Pharmacoeconomics Notes Essay

The Confessions is a work by Augustine that diagrams his corrupt youth and change to Christianity. Augustine composed it somewhere in the range of 397 and 401 while filling in as the minister of Hippo Regius. In his book, Augustine gives his very own record life from birth up to that point. He at that point expounded on different issues, for example, the production of the world, memory and time. A major fragment of the book is spent on Augustine’s admission of sins that he had battled with and how he had argued to God for redemption from those transgressions. Augustine expounds on his failure in carrying on with an unethical way of life. He laments having put stock in soothsaying and followed the Manichaean religion. He additionally expounds on how Nebridius convinced him that soothsaying was insidious and how St. Ambrose encouraged in his change to Christianity. The Confessions is at long last a location by Augustine to God in which he admits his wrongdoings, confidence, and acclaim. Augustine says that he composed the Confessions for â€Å"a individuals inquisitive to know the lives of others, however indiscreet to change their own.† Augustine knew that individuals wanted to chatter and look profoundly into the lives of others to perceive how they could talk down an individual and at last cause themselves to feel better. Augustine realized that his composing would have been examined however made it his motivation to come clean and show the provision of God in the life of a miscreant. He didn’t need anybody to think any preferred of himself over he really was. Another reason recorded as a hard copy Confessions was to make a quick security between his new Christian people group. His partners were suspicious of his agnostic impacted instruction just as his remaining as an ex-Manichee. He needed to tell them that he was dependable and he did that by putting in plain view the most noticeably awful and best of his life. Fundamentally, Augustine’s life turned into an open book for everybody to peruse and become more acquainted with by and by. Augustine could have additionally composed Confessions as an endeavor to get himself. He may have thought about his satisfaction in sex and the joys of this world to be an intolerable shortcoming and he expected to admit recorded as a hard copy that God alone was his genuine affection. Clearly Augustine is broken over his transgression and it is most likely something that devoured his brain. Getting this horrendous past behind him was absolutely critical and he did it through composing Confessions to God. The composing style with which Augustine composes the Confessions isâ amongst different things straightforwardly striking, empowering, and without regret. This is certainly not quite the same as present day journalists who attempt and mask their actual inward emotions while as yet attempting to compose with significant style. Augustine isn't attempting to keep down any piece of his life that he may be embarrassed about. It is an incredible opposite as he certainly commends the Lord and proclaims God’s enormity. Augustine perceives his place as a spot of residue that strives for a spot within the sight of omnipotent God who made the universe. He isn't afraid to compliment his Lord and consistently gives you an inclination that he isn't fulfilled until he discovers his rest in God. He is empowering all through his book as he passes on God’s reliability to him in any event, when he was profound into transgression. Regardless of what part of the book one peruses, the individual in question can generally relax because of the way that regardless of how far one runs from God, He is in every case in that spot sitting tight for us with great affection. Taking everything into account, Augustine is so centered around God, that he has no lament in sharing his accidents and announcing God’s pardoning. He realizes that he ran a long way from God however that God was in that spot the whole time. He feels very absurd and yet so appreciative for God’s ceaseless effortlessness. Augustine attests with enthusiasm that he needs to be filled by God and thus he can genuinely live.

Being productive over break

Being productive over break This post is delayed a few days due to publishing, but still relevant. Welcome back, everyone! I have to say, its great to be back, even though life is a bit busy! Part of what is helping me stay calm is the fact that I did a bit of work over break. First, let me acknowledge the fact that it can be hard to be productive over break. However, it certainly is possible, and youll thank yourself for your somewhat simplified life after break. If not everything is do on Monday, you dont absolutely have to do everything. Just begin doing something, and try to make as much progress as you can. Seriously, even just an hour of work a few days over break will help. Doing a little something over break will boost your confidence when you get back. Over break, I did some paperwork and half a project. Not too much, but it has made this week easier to handle! Sarah Class of 2018 I'm from Grand Rapids, Michigan. I'm majoring in Communication in the College of Liberal Arts and Sciences.

