French Passive Constructions

Passive constructions are those in which a verbs action is performed on the subject, rather than the subject performing the action as in active (normal) constructions. The passive voice is the most common French passive construction, but there are a couple of others to watch out for as well. Other French Passive Constructions Passive Infinitive: Even though the French infinitive translates as to verb, the French infinitive sometimes needs to be preceded by a preposition. This is the case with the passive infinitive, which is commonly used with indefinite and negative words, such as Il ny a rien à   manger - Theres nothing to eat.Passive Reflexive: In the passive reflexive construction, a normally non-reflexive verb is used reflexively in order to express the passive nature of the action, as in Ça se voit - Thats obvious.Reflexive Causative: The reflexive causative (se faire infinitive) indicates something that happens to the subject, either per someone elses implied action or wish or unintentionally. Passive Reflexive in Detail In French (and English) it is preferable to avoid the passive voice. French has numerous constructions which are commonly used in place of the passive voice, one of which is the passive reflexive. The French passive reflexive is used in place of the passive voice in order to avoid naming the agent of a verb. The passive reflexive is formed with a noun or pronoun, then the reflexive pronoun se, and finally the appropriate verb conjugation (third-person singular or plural). In essence, this construction uses a non-reflexive verb reflexively in order to demonstrate the passive nature of the action. The literal translation of the French passive reflexive (something does something to itself) is strange to English ears, but its important to recognize this construction and understand what it actually means. Ça se voit. - Thats obvious.Ça saperà §oit à   peine. - Its hardly noticeable.Cela ne se dit pas. -  That isnt said.Ce livre se lit souvent. - This book is often read.Comment se prononce ce mot  ?  - How is this word pronounced?Comment à §a sà ©crit  ? (informal) - How is that spelled?Un homme sest rencontrà © hier. - A man was found yesterday.Un coup de tonnerre sest entendu. - A crash of thunder was heard.Les mà »res ne se vendent pas ici. - Blackberries are not sold here.Ce produit devrait sutiliser quotidiennement. - This product should be used daily.

High Cost of Healthcare Essay example - 1421 Words

There is no denying the fact that the cost of health care in the United States has been on a constant rise than the wage of the employees that pay to have access to better healthcare. There is the general fear among these employees that if the rising cost of the health care is not brought under control, there will come a time, and some analyst think, the time is already here, when those employees will not be able to afford health care for themselves and their families. This fear of the unknown is particularly evident among those closer to retirement. Employers of labor have for quite sometimes now, been shifting the burden of the high cost of affordable health care to their employees, and that has significantly reduced employee standard of†¦show more content†¦Bureau of Labor Statistics, 2010). The higher cost of affordable Health care is also eroding the ease with which to afford other insurance that covers about 30 percent of Medicare enrollees ‘expenses. In 2005, about 89 percent of beneficiaries obtained such additional coverage, including through former employers (33 percent), medical policies (25 percent), Medicare advantage plans (13 percent), Medicaid (16 percent), or other programs (1 percent) (MedPAC). These supplemental insurance programs were all very helpful at the onset, but with the passage of time and as health care costs continued to rise, employers are finding it difficult to support these programs and as a consequence, a greater number of these employers are either reducing the benefit or eliminating these benefits especially those that affects their retirees thereby increasing the cost of these supplemental insurances. The Impact on Employees Most health care analyst believes that health benefits provided by employers are provided as part of the overall compensation paid to workers. Because of the rising cost of the health care benefits, employers’ shares ofShow MoreRelatedThe High Cost Of Healthcare1484 Words   |  6 PagesThe high cost of healthcare continues to rise and many in the United States are optimistic for health information technology to reduce and improve our current situation. Health IT encompasses a broad array of new technologies designed to manage and share health-related information. When properly implemented, these systems can help coordinate patient care, reduce medical errors, and improve administrative efficiency. Therefore, implementing a Regional Health Information Organization (RHIO) willRead MoreFactors That Lead To The High Cost Of Healthcare1166 Words   |  5 PagesThe cost of medical care is on the rise, and the excessive nation spending on the healthcare reaches its record high. The high cost of medical services, drug prices, insurance cost, are contributing factors that leads to the shocking $2.6 trillion spent by the United States on the healthcare. The many factors that contribute to the high healthcare cost affect the employee practices on healthcare today. Research shows that less than 50 percent of companies offer health insurance to their employeesRead MoreThe High Cost of Healthcare in the United States1167 Words   |  5 Pageshealth care, cost is one of the biggest problems. Something needs to be done in order to make it possible for patients, families, and businesses to be able to afford health care. US does not always spend health care dollars in the most productive way. The cost of cancer treatments alone can cost up to hundreds of thousands of dollars, and the only way to pay for that is to raise the cost of the insurance to the patients. Cost is defined as the â€Å"price† of healthcare. The â€Å"price† or cost can come fromR ead MoreWhy Are U.S. Healthcare Costs So High?4536 Words   |  19 Pagesï » ¿ Why Are U.S. Health Care Costs So High? Overview of the High Cost of Health Care 12/9/2013 Alaska Pacific University MBA 63600 Health Service Systems and Policies Fall 2013 Why Are U.S. Health Care Costs So High? According the Department of Health and Human Services, total health care spending in the U.S. reached $2.3 trillion in 2008, or $7,681 per person. As a share of GDP, healthcare expenditures set a new record of 16.2 percent. That’s double the 8.1 percent share of GDP inRead MoreWellness Incentives and the High Cost of Healthcare Essay2009 Words   |  9 PagesHealthcare and wellness are important to every American, business and to our federal government’s bottom line. Sharon (2010) stated, â€Å"Staying healthy reduces the demand for health care. According to the Department of Health and Human Services, medical care for persons with chronic disease accounts for 75% of the dollars spent as a nation on medical care. Today’s most serious and expensive health problems are caused, in large part, by poor lifestyle choices: tobacco use, diets high in fat andRead MoreEconomic Factors Influencing High And Growing Healthcare Costs851 Words   |  4 PagesFactors inf luencing high and growing healthcare costs in the US The cost of health care in the United States continues to rise. National healthcare expenditures totaled over $2.9 trillion in 2013, equating to $9,255 per capita (Centers for Disease Control and Prevention [CDC], 2015). This is a consequence of both private and government healthcare financing mechanisms including: high unit prices, market power, specialized medicine, medical malpractice, private health insurance costs, ill populationsRead MoreThe Health Care Of Healthcare1339 Words   |  6 PagesHealthcare is a widely talked about issue in today’s society. After all, a factor of whether or not we vote for a presidential nominee is whether or not they support free healthcare, or have an effective healthcare reform. Out of thirty-three developed nations, thirty-two have universal health care, with the United States being the exception. A big question has been why does this nation’s healthcare cost so much, but the American people are not seeing their investment go to e ffective use. In healthcareRead MoreThe Economics of Healthcare958 Words   |  4 PagesThe Economics of Healthcare 1) In a traditional economic market, basic rules of supply and demand create a variance in price and, depending on the situation and how the market is perceptually framed, a variance in the products or services being offered in the market (Prasch, 2008). These variances create and/or are created by relationships between consumers and producers, and an implicit agreement between these two basic parties regarding the value of a good or service is reached simply by determiningRead MoreMedicare Is A Popular Choice Of Insurance Coverage1406 Words   |  6 PagesThe US triumphs by spending about 17 percent of its Gross Domestic Product on healthcare, making it the largest percentage of any country in the world. The government provides assistance in healthcare to many people, whether it be Medicare or Medicaid. Employers are the main source of health insurance in the United States, many offering their own health insurance plans that the employee can choose from. The most common types of he alth insurance are Medicare, Medicaid, Obamacare, or a private insuranceRead MoreQuestions On Types Of Payment1325 Words   |  6 Pagesmonthly fee for services instead of a separate charge for each visit or service under the network healthcare system. The monthly fees remain the same, regardless of types or levels of services provided. The reimbursement amount is according to copay and deductible detail in the contract. With an HMO plan, individuals or employers must select a Primary Care Physician (PCP) from a network of local healthcare providers under the HMO plan. HMO beneficiaries must arrange and visit their PCP first for the

Porter s Five Forces Model - 1539 Words

Porter s Five Forces Model Introduction The cosmetic industry is influenced by a wide range of factors that affect market growth and profits for businesses. The cosmetic industry has continued to record a substantial strong growth over the years and developed as one of the industries holding the highest potential for further development and growth. The market characteristics can reduce or increase the chances of success for new market entrants (Porter, 2008). Using Porter’s five forces model, businesses can be able to analyze the market and determine its attractiveness for investments. A major concern in health care is the quality. The purpose of this paper is to analyze the market attractiveness for a new cosmetic surgery clinic in†¦show more content†¦The industry has also recorded growth in the development of new customer segments. For instance, the desire to look young has increased the demand for male cosmetic surgery by 327% between 1997 and 2015 (Business Wire, 2016). The use of cosmetic surgery is a lso expected to increase going by the popular trends in media. The high demand for cosmetic surgery services is also demonstrated by the development of cosmetic surgery tourism. As the demand for cosmetic surgery remains high, the existing market players are unlikely to engage in aggressive market tactics such as price wars. New Market Entrants There are various market barriers that are likely to affect the potential of growth for new market entrants. New market entrants are likely to experience challenges with product or service differentiation. Product differentiation is achieved through brand recognition and is crucial in creating customer loyalty. Brand recognition is an important barrier for new entrants because of high emphasis on quality in the cosmetic industry (Gaynor, 2007). Quality of services and products is a major component of competition in the industry. New market entrants may be forced to spend a lot of resources in brand differentiation activities so that to gain customer loyalty. It might take time before the new business is able to overcome the customer loyalty towards the existing competitors. The new business willShow MoreRelatedThe Porter s Five Forces Model1281 Words   |  6 PagesAbstract The Porter s Five Forces model, which was named after Michael E. Porter, identifies and analyzes five competitive forces that shape every industry, and helps determine an industry s weaknesses and strengths. These forces are: †¢ Competition in the industry; †¢ Potential of new entrants into the industry; †¢ Power of suppliers; †¢ Power of customers; †¢ Threat of substitute products. It is commonly used to identify an industry s structure to determine corporate strategy. Porter s model can beRead MorePorter s Five Forces Model Essay1602 Words   |  7 PagesPorter s Five Forces model (PFF) is a powerful instrument that can be utilized by companies to investigate its situation and identify its industry s competitors. Analyzing industry will help any business in determining the competitive strength and weaknesses. By using PFF model, investors can gain valuable information regarding what the actual factors that affect the organization s profitability (Evans Neu 2008). This paper will analyze the Cola Wars case study based on the PFF model, and theRead MorePorter s Five Forces Model1611 Words   |  7 PagesPorter’s Five Forces In order to further figure out the failure of GM in Korea, we decided to analyse it from industrial perspective. The five forces model, which was developed by the Harvard professor Michael Porter, is going to be applied to the case. Porter’s five force model demonstrates that the Threat of New Entrant, the Threat of Substitute Products or services, the Bargaining Power of Buyers, the Bargaining Power of Suppliers and the Rivalry among the Existing Competitors are the forces thatRead MorePorter s Five Forces Model1137 Words   |  5 PagesThe next facet of the Porter’s Five Forces model, the bargaining power of suppliers, has a low to medium level of influence in the automotive industry. Suppliers can be easily replaced if an automotive producer is unhappy with the quality or price of their product. However, suppliers can have catastrophic effects on an automotive producer when their products fail and need to be recalled. For example, Firestone produced faulty tires equ ipped to the Ford Explorer which caused over 250 deaths, billionsRead MorePorter s Five Forces Model Essay1793 Words   |  8 PagesPorter’s Five Forces Model for the ACA helps explain how the system is currently being utilized in an unforeseen manner. (1) Competition in the industry is the private insurance, but in the unique world of healthcare, the competition does not infringe upon each other as conventional competition would. Private insurers have agreed to participate in the government’s exchange in return for more customers, but the premiums that new customers would pay are not conducive to profitability by the participatingRead MorePorter s Five Forces Model Analysis Essay2575 Words   |  11 Pages PORTER S FIVE FORCE MODEL ANALYSIS Name: Institution: Course: Date: Porter s Five Forces Model Analysis Introduction Porter’s five forces model was developed by Michael Porter in 1980 as a technique for industry analysis. An industry consists of a group of firms which are involved in the production of commodities which are close substitutes for one another. Essentially the five forces model provides corporations with a means of analyzing their fellow competitors within the market (PorterRead MoreAnalysis Of Porter s Five Forces Model1757 Words   |  8 Pagesand profits. Why is this so? FIVE FORCES MODEL Until recently, Porter’s Five Forces Model was the dominant theory applied to factors driving competitive forces in an industry. It hypothesizes that the level of competitive intensity within an industry arises from five specific sources in determining attractiveness of an industry to potential entrants. Porter developed Five Forces Analysis in response to SWOT analysis, a model he found too vague. In this economic model, while rivalry between competingRead MoreCase Study : Porter s Five Forces Model1153 Words   |  5 PagesORGANIZATION-EBAY Abstract Porter sFiveForce Porter s Five Forces Model is a critical instrument to break down an outer aggressive environment of the business. The model incorporates threat of entry, the threat of rivalry, the threat of suppliers, the threat of purchasers and threat of substitutes. How the five forces analysis reveal about the nature and strength of the various competitive pressures eBay faces Threat of Entry This business is an Internet-driven administration industryRead MoreHow to use porter s five forces model2243 Words   |  9 Pages7/22/2015 How to use porter s five forces model ïÆ'‰ (http://www.smartinsights.com)  Sign in (/wp-login.php) Become a member (/membership/) Resources (/digital-marketing-advice/) Blog (/blog/) About (/about/) Contact us (/contact-us/) How to use Porter’s five Forces NOVEMBER 18, 2013 MARKETING MODELS (HTTP://WWW.SMARTINSIGHTS.COM/MARKETING-PLANNING/MARKETING-MODELS/) (http://www.smartinsights.com/marketing-planning/marketing-models/porters-five-forces/?share=twitternb=1) (http://www.smartinsightsRead MoreCase Study : Porter s Five Forces Model1132 Words   |  5 Pages Organization-Ebay Institution: Name: â€Æ' Abstract Porter sFiveForce Porter s Five Forces Model is a critical instrument to break down an outer aggressive environment of the business. The model incorporates threat of entry, threat of rivalry, threat of suppliers, threat of purchasers and threat of substitutes. How the five forces analysis reveal about the nature and strength of the various competitive pressures eBay faces Risk of Entry This business is an Internet driven organization

Wireless Security Wireless Network Essay - 1089 Words

Wireless Security Overview Wireless networks serve as the transport mechanism between devices and among devices and the traditional wired networks (enterprise networks and the Internet). Wireless networks are many and diverse but are frequently categorized into three groups based on their coverage range: Wireless Wide Area Networks (WWAN), Wireless Local Area Network (WLANs), Wireless Personal Area Network (WPAN )and etc. WWAN includes wide coverage area technologies such as 2G cellular, Cellular Digital Packet Data (CDPD), Global System for Mobile Communications (GSM). WLAN, representing wireless local area networks, includes 802.11, HiperLAN, and several others. WPAN, represents wireless personal area network technologies such as Bluetooth and IR All of these represent potential threats in wireless networks as well. However, the more immediate concerns for wireless communications are: †¢ Denial of service †¢ Malicious hackers †¢ Theft of service (Identity theft / MAC spoofing) In wireless security, information must be protected from unauthorized, unanticipated, or unintentional modification. Security requirements include the following: †¢ Authenticity—A third party must be able to verify that the content of a message has not been changed in transit. †¢ Nonrepudiation—The origin or the receipt of a specific message must be verifiable by a third party. †¢ Accountability—The actions of an entity must be traceable uniquely to that entity. As wireless communication and theShow MoreRelatedWireless Network Security1602 Words   |  7 PagesPaper CNT4514 Wireless Vulnerabilities The world of wireless networks as we all know is one of the most rapidly growing areas in our world today. With the massive amount of data that is going on, â€Å"the cloud† the security of all of our data is questioned. As well with so many of our day to day tasks relying on our wireless capabilities it make you wonder how safe is it to rely so heavily on something. We have to ask the questions what are the key vulnerabilities of wireless networks and even justRead MoreQuestions On Wireless Network And Security1402 Words   |  6 Pages Assignment-1 MN603 Subject Wireless Network and Security Teacher Biplob Rakshit Ray Name : Loveneet Singh Dhanjal ID: MIT130071 Contents 1) Introduction 3 2) Massive MIMO architectures 3 a. V-BLAST 3 b. Array Architecture 4 3) Uses of massive MIMO to achieve convergence of wireless networks 5 a. Spatial multiplexing 6 b. Pre-coding 6 4) Existing Technologies 6 a. WiMAX 6 b. 3G 6 c. 4G LTE 7 5) Recently proposed techniques in the literature 7 5G 7 6) RelevantRead MoreImplementation of Security for Wireless Network3538 Words   |  15 PagesImplementation of Security for Wireless Network R.Sridevi (Asst.Prof) Department of Computer Science PSG College of Arts amp; Science Coimbatore, TN. srinashok@gmail.com Abstract -This paper addresses the internal and the external security challenges in organizations that implements wireless networks. Distributed security is designed to provide a more secure data communication among faculty members, staff and students. A description of the technique used to protect and keep PC s up andRead MoreWireless Network Security : Abstract1520 Words   |  7 Pages Wireless Network Security Abstract This is the study over the wireless network security. As the wireless communication has the different way of physical transport compared to wire environment of communication thus we have to use different measure to secure a network in wireless environment. Wireless networking has more security threats and vulnerabilities and we must have an effectiveRead MoreWireless Sensors Networks Security1991 Words   |  8 Pagessystems (MEMS) and wireless networks are opening a new domain in networking history. Sensors; often called smart dust are low cost small tiny devices with limited coverage, low power, smaller memory sizes and low bandwidth, will play a key role in collecting and disseminating data from the fields where ordinary networks are unreachable for various environmental and strategical reasons. There have been significant contributions to overcome many weaknesses in sensor networks like coverage problemsRead MoreThe Security Issues Revolving Around Wireless Networks1668 Words   |  7 PagesIntroduction Wireless computer networks have become very common in the past several years. The convenience with which computer users can utilize internet connections, without having a network cable attached to their computers, makes wireless networks extraordinarily popular in today’s on-the-go society. Homes, offices, and public businesses (e.g., hotels, coffee shops, restaurants, etc.) all frequently have active wireless computer networks. As is the case with hard-wired computer networks, security isRead MoreSecurity Issues Of Wireless Sensor Networks1286 Words   |  6 PagesSecurity issues in Wireless Sensor Networks What the security issues are related to Wireless Sensor Networks Name:Sandeep Kumar Pulijala Student ID:S0261345 Teacher:Erin Class:DEA3 Central Queensland University What the security issues are related to Wireless Sensor Networks Wireless sensor networks are very important in everyday life. This new technology is exciting with unlimited potential for numerous application areas includingRead MoreEssay about Wireless Network Security – How Secure Is It?6131 Words   |  25 PagesWIRELESS NETWORK SECURITY – HOW SECURE IS IT? by Chris Bradley ITT Technical Institute Information Systems Security student November 23, 2010 Dr. French: This report on â€Å"Wireless Network Security† is submitted in accordance with your assignment for November 23, 2010. Sincerely, Chris Bradley ABSTRACT For this project, I asked the question â€Å"is wireless network protection truly safe?† My literature search led me to conclude that, if consumers use the most up-to-dateRead MoreNew Dell Sonicpoint Series Enhances Wireless Network Security Solution994 Words   |  4 PagesCorporate Blog, The power to do more. The blog is entitled â€Å"New Dell SonicPoint Series Enhances Wireless Network Security Solution† †¢ Audience: Prospective Employers (Business Organizations) and their employees such as IT professionals, students, people working in schools, universities, hospitals etc. The paragraphs use facts to explain the benefits of SonicPoint Series: â€Å"Coupled with the increase in wireless devices is the use of bandwidth intensive applications including video and voice, HD multimediaRead MoreSecurity Wireless Sensor Networks By Mohd Faraz Uddin1127 Words   |  5 Pages SECURITY IN WIRELESS SENSOR NETWORKS by Mohd Faraz Uddin Submitted in partial fulfilment of the requirements for the degree of MASTER OF ENGINEERING Major Subject: Internetworking at DALHOUSIE UNIVERSITY Halifax, Nova Scotia January, 2016  © Copyright by your Mohd Faraz Uddin, 2016 Dalhousie University Faculty of Engineering Internetworking The undersigned hereby certify that they have read and award a pass in INWK 6800 for the seminar project entitled

Borohydride Reduction Free Essays

John Heger CMY 211 Lab Section 13 11-30-2011 Borohydride Reduction of Vanillin to Vanillyl Alcohol Introduction: The purpose of this lab was to reduce vanillin to vanillyl alcohol. This lab report recaps the procedure and results of the lab. The chemical process studied in this lab was reduction, the process of reducing the number of bonds to oxygen and increasing the number of bonds to hydrogen. We will write a custom essay sample on Borohydride Reduction or any similar topic only for you Order Now Other chemical processes included in the lab were recrystallization, melting point, and extraction. Procedure: Preparation of Vanillyl Alcohol 2. 5 mmol of vanillin were dissolved in 2. 5 mL of 1 M NaOH solution in a 25 mL Erlenmeyer flask. The flask was swirled to produce a homogeneous yellow solution. The flask was swirled in an ice-water bath for 1-2 minutes and the solution was cooled to approximately 10Â °C. 1. 95 mmol of NaBH4 was added while the solution was constantly swirled. It was added in three to four portions over a period of 3 minutes. The solution was allowed to stand undisturbed for 30 minutes at room temperature. After the time period, the flask was cooled in an ice-water bath and 3 M HCl was added dropwise with swirling. HCl was added until the pH of the solution was distinctly acidic to pH paper. The solution was gently cooled and the side of the flask was gently scratched with a glass rod to induce recrystallization. The crude product was suction filtered using a Buchner or Hirsch funnel and was washed with three small portions of cold water. The crystals were allowed to air dry for several minutes while suction continued to eliminate excess water. The crude product was recrystallized from ethyl acetate. The dried crystals were weighed and a melting point was obtained. Results: Table 1: Experimental Data Table Initial Mass of Vanillin| 0. 3843 g| Final Mass of Vanillyl Alcohol| 0. 2467 g| Melting Point Range of Vanillyl Alcohol| 75-90Â °C| Percent Yield| 63. 99 % yield| Discussion: The purpose of this lab was to reduce vanillin to vanillyl alcohol. The mechanism of the lab involved reduction. Sodium borohydride was used to reduce the aldehyde on the vanillin molecule, which left the oxygen with a negative charge. Feature Article Relative Rates:Â  Free-Radical Bromination HCl then reacted with the negative oxygen on vanillin, and the oxygen then became protonated, which made another alcohol on the benzene ring. The melting point range obtained for vanillyl alcohol was between 75-90Â °C. The actual melting point was 115Â °C, which was approximately 25 degrees higher than the experimental values. The reason for this melting point difference can be attributed to impurities that developed throughout the procedure. The percent yield from the original sample was 63. 9%. A decent percentage of the original sample was lost throughout the reduction process of vanillin to vanillyl alcohol. Conclusion: Vanillin was reduced to vanillyl alcohol which obtained a melting point of 75-90Â °C. The percent yield from the original sample was 63. 99%. The mechanism involved the reduction of vanillin to vanillyl alcohol, which increased the number of bonds to hydrogen and decreased the number of bonds to oxygen by the reduction of a carbonyl. How to cite Borohydride Reduction, Essay examples

Aircraft Propeller Essay Example For Students

Aircraft Propeller Essay Theaircraft propeller looks like a simple mechanism to the uneducated individual. To the educated, an aircraft propeller represents the highest sophistication inaerodynamics, mechanical engineering and structural design. This report willtouch on the history of the propeller, from early pioneers/experiments,advancement during/after the war, all the way up to current applications of thepropeller. The creation of the propeller can be traced back to Leonardo daVinci. Da Vincis helical screw helicopter is believed to be theancestor of the air propeller and the helicopter rotor. The first idea of apropulsive airscrew, however, belongs to J.P. Paucton, a French mathematician. Paucton envisioned a flying machine that had two airscrews, one for propulsionand the other for sustaining flight. The idea of using an airscrew forpropulsion was utilized during the late 1700s to early 1800s. Only afterexperimentation did the inventors conclude that more propulsive power could beobtained by merely straightening out the surface of the airscrew blades. Attempts to utilize the straight blade propeller were made by balloonists. These contraptions were quite strange and hardly fulfilled their purpose ofactually propelling the balloon. The basic propeller had evolved from the simpleconcepts of da Vinci, and was slowly becoming an effective means of aerialpropulsion. To reach the next plateau of flight an increased knowledge of thepropeller would be needed, and the mysteries of the propeller and mechanicalpower would need to be solved. These substantial tasks remained for aviationspioneers to tackle during the 19th century. Throughout the 19th century,aviation pioneers explored and tinkered with the concepts of flight to design aviable airship. Some pioneers tried to transform the balloons into navigablecigar shaped airships by experimenting with sails, propellers, and paddlewheelsbut all produced limited results. Other experimenters, who were convinced thatman flight should have wings, worked to establish basic principles inaerodynamics, flight stability and control, as well as propulsion. Controlledmechanica l flight came on August 9, 1884. Charles Renard and A.C. Krebs flew theairship La France on a closed circuit from Chalais-Meudon to Villacoublayand back in 23 minutes. The airship La France was powered by a 9horsepower electric motor that drove a 23ft diameter propeller and reached aspeed of 14.5 mph. This flight was the birth of the dirigible, a steerable,lighter-than-air ship with adequate propulsion. Another important milestone inaviation, was the understanding of aerodynamics. Sir George Cayley, a Britishtheorist, was acclaimed as the father of aerodynamics. He established a solidfoundation of aerodynamic principles that were essential to the success of otherpioneers. In 1875, Thomas Moy created a large model that had twin 12ftpropellers with 6 blades each! Interestingly enough these blades could beadjusted to produce maximum thrust under certain conditions, an earlyrecognition of the need for changing blade pitch. Without a doubt, the mostexpensive and spectacular project of it s time was that carried out by Sir HiramMaxim. His numerous experiments with propellers, culminated in the constructionof a huge, four-ton biplane in 1890. This contraption was powered by two 180hpsteam engines that each drove propellers 17ft, 10inches in diameter and weighing135lbs. The two-blade propellers, inversely tapered and squared at the tips 5 ?ft wide, were made of American Pine, planed smooth, covered with glued canvasand stayed to the propeller shafts with steel wire to handle the high thrustloads. These massive propellers produced 1,100lbs of thrust each during fullpower while rotating at 425rpm. Maxims jumbo creation didnt last longhowever, it jumped the test track and suffered extensive damage. Hands down, themost influential aviation pioneers were the Wright brothers. They had concludedthat a propeller was simply a whirling wing, but didnt have the appropriateinformation to consult when comprehending the fundamental principles of bladeshape and motion. This dilemma m ade designing the propeller one of the Wrightbrothers most challenging problems. Despite the lack of previous information toconsult, the brothers were able to learn, through investigation and trial/error,that large propeller diameters would produce high thrust for a given powerinput. The brothers also determined that high torque produced by large, slowturning blades adversely affected the flying qualities (p-factor). On theirfirst aircraft, they utilized 8 ? ft propellers installed behind the wind tominimize airflow disturbance, incorporated counter-rotating propellers toeliminate the problems associated with torque, and gained thrust efficiency byreducing the blades rotational speed using a chain and sprocket transmission. .u76518150446036e9df8a4460d2e59268 , .u76518150446036e9df8a4460d2e59268 .postImageUrl , .u76518150446036e9df8a4460d2e59268 .centered-text-area { min-height: 80px; position: relative; } .u76518150446036e9df8a4460d2e59268 , .u76518150446036e9df8a4460d2e59268:hover , .u76518150446036e9df8a4460d2e59268:visited , .u76518150446036e9df8a4460d2e59268:active { border:0!important; } .u76518150446036e9df8a4460d2e59268 .clearfix:after { content: ""; display: table; clear: both; } .u76518150446036e9df8a4460d2e59268 { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u76518150446036e9df8a4460d2e59268:active , .u76518150446036e9df8a4460d2e59268:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u76518150446036e9df8a4460d2e59268 .centered-text-area { width: 100%; position: relative ; } .u76518150446036e9df8a4460d2e59268 .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u76518150446036e9df8a4460d2e59268 .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u76518150446036e9df8a4460d2e59268 .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u76518150446036e9df8a4460d2e59268:hover .ctaButton { background-color: #34495E!important; } .u76518150446036e9df8a4460d2e59268 .