Free Essays on Rotary Vs. Piston Engine

Nearly every car ever made uses one form of a four-cycle reciprocating engine. As with any engineering design the reciprocating engine has certain pro and cons. The rotary engine provides an alternative to the reciprocating engine while being similar enough to use much of the same mechanical principles. The purpose of any combustion engine is to create power by igniting a mixture of air and fuel in a controlled environment, or the engine block. There are three goals that the engine design needs to accomplish: how to get fuel and air into the combustion chamber, how to get extra power from the combustion, and how to remove the spent fuel and air from the chamber. This is done by what is know as the Otto cycle, which is composed of four strokes: the intake, compression, combustion, and exhaust. The reciprocating engine, or piston engine is composed of about forty simultaneously moving parts. Inside the cylinder there is a piston that is free to move up and down within the cylinder. There is also an intake valve on one side and an exhaust valve on the other. The intake valves opens, letting air and fuel into the chamber, and moving the piston downward. This is the intake stroke. The valves close, and the piston moves back upwards, shrinking the chamber and compressing the air fuel mixture. This is the compression stroke. The mixture is then ignited creating an explosion forcing the piston to move downward again. This is the combustion stroke, the only stroke that produces actual power. Once the piston reaches the bottom of the chamber the exhaust valves open, forcing the spent mixture or exhaust out of the chamber. The cycle is continuous, therefore the cycle will return to the intake stroke. This engine has two disadvantages. The only time the engine is gener ating power is when the piston is forced down by the combustion , this means that the piston must move up and down twice for each power stroke. The up and down ... Free Essays on Rotary Vs. Piston Engine Free Essays on Rotary Vs. Piston Engine Nearly every car ever made uses one form of a four-cycle reciprocating engine. As with any engineering design the reciprocating engine has certain pro and cons. The rotary engine provides an alternative to the reciprocating engine while being similar enough to use much of the same mechanical principles. The purpose of any combustion engine is to create power by igniting a mixture of air and fuel in a controlled environment, or the engine block. There are three goals that the engine design needs to accomplish: how to get fuel and air into the combustion chamber, how to get extra power from the combustion, and how to remove the spent fuel and air from the chamber. This is done by what is know as the Otto cycle, which is composed of four strokes: the intake, compression, combustion, and exhaust. The reciprocating engine, or piston engine is composed of about forty simultaneously moving parts. Inside the cylinder there is a piston that is free to move up and down within the cylinder. There is also an intake valve on one side and an exhaust valve on the other. The intake valves opens, letting air and fuel into the chamber, and moving the piston downward. This is the intake stroke. The valves close, and the piston moves back upwards, shrinking the chamber and compressing the air fuel mixture. This is the compression stroke. The mixture is then ignited creating an explosion forcing the piston to move downward again. This is the combustion stroke, the only stroke that produces actual power. Once the piston reaches the bottom of the chamber the exhaust valves open, forcing the spent mixture or exhaust out of the chamber. The cycle is continuous, therefore the cycle will return to the intake stroke. This engine has two disadvantages. The only time the engine is gener ating power is when the piston is forced down by the combustion , this means that the piston must move up and down twice for each power stroke. The up and down ...