Meditation Essay - 4138 Words

Meditation is an age-old practice that has renewed itself in many different cultures and times. Despite its age, however, there remains a mystery and some ambiguity as to what it is, or even how one performs it. The practice and tradition of meditation dates back thousands of years having appeared in many eastern traditions. Meditation’s ancient roots cloud its origins from being attributed to a sole inventor or religion, though Bon, Hindu, Shinto, Dao, and later, Buddhism are responsible for its development. Its practice has permeated almost all major world religions, but under different names. It has become a practice without borders, influencing millions with its tranquil and healing effects. Western medicine has recently†¦show more content†¦Regardless of a new capitalism, which has erupted around meditation, the practice has provided a mental oasis to millions of people strained and made anxious by the stresses of modern life. Meditation is the practice of â€Å"bringing the mind home . . . meant to awaken in us the sky-like nature of the mind, and to introduce us to that which we really are, our unchanging pure awareness, which underlies the whole of life and death.† (Rinpoche, 2002). Its goal is to relieve the suffering of the mind and lead its practitioners to the enlightenment found by Siddhartha Guatama or the Buddha while he sat beneath the Bodi tree. The mind’s home in meditation is a clear, lucid, unaltered state in which the fragmented frames of thought that usually circulates in the untrained mind are set aside and forced out. A mind free of worry and apprehension is at peace and free of suffering. A number of physical and mental exercises are used to bring the mind to this lucid state of natural existence. The four objects of consideration and awareness when meditating are the body, feelings, state of the mind, and the mind’s contents. Body positioning during meditation has practical and traditional roots. The posture assumed during meditation resembles the crossed leg position of the Buddha. Although there are many variations of posture and hand placement, they all attempt to create and emphasize the connectionShow MoreRelatedMeditation : Meditation And Meditation939 Words   |  4 Pagesdrug or anything like that. What I’m talking about and will be the topic of the article is MEDITATION! If you’re interested in learning more about meditation then this is the article for you. We’ll cover what is meditation, the meditation benefits, and how to begin meditating. What is Meditation? Meditation is control over your state of mind, not something you just do. This state achieved though meditation involves awareness and consciousness. You narrow your mind down to one thing and reduce sporadicRead MoreMeditation : Meditation And Meditation3069 Words   |  13 PagesMindfulness meditation can be very well described as the discipline which has the best of both areas, yoga and meditation. Adopting theses practices in your routine life can not only help you in attaining peace of mind and soul; you can also feel a positive energy surging inside you. They also lead you to a state of self realization, where your mind is away from the anxieties of the past and the anticipations about the future. And when you experience such perfection and balance of the mind and bodyRead MoreMeditation On The Practice Of Meditation1075 Words   |  5 PagesThroughout centuries, meditation has been utilized for spiritual guidance. Meditation is often practiced within quiet rooms, where one cannot be disturbed. In the recent years, meditation has expanded beyond the homes of individuals. Schools across the nation have begun researching t he benefits of meditation on students. The practice of meditation in schools has been shown to promote positive behavior in students; therefore it should be implemented in schools. The practice of meditation can be definedRead MoreA Research Study On Meditation966 Words   |  4 PagesBeatrix Zander 10/15/15 History Research Paper on Meditation May I be well and happy. May I be peaceful and calm. May I be protected from dangers. May my mind be free from hatred. May my heart be filled with love. May I be well and happy. (1) Meditation is a powerful tool that can be used by anyone regardless race,gender,social standing, religion, and intelligence. It’s a unifying practice. Meditation is a conscious effort to change how the mind works for better understanding the world and yourselfRead MoreEssay on Meditation1094 Words   |  5 PagesBack to Presentations Meditation Relaxation lowers blood pressure, calms the nervous system, releases tension in muscles, enhances immune system function, and reverses the damage done by negative stress. For relaxation to work its magic on the body, both the body and mind need to be still, and calm. As left side activity of the brain decreases, the intuitive, creative, right side of the brain becomes more active. We need to quiet the rational side and draw on our inner-wisdom, capacity forRead MoreMeditation : A Long History1237 Words   |  5 PagesMeditation has a long history that stretches back thousands of years. Nobody knows exactly where and when meditation began but scientists have evidence to believe that it began somwehere around 5,000 years ago. This was a time far before religious figures such as Jesus and Buddha are said to have existed. 5,000 years ago, much of the civilized world was nothing like it is today. It was mostly hunter gatherers with few villages in the open landscapes. Meditation is said by scientists to have mostRead MoreThe Meaning of Silence and Meditation 999 Words   |  4 Pagesa number of texts are; meditation, silence, connecting to God and spirituality. Two themes that are fundamental are silence and meditation. In meditation we find silence difficult but this is a factor that we need to work on because it is very important. A hypothesis has been created that will assist in critiquing and evaluating four Spiritual Writings in their attempt to finding the mystery of God. Contemporary Christian spirituality writings suggest that deep meditation and silence are fundamentalRead More Meditation: The Balance of Life Essay997 Words   |  4 Pagesperforming meditation, but recently anyone has been trying it. Meditation is a practice that someone may train their mind to be in a state of consciousness that benefits their mind and body. Meditation is about paying attention, focusing and being very calm. It sharpens creativity and performance while enhancing relati onships. Meditators find when they stop taking things in life so seriously, the self drops away. They are more direct and absorb life easier. (Ellison 36) Meditation has been aroundRead MoreYog Yoga And Meditation753 Words   |  4 Pagesand Meditation The term â€Å"Yoga† has been derived from ye Sanskrit word, â€Å"Yuji† which means union. Through this exercise, a union of the mind and body with a sense of harmony and consciousness is achieved. Yoga is also universal. Yoga is used by many to help with health issues, and an overall feeling of wellness. Even known to help with some cancers. Yoga is not used just for religious purposes. Yoga has been said to have originated in India, before the coming of Christ. Yoga and Meditation areRead MoreReflective Essay On Meditation1711 Words   |  7 PagesMeditation Meditation can be used as a way for stress relief, a form of reflection, or just to spend time with God and speak to him. Most people see meditation as a way to have time to themselves, relax, and think about nature, life, or God. According to Foster, the purpose of meditation is to have focus on faithfulness and obedience for Jesus. A person’s challenge of achieving absolute meditation is overcoming the obstacles of the devil. This means ignoring the distractions around you such as;

Analysis Of David Ogilvy s The Consumer Isn t A Moron

Professional Advertiser - David Ogilvy â€Å"The consumer isn t a moron. She is your wife.† A strongly worded quote from David Ogilvy highlights the importance of the relationship and connection necessary between and advertiser and his or her consumer. Ogilvy, like many others, started from the bottom and worked tirelessly to the top. Born in Oxford, England on June 23, 1911, David would live the next twenty seven years in and around his hometown. David studied at two different colleges and ended up graduating from neither Fettes College nor Christ Church. Going nowhere fast, David began a career working in a kitchen. Not long into his career there did he realize the job description did not match his big ideas for what his life was supposed to be like. David spoke the following words about his kitchen work: â€Å"If I stayed at the Majestic I would have faced years of slave wages, fiendish pressure, and perpetual exhaustion.† Quitting this career opened the door for his big change in the advertising world. (David Ogilvy Biography | Ogilvy Mather) Ogilvy began selling stoves to everyone. Nothing out of the ordinary or overpriced expensive appliances, but a simple generic cooking stove became David’s first encounter with consumers face to face. David took this door to door work very seriously and became one with his clientele. He never limited himself when the sale came down to a consumer. Whether the consumer was a religious service member or a single mother, David spread his

Case Study of Lipids Free Essays

Lipid Panels Case Study Subject #1 This fifty year old man that has no apparent health problems has a low ‘HDL’ of 30mg/dl. That’s not a good thing because he’ll be more likely to develop heart disease or have a heart attack/stroke. Anything over 60mg/dl is considered to be optimal. We will write a custom essay sample on Case Study of Lipids or any similar topic only for you Order Now He is border line high for LDL’s of 160mg/dl, the ideal number is 100mg/dl or lower. That number tells me he is at greater risk to heart disease and/or heart attack. Better diet and exercise would help him tremendously. He is also in the high range for triglycerides at 300mg/dl, considering anything under 150mg/dl is normal. He is at risk for high blood pressure and diabetes to name a couple things. Staying away from cigarettes, eating the right foods, and exercise would be ideal. After 150-199mg/dl it just goes to borderline, then high levels 200-499mg/dl, and then very high levels 500mg/dl or higher. Subject #2 Is a forty five year-old sedentary women who is 5’9† tall and weighs 170 pounds, with a history of hypertension. She has a ‘HDL’ level of 40mg/dl which is not very good it should be at or above 60mg/dl. She has a ‘LDL’ of 140mg/dl that is borderline high and her triglyceride level is at 250mg/dl which is high. She is high risk for heart disease, heart attack, stroke, obesity, and is at risk for metabolic syndrome. These can be greatly reduced by exercising 30 min a day for 4 days, eating healthier foods such as oily fish, fruits, and veggies. Subject #3 Is a sixty year-old sedentary who stands 5’9† tall and his weight is 230lbs. He has an ‘HDL’ level of 25mg/dl and that is low, it should be 60mg/dl or higher. Unfortunately a low (High-Density Lipoprotein) or ‘LDL’ puts you at risk of a heart attack, heart disease, or stroke. Eating less animal and partially hydrogenated fats along with exercise can help. This man has a (Low-Density Lipoprotein) or ‘LDL’ at 250mg/dl which is extremely high. He needs to try and eat more healthy foods like oily fish, veggies, fruits, whole-grains, high-fiber foods, and exercise as much as he can to try and bring that number down. Otherwise he will be more likely to develop heart diseases, stroke or a number of the bad things. And his Triglyceride level was at 115mg/dl, which is pretty good or normal I should say. High triglyceride levels could increase the risk of heart disease and might be a sign of metabolic syndrome. Resources http://circ. ahajournals. org/cgi/content/full/114/1/82 http://americanheart. org/ How to cite Case Study of Lipids, Free Case study samples

Meaning of Ceteris Paribus free essay sample

In economics and finance,  the term is used as shorthand for indicating the effect of one economic variable on another, holding constant all other variables that may affect the second variable One of the disciplines in which ceteris paribus clauses are most widely used is economics, in which they are employed to simplify the formulation and description of economic outcomes. When using ceteris paribus in economics, assume all other variables except those under immediate consideration are held constant, . In effect all extra variables remain unchanged and there are no outside influences on the variables being looked at. The only variables being considered are price and demand. It does not take into account any other things, such as inflation, product improvements, etc. This allows for the explanation, examination and understanding of basic economic rules. This operational description intentionally ignores both known and unknown factors that may also influence the relationship between price and quantity demanded, and thus to assume ceteris paribus is to assume away any interference with the given example. We will write a custom essay sample on Meaning of Ceteris Paribus or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Such factors that would be intentionally ignored include: the relative change in price of substitute goods, (e. g. , the price of beef vs pork or lamb); the level of risk aversion among buyers (e. g. , fear of mad cow disease); and the level of overall demand for a good regardless of its current price level (e. g. a societal shift toward vegetarianism) In this example, the clause is used to operationally describe everything surrounding the relationship between both the price and the quantity demanded of an ordinary good. when  discussing the laws of supply and demand, one could say that  if demand for a given product outweighs supply, ceteris paribus, prices will rise. Here, the use of ceteris paribus is simply saying that as long as all other factors that could affect the outcome (such as  the existence of a substitute product) remain constant, prices will increase in this situation. For example as the price of Pepsi cola rises, the quantity demanded of Pepsi cola falls, ceteris paribus. If the price raise of Pepsi-cola and nothing else changes, in other words, people’s preferences stay the same, the recipe for Pepsi-cola stays the same, and so on, then in response to the higher price of Pepsi-cola, people will buy less Pepsi-cola. In a nutshell the term ceteris paribus is used to define the law of demand and supply and it literally means all other things remain constant and nothing else changes. Meaning of Ceteris Paribus free essay sample In economics and finance,  the term is used as shorthand for indicating the effect of one economic variable on another, holding constant all other variables that may affect the second variable One of the disciplines in which ceteris paribus clauses are most widely used is economics, in which they are employed to simplify the formulation and description of economic outcomes. When using ceteris paribus in economics, assume all other variables except those under immediate consideration are held constant, . In effect all extra variables remain unchanged and there are no outside influences on the variables being looked at. The only variables being considered are price and demand. It does not take into account any other things, such as inflation, product improvements, etc. This allows for the explanation, examination and understanding of basic economic rules. This operational description intentionally ignores both known and unknown factors that may also influence the relationship between price and quantity demanded, and thus to assume ceteris paribus is to assume away any interference with the given example. We will write a custom essay sample on Meaning of Ceteris Paribus or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Such factors that would be intentionally ignored include: the relative change in price of substitute goods, (e. g. , the price of beef vs pork or lamb); the level of risk aversion among buyers (e. g. , fear of mad cow disease); and the level of overall demand for a good regardless of its current price level (e. g. a societal shift toward vegetarianism) In this example, the clause is used to operationally describe everything surrounding the relationship between both the price and the quantity demanded of an ordinary good. when  discussing the laws of supply and demand, one could say that  if demand for a given product outweighs supply, ceteris paribus, prices will rise. Here, the use of ceteris paribus is simply saying that as long as all other factors that could affect the outcome (such as  the existence of a substitute product) remain constant, prices will increase in this situation. For example as the price of Pepsi cola rises, the quantity demanded of Pepsi cola falls, ceteris paribus. If the price raise of Pepsi-cola and nothing else changes, in other words, people’s preferences stay the same, the recipe for Pepsi-cola stays the same, and so on, then in response to the higher price of Pepsi-cola, people will buy less Pepsi-cola. In a nutshell the term ceteris paribus is used to define the law of demand and supply and it literally means all other things remain constant and nothing else changes.

Smart Materials in Aerospace Industry free essay sample

Within each subsection, we will draw a relationship between the properties of the smart material and its molecular mechanism. This is followed by presenting an outline of their recent and future applications, and the experimental procedures and results done in recent researches to show the feasibility of these applications. In the Discussion section, we will be delving into the cost-effectiveness and feasibility of using smart materials in aerospace components. Finally, the conclusion will give an insight into the relationship between the use of smart materials and the design of future aircrafts. 1. Introduction Smart materials are defined as materials that can significantly change their intrinsic properties (mechanical, thermal, optical or electromagnetic), in a predictable and controlled manner in response to their environmental stimulus[1]. In general, these materials can be categorized into 3 categories, namely thermal-to-mechanical (shape memory alloys), electrical-to-mechanical (piezoelectric), and magnetic-to-mechanical (magnetostrictive). Materials engineering has undergone a major transformation in the recent decade, as atoms and molecules are no longer viewed and worked upon on the microscopic level, but now on the nanometer level. We will write a custom essay sample on Smart Materials in Aerospace Industry or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Materials requirements are becoming more complex, especially in the aerospace industry in which safety and cost-effectiveness often conflict against each other. It is no longer acceptable for materials to have a single function; they need to be multifunctional to save costs and weight. Smart materials are now replacing monolithic ones to achieve multiple functions at all scale levels. Hence, smart materials are essentially integrated into the use of aerospace components. What differentiates smart materials from normal monolithic ones? Smart materials exhibit characteristics which most scientists would term as ‘intelligence’. This includes immediacy (the ability to respond in real time); transiency (the ability to respond to more than one environmental states); self-actuation (inherent intelligence within material); selectivity (having a discrete and predictable response); and lastly, directness (response is local to the ‘activating’ event)[2]. The performance characteristics of aircrafts are often limited by properties of materials used in both the airframe and propulsion systems. With the recent advancement of materials technology, high performance materials are created, resulting in a breakthrough in the performance and efficiency of modern aircrafts. The discovery of smart materials provides cost-effective and innovative solutions to the limitations currently faced in the design of aircrafts. These smart materials perform specialized functions when exposed to external stimuli, and they are increasingly being used to replace conventional aircraft parts for better performance. In this report, we shall look at the current and future use of these smart materials in the aerospace industry. 1. Purpose The purpose of this report is to introduce the different types of smart materials and their applications in the aerospace industry. Recent and emerging uses of these smart materials will also be presented, with brief experimental procedures and results obtained from recent researches and experiments to show the feasibility in aerospace applications. 1. 2 Background Smart material transformation was first observed on gold-cadmium, and recorded in 1932. Five year later, in 1938, the same phase transformation was observed in brass. In 1962, Beehler and coworkers discovered the shape memory effects of Nickel-Titanium alloy, and they named this family of alloy as Nitinol. The discovery of Nitinol ignites the discovery of other alloy systems with shape memory effect, and also accelerates the use of smart materials in product development. [3] Since then, aerospace companies are also exploring the use of smart materials in aircraft components. Conventional automatic control systems which use servo-valve or hydraulic actuators face a lot of limitations. These limitations include multiple energy conversions, complexity due to large number of parts resulting in large number of potential failure sites and large weight penalty, high vulnerability of hydraulic network, and frequency limitation. In contrast, the advantages from the use of smart materials actuators include the direct conversion of electrical energy to high frequency linear motion, easier transmission of electrical energy throughout aircraft, and light and compact smart materials induced-strain actuation in place of bulky hydraulic power systems. With this huge potential offered by smart materials, researchers are eager to tap on this potential, by exploring on ways to implement these smart materials into aircraft components. 1. 3 Scope This report will present the 4 common types of smart materials that are popular in the market. A brief description will be made with regards to the mechanism of how the smart materials function. The properties of the smart materials will then be related to their current and future aerospace application. This is followed by the detailed outline of the experimental procedures undertaken by past researches, as well as results obtained which prove the feasibility of using these smart materials for the aerospace applications. Finally, discussions will be made on the viability of the use of smart materials in the aerospace industry, in terms of safety, cost feasibility and future trends. . Types and Applications of Smart Materials 1. Piezoelectric Material Piezoelectricity is the generation of electrical potential in a material in response to a mechanical stress. This is known as the direct effect. It can also mean mechanical deformation upon the application of electrical charge or signal (Harrison JS and Ounaies Z, 2001). In this case, the material can serve as a sensor to detect m echanical stress. In addition, the materials can serve as an actuator when there’s a large increase of size due to electrical stimuli. The two types of piezoelectric materials that are used as smart materials are piezoelectric ceramic and polymer. Properties Piezoelectric materials are widely used as they possess favorable properties such as fast electromechanical response, wide bandwidth, high generative force and relatively low power requirements (Harrison JS and Ounaies Z, 2001). In addition, piezoelectric polymers are flexible, lightweight, and have low acoustic and mechanical impedance, while piezoelectric ceramics are brittle, heavy and toxic. Mechanism Piezoelectric effect is formed in crystals that have no centre of symmetry. One end of the molecule is more negatively charged while the other end is more positively charged, hence a dipole moment exists within the molecule. This is due to both the atomic configuration of the molecule, and also the molecular shape. Polar axis is the imaginary line that runs through the centre of both charges on the molecule. The orientation of the polar axis determines the type of crystal. For monocrystal, all the molecules’ polar axes are oriented in the same direction (Figure 2. 1. 1), while for polycrystal, the polar axes of molecules are oriented in different direction (Figure 2. . 2) [pic][pic] Figure 2. 1. 1 Figure 2. 1. 2 To create the piezoelectric effect, polycrystal is heated under the application of a strong electric field. The high temperature increases the rate of self-diffusion among the molecules, while the strong electric field forces almost all of the dipoles to orient in nearly the same direction (Figure 2. 1. 3) [pic] Figure 2. 1. 3 Piezoelectric ef fect can now be observed in the crystal (Figure 2. 1. 4). Figure (a) shows the piezoelectric material in its neutral state. When the material is compressed, a voltage of the same polarity as the resultant dipole moment will appear between the electrodes (Figure (b)). Conversely, the voltage will be of opposite polarity when the material is expanded (Figure (c)). Similarly, a voltage applied that is opposite to the poling voltage will cause the material to expand(Figure (d)), while an applied voltage of the same polarity will cause the material to be compressed (Figure (e)). If an alternating voltage is applied across the material, the material will vibrate with the same frequency as the signal. [pic] Figure 2. 1. 4 Advantages and Disadvantages[4] Advantages |Disadvantages | |Compact and lightweight |Brittle due to crystalline structure | |Displacement proportional to applied voltage |Produce small strains compared to SMA and magnetostrictives | |Operate over large temperature range |Cannot withstand high shear and tension | |Fast response to applied voltage(msec) |Aging of material | |Repeatable sub-nanom eter steps at high frequency |Uses active control, which can result in instability | |No moving parts |Can become depolarized (at high temperature, high voltages and large | |Function at high frequencies |stresses) | |Excellent stability | | |Easily embedded into laminated composites. Aerospace Applications Piezoelectric materials are mainly used in the aerospace industry for shape control and vibration control. †¢ Tail-Buffet Suppression High performance aircrafts with twin vertical tails often face the aeroelastic phenomenon of tail buffeting, in which the unsteady vortices that emanates from the wing leading edge extensions burst and immerse the vertical tails in their wake. This results in severe vertical tail response and buffet loads, which lowers airframe life and increases maintenance costs. pic][pic] Before the development of piezoelectric actuators, various method of alleviating buffeting was used. One method was the use of hydraulic actuators to superimpose the oscillations of affected control surfaces about their hinges, so as to effect damping. However, this method has two disadvantages. Firstly, the flight control system and buffeting-minimization system must use the same degree of freedom for the same control surface, thus reducing the availabi lity of the control surface for each role. Secondly, operations are limited to low frequencies due to the difficulty of oscillation a large control surface about its hinges. Experiment The Technical Cooperation Program (TTCP) collaborated with National Research Council Canada (NRC) and Department of Defense of Canada (DND) in researching about the feasibility of using piezoelectric actuators for tail buffet suppression on a full-scale F/A-18. The full-scale aircraft was tested in the International Follow-On Structural Test (IFOST) Program rig in Australia (Yousefi-Koma A Zimcik DG 2003). The procedures for the experiment are as follow: †¢ The starboard fin of the aircraft was instrumented with piezoelectric actuators over a wide area on both sides of the fin, as shown in Figure 2. 1. 5. [pic] Figure 2. 1. 