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u76518150446036e9df8a4460d2e59268 .u76518150446036e9df8a4460d2e59268-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u76518150446036e9df8a4460d2e59268:after { content: ""; display: block; clear: both; } READ: Argumentative Essay About TechnologyThe Wright brothers propeller was 66% efficient which was much higher thatany other propeller of the time. The foundations of a disciplined approach topropeller design evolved soon thereafter. With the advancements and refinementsmade by early inventors, engineers could use those test results to designpropellers with better performance and structural reliability. Theseadvancements led to the development of the first generation of well-designedpropellers. One of the first designs was the Integrale, developed byLucien Chauviere, the worlds first industry standard propeller manufacturer. By 1910, the number of propeller producers multiplied, and numerous advancementswere made. While most of the manufacturers were focusing on wooden propellers, afew visionaries were experimenting with metal propellers and variable pitchblades. Geoffrey deHavilland, an English engineer, tested propellers whosealuminum blades could be adjusted to change their angle. At the same time,German pioneers Hugo Junkers and Hans Reissner experimented with lightweightmetal propellers. The first U.S. propeller production facility was the RequaGibson Company founded in 1909, which was headed by Canadian engineer Wallace R. Turnbull. Turnbull tested and confirmed that the large, slow-speed propellersproduced higher thrust efficiencies than those compared with smaller, high-speedpropellers. More importantly, Turnbull confirmed the universal law ofaerodynamics: the efficiency of any aerodynamic device rises as the amount ofair it acts upon increases and the velocity of that air decreases. Thesetheories were expanded during WWI. The war brought much advancement to thepropeller. Stronger materials were created through bonding which madepropellers compatible with the larger, more powerful engines. Propellerbalancing techniques were developed, which greatly smoothed out the ride. Experiments with variable pitch blades were introduced as well. Two majorbreakthroughs occurred after the war: the once piece metal propeller, and theground adjustable pitch propeller. The metal propeller allowed operations in allclimates, whereas the wooden prop would fail in extreme conditions. The metalpropeller could be made thinner than a comparable wooden propeller, whichallowed for faster cruising speeds due to less drag from compressibility. Thinner blades also improved efficiency at higher speeds. The only drawbacks tothe early metal propeller were their weight and fixed pitch blade angles. Thedevelopment of the ground adjustable propeller was a major improvement. The bestpropeller of this kind at the time was the dural-blade ground adjustablepropeller. With this adjustable propeller, the pilot could choose whether or notthey wanted to have great takeoff performance or great cruise performance. In1927, the idea of changing the pitch of a propeller was taken one step furtherwith the development of the in-flight adjustable propeller. This gearshiftdevice allowed pilots to change the pitch angle in flight to get the bestperformance out of their aircraft during takeoffs and during cruise. One of themost interesting developments during this period was the introduction of apropeller that could feather. This greatly reduced prop drag and was amulti-engine pilots savior when one of his engines quit. Hamilton Standard,on their H ydromatic propeller, introduced the feathering blade. AfterWWII, the Hydromatic propeller was improved by Hamilton Standard to includefeatures such as reversible pitch, automatic synchronization, and electricalblade deicing. Many large propeller transports switched to this new system forits reliability and pilot friendly features. The age of the Turboprop brought afew changes to the propeller. Four bladed, wide chord, aluminum alloypropellers, were utilized by most turboprop transports because of theirdurability. Engineers designed wide, super-thin, hollow blades to increase theperformance of the aircraft at high speeds. Advanced applications of thepropeller are currently being experimented by Hamilton Standard. The new ideadeals with transport category aircraft and the introduction of the un-ductedfan. This design incorporates the reliability of the turbine engine, with theefficiency of a prop. Expected savings of 25% in fuel costs drive the ongoinginterest in this application. The design utilizes 8-10 thin but very wide,closely spaced, swept angle blades to propel an aircraft at speeds approachingthe speed of sound (mach .8). It will be interesting to see how the role of thepropeller develops as time goes on. This report has sparked my interest inpropellers. I have never researched this topic before and feel that Ivebenefited from writing it. I enjoyed researching the history of the propellerand its contributions to aviation milestones. Ive taken you, the reader,from the early experiments of da Vinci, the wooden props of the Wright brothers,the design of the variable pitch propeller, through the advanced concept of theun-ducted fan. I hope this report was as interesting to read as it was towrite.