NMSQT Why Should You Care

What Is the PSAT/NMSQT Why Should You Care SAT / ACT Prep Online Guides and Tips Have you heard about the PSAT or the National Merit program and are wondering what they are?Are you looking for ways to prepare for the SAT? Read this guide to learn what the PSAT/NMSQT is, what it tests, and how it can get you ready for the SAT and earn you money for college. What Is the PSAT/NMSQT? First of all, what do all those letters stand for? The full name is thePreliminary SAT/National Merit Scholarship Qualifying Test, often abbreviated to PSAT. So what is the PSAT? It's a standardized test that 10th and 11th graders can take, and about 3.5 million students choose to take it each year. The PSAT is used to determineeligibility and qualification for the National Merit Scholarship Program (which is what the "NMSQT" part of the name is for). It also serves as a practice test for the SAT, but be aware that you can't submit PSAT scores to colleges as your standardized test scores. What Sections Does the PSAT/NMSQT Include? The structure and content of the PSAT have been recently revised to reflect changes made to the SAT. There are three sections on the PSAT: Math, Reading, and Language and Writing. The total testing time of the PSAT is 2 hours and 45 minutes, and it includes 139 questions. This information is broken down more specificallybelow. Reading Section: 60 minutes to answer 47 questions Writing and Language Section: 35 minutes to answer 44 questions Math Section: 70 minutes to answer 48 questions What Material Do These Sections Cover? Reading Section The reading section tests students'ability to draw conclusions and make inferences from reading passages. The 47 questions arebased on three passages and two passage pairs (a passage pair is when a passage is paired with a chart, table, graph, or other passage, and the questions use information from both of those sources). The five passages/passage pairs will cover the following subjects: 1 on US/World Literature (with 9 corresponding questions) 2 on Social Studies/History (with 18-20 corresponding questions) 2 on Science (with 18-20 corresponding questions) Writing and Language Section The Writing and Language Section testsknowledge of grammar, usage, punctuation, and other English conventions. It does not include an essay. There are four passages/passage pairs in this section whichaddress topics related to careers, history/social studies, the humanities, and science. There are two categories of question in this section: 24 questions on Expression of Ideas 20 questions on Standard English Conventions Math Section The Math Section focuses on algebraic problems and tests ability to analyze and interpret data sets. For the first 25 minutes, a calculator is not allowed, but students are allowed to use a calculator for the last 45 minutes of the section. The questions are mostly multiple choice, but some (17-22%) will have grid-in answers. The topics tested in this section are: Heart of Algebra (linear equations and systems) Problem Solving and Data Analysis (quantitative literacy) Passport to Advanced Math (manipulation of complex equations) Additional Topics in Math (geometric and trigonometric skills) How Is the PSAT/NMSQT Scored? The PSAT has recently implemented a new scoring system. As of 2015, thescore range has been changed, and there will no longer be deductions for incorrect answers.Although the PSAT/NMSQT has a shared common score scale as the SAT, score ranges are not identical. The PSAT's total score range is 320-1520. The PSAT's range doesn'tgo up to 1600 like the SAT's does because the PSAT is a less difficult test than the SAT, and sincea perfect score on the PSAT does not necessarily indicate a perfect score on the SAT, having identical score ranges may have causedsome test takers to mistakenly believe that. There are two main section scores for the PSAT: the Math Score and the Evidence-Based Reading and Writing Score. Both of these sections havescore ranges of 160-760. The Evidence-Based Reading and Writing Score is based on the combined scores of the Language and Writing and the Reading sections. This means that the Math section accounts for half of your entire PSAT score. The PSAT also has three test scores for each of the three subject sections, Math, Reading, and Language and Writing, that range from 8-38. Additionally, within each of these three sections there are several subsections with scores ranging from 1-15. These subscores letexam takers see how well they scored in more specific areas and can help make future studying more effective. There are seven subscores in the following categories: Reading:Command of Evidence, Words in Context Writing and Language:Expression of Ideas, Standard English Conventions Math:Heart of Algebra,Problem Solving and Data Analysis, Passport to Advanced Math What Are the Benefits of the PSAT/NMSQT? How can taking the PSAT help you? There are three main ways: 1. Practice for the SAT The PSAT allowsyou practice taking a test very similar to the SAT, under real test conditions. It can give you an estimate of the score you'd get on the SAT, and you can also look at the section scores and subscores to see which areas you should study the most in the future. The PSAT is a great way to practice for the SAT and other standardized tests 2. Practice for Standardized Tests in General Even though the PSAT will prepare you most directly for the SAT, taking it can benefit anyone looking to get more practice taking other standardized tests, like the ACT. It can help you practice managing your time during a test, improve your critical thinking skills, and also give you an opportunity to seehow well you do under official testing conditions. 3. Potential for Scholarship Money Competition is tough, but students with top PSAT scores can get a significant amount of scholarship money.Of the roughly 1.5 million high school juniors who take the test, about 50,000 students with the highest total PSAT/NMSQTscores qualify for recognition in the National Merit Scholarship Program. About 34,000 of those students become Commended Scholars. The roughly 16,000 students with the highest PSAT scores in the country (partly based on which state you live in) become National Merit Semi-Finalists, and most of them (about 15,000) move on to become National Merit Finalists. Over $180 million in scholarship money is awarded annually to students who get high scores on the PSAT. About half of the National Merit Finalistsreceive a $2,500 National Merit Scholarship, renewable for up to four years. Many corporations offer scholarship money as well. In addition, many colleges offer scholarships to National Merit Commended Scholars, Semi-Finalists, and Finalists. Some schools even offer a tuition waiver, which can save you tens of thousands of dollars. If you're interested in learning more about the National Merit Scholarship program, check out our guide which provides tips to help you improve your chances of becoming a Semi-Finalist! Getting a National Merit Scholarship can really fill up your piggy bank Want to improve your PSAT score by 150 points? We have the industry's leading PSAT prep program. Built by Harvard grads and SAT full scorers, the program learns your strengths and weaknesses through advanced statistics, then customizes your prep program to you so that you get the most effective prep possible. Check out our 5-day free trial today: Who Should Take the PSAT/NMSQT? There are multiple groups who can benefit from taking the PSAT. This can include high school sophomores or juniors looking to get more practice for the SAT, especially under real test conditions, as well as studentswho want more practice taking standardized tests in general. If you are trying to decide between the SAT and the ACT, taking the PSAT may also helpful because you can getan estimate of your SAT score without worrying about it being sent to colleges if it is lower than you'd like. Juniors who are confident in their standardized test-taking abilities and want to try for National Merit recognition and scholarships should also consider taking the PSAT, as well as sophomores hoping to increase their chances of winning a scholarship next year by getting more PSAT practice. How Do You Sign Up for the PSAT/NMSQT? The PSAT is administered by high schools, so you will register through your school. The PSAT is taken in October of your junior year. You can also take the exam as a sophomore, however; you won’t be eligible for National Merit awards that year. There is alsoa test called the PSAT10, which is offered only for 10th graders in the spring. This is the same test as the PSAT/NMSQT, but it is for preparation purposes only and is not part of the National Merit Scholarship Program.Students who take the PSAT 10 in the spring can still take the PSAT/NMSQT in the fall. What's Next? Have you decided to take the PSAT and want to know how to prepare for it? Take a look at this guide to finding full-length PSAT tests and practice questions! Not a high school junior yet? Take a look at our guide to the PSAT 10, which is specially designed forsophomores. Interested in winning a National Merit Scholarship? We have a guide that gives step-by-step instructions to improving your chances! Want to improve your SAT score by 160 points or your ACT score by 4 points?We've written a guide for each test about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now: