Wednesday, January 29, 2020
Torsional pendulum final experiment Essay Example for Free
Torsional pendulum final experiment Essay To improve reliability of my results I will perform 3 runs for each measurement rather than 1, this will allow me to average the 3 results for each measurement which will improve reliability of results, and if there is one of the 3 that does not fit it can be excluded and average the other 2. I will no longer need to do 5 oscillations and then divide by 5 as the accuracy of the readings by the light gate ensures that the experimental error will already be eliminated as human error and reaction time no longer applies. Â I will scale up parts of the experiment which produced larger than expected error. Therefore I will use a larger diameter of wire, which will therefore reduce the percentage error as the accuracy of the micrometer will still be the same. Â The time period was where the majority of the errors occurred in the preliminary. Therefore I am going to use a light gate to measure the time period, this will reduce error on the time period significantly. It will eliminate the human error as the error due human reaction time will no longer apply. There will only be a reading error now, which is far less significant than the experimental error. I will use a range of lengths from 100-500mm rather than 100-800mm, as when the length becomes very long the bar on the bar on the wire tends to wobble a lot more than when a shorter length is used. Therefore I am hoping this will further reduce the error in the time period. I will go up by 50mm each time so that I get a suitable number of results. Aim: Investigate the effect of changing the length of wire on the time period for a Torsional pendulum. Equipment: Â Retort Stand with clamp to hold the wire and bar when oscillating and to hold the motion sensor. Bung cut into two halves so I can change length of the wire easily and hold the wire tightly. Â Metal Bar which will move through the motion sensor to give time periods. Approximately 0. 700,m long wire( extra 200mm to allow for tying wire and excess at top of clamp to easily be able to change length) Â Laptop with Sensing science (graph) software which logs the data in real time. Â Light gate including easy sensor and cables, this will measure the time period. Micrometer to measure diameter of the wire. Â Meter long ruler to measure out correct lengths of wire and measure length of the bar. Diagram: Fair test. It is important to make the experiment fair to ensure reliability of results. The following must be considered when carrying out my experiment. Â Ensure the same bar is used for each run so that these constants (mass and length) dont change. Ensure the diameter of the wire is the same for the whole length, take readings at regular intervals on the wire to be sure. Turn 90 degrees anticlockwise for each time period measured, as the twist on the wire will be different otherwise. Also ensure that before turning 90 degrees that the wire and bar are in the equilibrium position, 0 angular displacement / no twist. Theory: As I predicted in the preliminary I expect the time period to increase as the length of wire increases, this is due to the equation derived in my research above. T=2? Where theoretically the relationship between time period and length should be T? L0. 5. However, from the equation I can see that the diameter is to the power of 4, therefore even a very small change in diameter will cause a major difference in the time period, therefore using a greater diameter will cause the denominator to be much larger and so the overall time period will be significantly lower. For example I will expect the time period for 0. 1m to be significantly less than 6. 162s, which is obtained from the preliminary using a smaller diameter. Using the theory above I can make a predicted graph of what I am expecting from my log log graph, by simply putting the lengths into the formula, as I already have the measured diameter of wire, length and mass of bar. This is what I obtained. This shows that I should obtain exactly 0. 5 as the gradient and the R squared correlation should be as close to 1 as possible to represent a strong correlation Method: Â Set up the apparatus shown above, connect lead into laptop and open sensing science software, select com1. Set the time to 30 seconds and tick light gate sensor.* Measure the length of the bar using a meter ruler and the mass using a scale. Â Get two 700mm copper wires and tie them together ensuring that the diameter is constant for the whole length. Then connect the wire to the metal bar, attach the wire to the bung and tighten. Measure the diameter of the wire at a few intervals and ensure that it is the same, record this diameter. Rotate the bar 90 degrees anticlockwise and let go, and at the same time press on run on the laptop. Allow the bar to complete 3 oscillations; this would be 2 peaks, 3 times, as shown below. Once 3 oscillations are complete then click the stop button. Click on interval and hold and drag from one peak to 2 peaks later, this will give you the time period for one oscillation. Record this in a suitable format and do the same for the next 2 oscillations. Â Repeat this process for lengths 100-500mm going up by 50mm each time, this will ensure I have enough results to be able to have a good graph. Results: As you can see from the first graph without the logs, the relationship is that an increase in length causes an increase in time period. This was the prediction I made and also that the time periods would be significantly less than the preliminary due to a greater diameter of wire. I also added an R squared value to my log log graph; this gives me the strength of the correlation. With 1 being the highest, mine was 0. 9868, which shows very strong correlation.
