Babylonian and Syrian myths.   Lilitu was a Babylonian demon and a spirit of the night and of storms.   Lamassu was a Sumerian goddess and the daughter of Anu, the god of Heaven.   It is believed that Lilith is a combination of these two demons from earlier legends.   However, for the purpose of our study, we will focus on the legend of Lilith found in Hebrew scriptures.   According to Hebrew scriptures, Lilith was Eve’s predecessor and therefore, the first wife of Adam. However, there are two variations on the Hebrew creation myth.   The first states that God made man and woman out of the same material (earth or clay), at the same time, thus the two beings were equals in every way.   The alternative version of this myth states that Adam was made of clay while Lilith was made of dirt and filth.   However, regardless of her origin, the remainder of the myth proceeds much the same way.   Legends states when it was time for the two to have sexual intercourse, Adam insisted that Lilith take the more submissive position.   This angered her and in ... ...le from the Garden of Eden, she was doomed to forever prey on newborn children and suck the blood and life fluids from men.   For this reason, she is the earliest known force of evil, thus making her the perfect image of the mother of all vampires.         Works Cited       Begg, Ean.   The Cult of the Black Virgin.   Arkana: Penguin Books, 1996 pp.34-40.    Bunson, Matthew.   The Vampire Encyclopedia.   New York:   Crown Trade Paperbacks, 1993.    Coulter, Charles Russell, and Patricia Turner.   The Encyclopedia of Ancient   Deities.   London:   McFarland and Company, Inc., 2000, pp. 285-86.    Masters, Anthony.   The Natural History of the Vampire.   London:   Rupert   Hart-Davis, 1972, pp. 170-71.    THE GNOSIS ARCHIVE: Gnostic Studies on the Web.   Accessed on May 1,   2003. http://www.webcom.com/~gnosis/lilith.html   

Friction Lab Essay

Discussion and Review Whenever a body slides along another body a resisting force is called into play that is known as friction. This is a very important force and serves many useful purposes. A person could not walk without friction, nor could a car propel itself along a highway without the friction between the tires and the road surface. On the other hand, friction is very wasteful. It reduces the efficiency of machines because work must be done to overcome it and this energy is wasted as heat. The purpose of this experiment is to study the laws of friction and to determine the coefficient of friction between two surfaces. THEORY Friction is the resisting force encountered when one surface slides over another. This force acts along the tangent to the surfaces in contact. The force necessary to overcome friction depends on the nature of the materials in contact, on their roughness or smoothness, and on the normal force but not on the area of contact or on the speed of the motion. We find experimentally that the force of friction is directly proportional to the â€Å"normal force.† When an object is sitting on a horizontal surface the normal force is just the weight of the object. However, if the object is on an incline then it is not equal to the weight but is calculated by N= mg cos ÃŽ ¸. The constant of proportionality is called the coefficient of friction,  µ. When the contacting surfaces are actually sliding one over the other the force of friction is given by Equation 1: Ffr =  µk FN where Ffr is the force of friction and is directed parallel to the surfaces and opposite to the direction of motion. FN is the normal force and  µk is the coefficient of kinetic friction. The subscript k stands for kinetic, meaning that  µk is the coefficient that applies when the surfaces are moving  one with respect to the other.  µk is therefore more precisely called the coefficient of kinetic or sliding friction. Note carefully that Ffris always directed opposite to the direction of motion. This means that if you reverse the direction of sliding, the frictional force reverses too. In short, friction is always against you. Friction is called a â€Å"non-conservative† force because energy must be used to overcome it no matter which way you go. This is in contrast to what is called a â€Å"conservative† force such as gravity, which is against you on the way up but with you on the way down. Thus, the energy expended in lifting an object may be regained when the object descends. Yet, the energy used to overcome friction is dissipated, which means it is lost or made unavailable as heat. As you will see in your later study of  physics the distinction between conservative and non-conservative forces is a very important one that is fundamental to our concepts of heat and energy.  