5 †¢ Accelerometers and strain gauges are placed strategically to measure displacements, and hence calculate the vibration amplitude. †¢ Electrodynamic shakers are attached to the fin to induce structural vibration. These shakers are controlled by the test rig control system to model actual flight structural loads. †¢ In the experiment, four custom-made high-power amplifiers of 2kVA rating over 200Hz bandwidth were used. Results Conclusion The experimental results have shown that the active control system using piezoelectric actuators was able to effectively suppress the buffet response of the vertical fin at high angle of attack. Amplitude reductions of up to 60% at the normal flight configuration and close to 10% in the worst case scenario were observed (Yousefi-Koma A Zimcik DG 2003). It was estimated even a small 10% reduction in vibration amplitude would double the durability of the fin. Hence, it can be concluded that with the use of piezoelectric actuators in active-control surface modal (ACSM) device to deform the control surface, the control surface not only can respond to buffeting-minimization signals, but also flight control commands. †¢ Wing Flutter Damping When a structure is placed in a flow of sufficiently high velocity, an aeroelastic self-excited vibration takes place, which has a sustained or divergent amplitude. This results in dynamic instability that can get violent. This is because at high speed, the effect of the airstream can cause the coupling of two or more vibration modes such that the vibrating structure will extract energy from the airstream. The extracted energy equals the amount of energy that the structure can dissipate at the critical speed, and a neutrally stable vibration exists. However, above this critical speed, the vibration amplitude will diverge, causing structural failure. Experiment and Result The Piezoelectric Aeroelastic Response Tailoring Investigation was conducted at MIT with the support of NASA, and it aims to achieve the following objectives: determining the power consumption of the piezoelectric actuators while controlling the response of the structure; investigating optimal piezoelectric actuator placement; and, testing disturbance rejection controllers at zero airspeed (Anna-Maria Rivas McGowan). The major components of the 4-feet test model, as shown in Figure 2. 1. , consist of two primary structures: an exterior fiberglass shell, which is used to obtain aerodynamic lift; an interior composite plate that contains the piezoelectric actuators, and is made up of an aluminium honeycomb core sandwiche d by graphite epoxy plates. The plates are of [20 °2/0 °]s laminate, referenced to the wings quarter-chord which is swept 30 °, and this provides a static coupling of the bending and torsional behaviour. Fifteen groups of piezoceramic actuators patches are placed at the top and bottom of the interior plate, and they are configured to impart moments to the plate. Together with the orientation of the graphite epoxy and the wing sweep angle, the actuators can affect bending and torsional vibration of the model. Forces on the model were monitored using ten strain gauges and four accelerometers. To acquire time history data, each of the 15 piezoelectric actuator groups was activated individually, as well as in five sets of several actuator groups. The experimental results is shown in the graphs in Figure 2. 1. 7. In summary, it shows that the control system can effect successful flutter suppression and gust reduction in the model, with a 12% increase in flutter damping and 75% decrease in root-bending moment caused by gusts. This clearly shows the potential of the use of piezoelectric actuators in suppressing the detrimental effects of wing flutter. Rotor Blade Twist Outboard portion of the blade travel faster, and with the same lift coefficient, higher lift force is concentrated near the blade tip. To distribute the lift force evenly among the blades, the angle of attack is made to be lower near the blade tip, and higher near the blade root, such that the lift coefficient decreases with increasing distance from the blade root. This can be done by induced blade twisting, through the embedment of piezoelectric materials into the blade skin. Active fibre composites (AFC) are actually used, which consists of continuous, aligned PZT fibres in an epoxy layer (Figure 2. 1. ), and copper electrode films that are etched into an inter-digitated pattern to effect the electric field along the fibre direction, as shown in Figure 2. 1. 9 (Rodgers and Hagood, 1998). [pic][pic] Figure 2. 1. 8 Figure 2. 1. 9 Experiment Active Fiber Composite (AFC) was fitted into the construction of a 1/6th scale replicate of CH-47D blade model (60. 619in span and 5. 388in chord). The blade was sent for wind tunnel testing at Boeing Helicopters, PA. Three AFC plies were diagonally placed in the co-cured D-spar blade lay-up. When the fibres are activated, it causes a shear in the spar skin, which creates the blade twist effect.