Tuesday, January 21, 2020
cancer :: essays research papers
Topic: Cancer General End: To Persuade Specific Purpose: To persuade my audience that cancer is bad and they should eat a healthy diet. Central Idea: Cancer can be caused by smoking, drinking, sunburns, ect... and there are foods that can help stop cancer. I. What we eat really affects our risk of cancer.      A. 35% of all cancers have a nutritional connection.           1. When lifestyle factors such as smoking and sunbathing are included the risk can           be as high as 85%.                a. What we eat makes a big difference in our energy levels, our mood and                and even our self esteem.                b. Foods rich in protective factors such as fruits and vegetables, we are                doing something positive for our health and well being.           2. Antioxidants, anticarcinogens, and bioflavonoids repair damaged cells                a. The cells that are ruined by bad habits can be repaired by the                antioxidants, anticarcinogens, and bioflavonoids.                b. If too many cells are damaged and form a clump then cancer is formed                and these botanical factors will not be effective. II. Foods that are important for our health.      A. Foods that come from plant kingdom rather than the animal kingdom have many      protective botanical factors.           1. Many of the plant kingdom foods act as antioxidants, anticarcinogens, and           bioflavonoids.                a. Some foods rich in botanical factors are classified as phytonutrients.                b. Some phytonutrients include berries, dark green leafy vegetables, citrus,                fruits, legumes, and whole grains. B. Dietary fiber is important in cancer prevention.      1. The dietary fiber provides bulk to our diet and helps maintain a healthy colon.           a. Most Americans eat about 10 grams each day but this is half of what is ideal.           b. Dietary fiber is found in whole grain cereal, breads, pastas, beans, leafy           vegetables, fruits, nuts, and seeds. C. Fish can be protective against cancer.      1. Oily fish such as salmon, herring, mackeral, halibut, and tuna contain oils rich in
Monday, January 13, 2020
The Catastrophe of Chernobyl Nuclear Power Plant
On April 26 1986, the reactor Unit 4 at the Chernobyl nuclear power plant was not working properly. When workers tried to fix this problem in reactor 4 by shutting down the its power regulating system and its emergency safety systems, this caused the most serious and dangerous accident in the history of nuclear power generation. The Chernobyl accident released large amounts of radioactive materials into in the atmosphere, which were carried by air currents. Soon after this catastrophe, these radioactive materials were spread by the wind over many countries, which polluted their atmosphere. The release of radioactivity had a deadly effect on people's health and the environment; thus, before building such a plant, safety and emergency procedures must be guaranteed. The radioactive materials, which have been released from the accident, affected people's health for several years. The Russian government admitted the release of radioactivity, when the Swedish monitoring stations reported abnormal high levels of wind transported radioactivity as clarified by the International Atomic Energy Agency (IAEA). The government had to evacuate many areas and declare it as a †Forbidden zone †to protect people from radioactivity. Initially the accident caused the death of 32 people(B. Hummer,Nils â€Å"Chernobyl the accident†– http//:bcf. usc. edu/meshkati/chernobyl. html). The radioactive materials released from this accident are 200 times as much radioactivity as the Hiroshima and Nagasaki explosions (Dahl,Birgitta â€Å"The Chornobyl Nuclear Disaster†http//:scf. usc. edu/~melan). Its human death losses and the amount of the radiation released into the environment, raised a large number of problems not only for the treatment of severely exposed persons, but also The decisions that had to be taken considering the population. Thus, the number of people who were suffering from cancer was increasing and the number of thyroid cancers among children also increased in the most affected area: Belarus, Ukraine and Russia (Encyclopedia of Britannica online). Indeed, for several years, babies were born deformed and thousands were suffering from illnesses and cancer (which takes 8 to 10 years to appear), scientists and doctors were alerted because after only four years thyroid cancer increased much more than their expectations and its growth was more quickly than they expected and its pattern was different from the patterns known till now (Specter,M. Willy â€Å"The Three Mile Island and Chernobyl nuclear power accidents†`The New York Times`, Sunday march 31,1996). All these factors have increased diseases among the people living in the exposed area and the workers involved in clearing the site after the accident. In my opinion, it is extremely difficult to imagine the psychological effects of Chernobyl accident on the people who experienced it. In addition, this emotional stress and other psychological factors are the main possible cause of people's illnesses after the accident and in the future. The radiation did not only affect people's health but it polluted the environment and the territories beside the reactor. The area beside Chernobyl was heavily polluted because 70% of the radioactive substances fell on it (Encyclopedia of Britannica online). As stated by Najmedin Meshkati, a nuclear scientist; â€Å"The most dangerous thing was the food pollution (cesium, strontium, plutonium and americium) in milk and meat products are with concentration several hundred times higher than pre accident levels and often above the permitted levels and it will not disappear before 300 years†. Although, people know that these regions are heavily polluted and that meat and milk products have accumulated high quantities of radioactive substances, more than 1. 8 million people are still living there (Specter,M. Willy â€Å"The Three Mile Island and Chernobyl nuclear power accidents†`The New York Times`, Sunday march 31,1996). They drink radioactive fluids, eat radioactive substance (cesium131) will stay in the food and liquids and will not disappear completely before 300 years†. The consequences of these substances will not be noticed but after many years and it will not only affect the present generation but also the future generation. To insure maximum safety, emergency systems should be guaranteed before building any nuclear power plant. Thus, authorities must not ignore the possibility of the occurrence of an accident. The failure of workers to identify the problem between the systems to insure safety, and their failure to cooperate with each other is unacceptable. Workers must be trained to deal with real emergency situations in order to respond fast and to control it. However, after Chernobyl, solutions to insure the safety of large-scale technological systems have fallen into the categories of management and cost control (B. Hummer,Nils â€Å"Chernobyl the accident†-http//:bcf. usc. edu/meshkati/chernobyl. html). The cost to clean up the mess caused by the nuclear power plants are much more expensive than to install a new emergency system. Thus, the cost to maintain safety is negligible compared to the cost, which they have to pay if an accident happened. Moreover, authorities must be strict concerning the regulations of nuclear power plants. Many improvements in radiation protection and emergency preparations have been made, possible by the Chernobyl experience (Encyclopedia of Britannica online). The lessons drawn from the Chernobyl accident are valuable: human's life is precious. Thus, human must learn from their mistakes and know how to prevent their happening especially if these mistakes may cost innocent people's lives. An accident such as the catastrophe of Chernobyl is a descrase for humanity, that's why we cannot afford such mistakes again. Because some mistakes are unforgiving.
Sunday, January 5, 2020
Using Three Search Techniques For A Comprehensive And...
Aveyard (2014) recommends for a comprehensive and systematic search to use three search techniques; ïÆ' ± An electronic search of databases. ïÆ' ± A hand search from the reference list of published literature identified from the electronic search. ïÆ' ± An author search. The author undertook an electronic search were used to collect the literature. Three electronic databases were used; Cumulative Index to Nursing and Allied Health Literature (CINAHL), Medline and PsychInfo. These three databases were chosen as they are often used by nurses, allied health professionals, researchers, students and nurse educators to research their subject area (Aveyard, 2014). To make the search more effective and efficient, the advanced search was used in all three databases. Utilising the advance search setting options over the basic search setting allows the search to be made more specific (Aveyard, 2014, Moule Goodman, 2009). For an electronic search to be successful it is important to find the right key words or concepts required to retrieve the journal articles as journal articles are indexed and entered onto the databases using keywords (Aveyard, 2014). The keywords for this literature review derived from the research question and synonyms words (Schneider, Elliott, LoBiondo-Wood and Haber, 2004). The keywords identified and retrieved used a combination of the following keywords; CPR, cardiac arrest, cardiopulmonary resuscitat*, famil* and family carer*. The keywords family , witnessedShow MoreRelatedThe Need Of Integrating Lean And Six Sigma2223 Words  | 9 Pagescombination of two popular process improvement methodologies. What companies have found out is that their results are much greater using the Lean Six Sigma methodology instead of Lean or Six Sigma individually. 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