A method of checking the proportionality of Ffr, and FNand of determining the proportionality constant  µk is to have one of the surfaces in the form of a plane placed horizontally with a pulley fastened at one end. The other surface is the bottom face of a block that rests on the plane and to which is attached a weighted cord that passes over the pulley. The weights are varied until the block moves at constant speed after having been started with a slight push. Since there is no acceleration, the net force on the block is zero, which means that the frictional force is equal to the tension in the cord. This tension, in turn, is equal to the total weight attached to the cord’s end. The normal force between the two surfaces is equal to the weight of the block and can be increased by placing weights on top of the block. Thus, corresponding values of Ffr,and FN can be found, and plotting them will show whether Ffrand FN are indeed proportional. The slope of this graph gives  µk. When a body lies at rest on a surface and an attempt is made to push it, the pushing force is opposed by a frictional force. As long as the pushing force is not strong enough to start the body moving, the body remains in equilibrium. This means that the frictional force automatically adjusts itself to be equal to the pushing force and thus to just be enough to balance it. However, there is a threshold value of the pushing force beyond which larger values will cause the body to break away and slide. We  conclude that in the static case where a body is at rest the frictional force automatically adjusts itself to keep the body at rest up to a certain maximum. But if static equilibrium demands a frictional force larger than this maximum, static equilibrium conditions will cease to exist because this force is not available and the body will start to move. This situation may be expressed in equation form as: Equation 2: Ffr ≠¤  µsFN or Ffr max =  µsFN Where Ffris the frictional force in the static case, Ffr max is the maximum value this force can assume and  µsis the coefficient of static friction. We find that  µsis slightly larger than  µk. This means that a somewhat larger force is needed to break a body away and start it sliding than is needed to keep it sliding at constant speed once it is in motion. This is why a slight push is necessary to get the block started for the measurement of  µk. One way of investigating the case of static friction is to observe the so-called â€Å"limiting angle of repose.† This is defined as the maximum angle to which an inclined plane may be tipped before a block placed on the plane just starts to slide. The arrangement is illustrated in Figure 1 above. The block has weight W whose component WcosÃŽ ¸ (where ÃŽ ¸ is the plane angle) is perpendicular to the plane and is thus equal to the normal force, FN. The component Wsin ÃŽ ¸is parallel to the plane and constitutes the force urging the block to slide down the plane. It is opposed by the frictional force Ffr, As long as the block remains at rest, Ffr must be equal to W sin ÃŽ ¸. If the plane is tipped up until at some value ÃŽ ¸max the block just starts to slide, we have: Equation 3: But: Hence: Or: Thus, if the plane is gradually tipped up until the block just breaks away and the plane angle is then measured, the coefficient of static friction is equal to the tangent of this angle, which is called the limiting angle of repose. It is interesting to note that W cancelled out in the derivation of Equation 3 so that the weight of the block doesn’t matter. PROCEDURE This experiment requires you to record measurements in Newtons. Remember that in SI units the unit of force is called the Newton (N). One Newton is the force required to impart an acceleration of 1m/s2 to a mass of 1 kg. Thus 1 N = 1 kg.m/s2. You can convert any kg-mass to Newtons by multiplying the kg-weight by 9.8 m/s2, i.e., 100 g = 0.1 kg = 0.1 x 9.8 = .98 N. 1. Determining force of kinetic or sliding friction and static friction a. The wooden blocks provided in the LabPaq are too light to give good readings so you need to put some weight on  them, such as a full soft drink can. Weigh the plain wood block and the object used on top of the block. Record the combined weight in grams and Newtons. b. Place the ramp board you provided horizontally on a table. If necessary tape it down at the ends with masking tape to keep if from sliding. c. Begin the experiment by setting the block and its weight on the board with its largest surface in contact with the surface of the board. Connect the block’s hook to the 500-g spring scale. d. Using the spring scale, slowly pull the block lengthwise along the horizontal board. When the block is moving with constant speed, note the force indicated on the scale and record. This is the approximate kinetic or sliding frictional force. Repeat two more times. e. While carefully watching the spring scale, start the block from rest. When the block just starts to move, note the force indicated on the scale and record. You should notice that this requires more force. This force is  approximately equal to the static frictional force. Repeat two more times. Determining coefficient of static friction using an inclined surface a. Place the plain block with its largest surface in contact on the board while the board is lying flat. b. Slowly raise one end of the board until the block just breaks away and starts to slide down. Be very careful to move the plane slowly and smoothly so as to get a precise value of the angle with the horizontal at which the block just breaks away. This is the limiting angle of repose ÃŽ ¸ max. Measure it with a protractor (see photo that follows for an alternate way of measuring the angle) and record the result. You may also want to measure the base and the height of the triangle formed by the board, the support, and the floor or table. The height divided by the length of the base equals the coefficient of static friction. Remember: c. Perform two more trials. These trials should be independent. This means that in each case the plane should be returned to the horizontal, the block placed on it, and the plane carefully moved up until the limiting angle of repose is reached. DATA TABLE 6 Height Base Length ÃŽ ¸ max  µs Trial 1 Trial 2 Trial 3 Average Calculations 1. Using the mass of the block and the average force of kinetic friction from Data Table 1, calculate the coefficient of kinetic friction from Equation 1: 2. Using the mass of the block and the average force of kinetic friction from Data Table 2, calculate the coefficient of kinetic friction for the wood block sliding on its side. Record your result and see how it compares with the value of  µkobtained from Data Table 1. 3. From the data in Data Table 3, 4 & 5 compute the coefficient of static friction,  µsfor, the glass surface on wood, the sandpapered surface on wood, and wood on carpet, etc from each of your three trials. Calculate an average value of  µs.Record your results in your own data sheets. 4.  From the data obtained in Data Table 6 calculate  µsfor wood on wood from each of your three trials. 5.  Calculate an average value of  µs. Record your result on the data sheet. Questions A. How does the coefficient of static friction compare with the coefficient of kinetic friction for the same surfaces and areas? B. Why is it important to reduce friction during the operation of machinery? C. How does grease or oil affect the coefficient of friction?

Artists and Their Muses in Wildes The Picture of Dorian...

Both Oscar Wilde and Virginia Woolf’s novels depict the image of an artist and their muse. Within The Picture of Dorian Gray, Basil Hallward is inspired by Dorian Gray to create his greatest work of art. While in To the Lighthouse, Lily Briscoe finds her inspiration through Mrs. Ramsay and through her art she is able to blossom into her own woman. Briscoe grows through her art while Hallward is killed because of his masterpiece. The fates of the two artists differ so vastly because of how each artist envisions the idea of legacy and how they connect to their own muse. To the Lighthouse and The Picture of Dorian Gray both present the dichotomy of legacy into male and female legacy. The women within Virginia Woolf’s novel come to see†¦show more content†¦Mr. Ramsay’s ideation is also present within Oscar Wilde’s novel The Picture of Dorian Gray. The idea of legacy is clearly shown when Dorian Gray has a moment of pure envy and states, â€Å"I am j ealous of everything whose beauty does not die† (Wilde 29). While Mr. Ramsay desired the stagnation of his philosophical ideas and literature Dorian desires the stagnation his own of beauty. Throughout the novel both Dorian and Henry Wotton describe beauty as an ever fleeting thing that is the most vital to life. Dorian is willing to sell his soul to the devil in order to maintain his legacy of beauty. Dorian attempts to live hiding his horrid painting deep within his home, but soon the moral ugliness of the painting catches up with him and he meets his demise. Both Mr. Ramsay and Dorian Gray fail at their goals and this depicts how the male version of legacy can only end in failure. Nothing lasts forever and as Mr. Ramsay states, even the pinnacle of literature, Shakespeare will fade into nonexistence. Thus the male form of legacy pushes forward the idea of immortality while also depicting immortality as an unfeasibility. Through this mindset men are expected to desire this i dea of legacy, but at the same time they are expected to fail. This ideation reinforces the Ruskinian ideal and gives women the responsibility to console the men in their lives. Within The Portrait of Dorian Gray Basil does not have a woman within his life instead he