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The Westerner vs “The Bride Comes to Yellow Sky”

Claire Schneider Joseph Libis English 1002 May 30, 2009 Two works of Literature, â€Å"The Bride Comes to Yellow Sky†, the short story, and â€Å"The Westerner†, the film, attempt to pass on the human advancement of the old west, which takes into account settlement and improvement of conventional American qualities, which are related with fair and dedicated individuals in the West Texas outskirts. Albeit, one of these works makes a superior showing of passing on in general theme.Between â€Å"The Bride comes to Yellow Sky† and â€Å"The Westerner†, I would state that â€Å"The Westerner made a superior showing of acculturating on the Western wilderness. All through the film, it appeared as they were continually contending with one another, however at long last Jane Ellen Mathews, and Carl Hardin became companions. One approach to demonstrate this would be that Carl had said that he thought Jane Ellen’s hair was the most delightful hair he had ever observed. He needed to keep a lock of her hair.To me, that says a great deal on the off chance that you need to keep a lock of approximately ones hair. There was a scene in which there was a play in which Judge Roy Bean bought the entirety of the tickets for. Before the play started, Carl Hardin showed up, and they began to have a shooting match. I’m not certain what the explanation was. After a long match, the two of them chose to call it even and make up. It’s constantly incredible when motion pictures end up having an extraordinary closure. Two of the characters, Jane Ellen, and Carl Hardin, needed to have a home together.In Bride Comes to Yellow Sky, two individuals have quite recently gotten hitched, and are ready a train to Yellow Sky. At the point when they show up back in Yellow Sky, they surge towards Jack Potter’s house, however they see, on their way six men sitting at a bar, and a man comes out and reports that Scratchy Wilson has been drinking once more. In the earliest reference point of â€Å"The Westerner† there were men sitting at a bar drinking. This would be one similitude that the two works of writing share.

The Effect of Hormones on Your Social Anxiety

The Effect of Hormones on Your Social Anxiety Social Anxiety Disorder Diagnosis Print How Hormones Play a Role in Social Anxiety By Arlin Cuncic Arlin Cuncic, MA, is the author of Therapy in Focus: What to Expect from CBT for Social Anxiety Disorder and 7 Weeks to Reduce Anxiety. Learn about our editorial policy Arlin Cuncic Medically reviewed by Medically reviewed by Steven Gans, MD on February 28, 2017 Steven Gans, MD is board-certified in psychiatry and is an active supervisor, teacher, and mentor at Massachusetts General Hospital. Learn about our Medical Review Board Steven Gans, MD Updated on September 19, 2019 Social Anxiety Disorder Overview Symptoms & Diagnosis Causes Treatment Living With In Children martin-dm / Getty Images In This Article Table of Contents Expand Increased Anxiety Reduced Anxiety Managing Hormones Hormone Therapy View All Did you know that that hormones and anxiety are related in certain ways, such that your hormones may have a relation to how anxious you feel? When hormone levels are too high or too low, this can influence neurotransmitters, resulting in problems such as increased anxiety. People who live with social anxiety disorder (SAD) may find that levels of certain hormones related to feelings of increased or decreased social anxiety. Hormones That May  Increase  Social Anxiety There are three categories of hormones that may influence your social anxiety: stress hormones, sex hormones, and thyroid hormones. Learning more about how these hormones affect your body and mind is the first step to managing the impact of hormones on your anxiety levels. Stress Hormones (Adrenaline, Cortisol) Stress hormones are  released in situations where you feel out of control, overwhelmed, or severe anxiety (such as during the fight-or-flight response), which can increase your social anxiety. When you experience a stressful social or performance situation, your body responds by releasing hormones like adrenaline and cortisol to help you cope with the threat and prepare you for action. However, in the face of no actual physical threat, excess levels of these hormones leave you feeling anxious, to the point that you may experience a panic attack or the feeling of needing to escape. This becomes a vicious cycle: your hormones cause anxiety, the anxiety causes more hormones to be released, and so on. Sex Hormones (Testosterone, Estrogen) Sex hormones may also play a role in how much anxiety you experience. Changing levels of the sex hormones estrogen and testosterone can affect your social anxiety. Too little testosterone has been linked with increased anxiety, while female sex hormones such as estrogen may also be linked to anxiety symptoms. This is why anxiety often peaks during times of hormonal change such as during puberty, at certain times of the menstrual cycle in women, and during menopause in women. Stress and sex hormones can also have a combined  effect on anxiety. For example, when you experience stress, cortisol increases, which slows your bodys ability to make testosterone. The combined effect of increased cortisol and lowered testosterone means you feel more anxious. If that isnt bad enough, testosterone has partial control of the release of cortisol, so when testosterone is lowered, cortisol is more likely to increase. You can see why anxiety is a cycle that feeds itselfâ€"and that breaking this cycle is key to overcoming your symptoms. Thyroid Hormones Finally, there is a third type of hormone that may influence your anxiety: thyroid hormones. An overactive thyroid can create anxiety in the form of physical symptoms such as increased heart rate, palpitations, shakiness, and increased sweating. If you live with a thyroid condition, this may make your social anxiety worse. Hormones That May Reduce Social Anxiety If you think hormones are all badâ€"think again! There are actually some ways in which certain levels of hormones can help to reduce your anxiety. Testosterone Just as too little testosterone may increase social anxiety, increased testosterone may help to reduce it. Administration of testosterone, a steroid hormone,  has been shown to reduce socially fearful, avoidant, and submissive behavior. Indeed, in general, men have half the reported rate of anxiety disorders as women; this may be partially due to the role of testosterone in levels of anxiety. Testosterone boosts the action of gamma aminobutyric acid (GABA) and serotonin. These two brain chemicals are related to social anxiety disorder. Testosterone also reduces the activity of the amygdala, which is the brain structure related to fear and that initiates the fight-or-flight reaction. Increased testosterone means you are working with an amygdala that responds more like a person without an anxiety disorder. Estrogen Estrogen is known to calm the fear response in women. Specifically, research has shown that women trained on a fear-extinction task do better when the level of estrogen in their blood is higher. As a female, you may have also noticed that your ability to feel calm and relaxed (versus anxious and afraid) is better at certain points during your menstrual cycle. Oxytocin Youve probably heard of the love or bonding hormone, oxytocin. This is a peptide hormone, which acts as both a hormone and a brain neurotransmitter. It is known as the love hormone because it is released during contact with a loved one. Oxytocin is made in the hypothalamus and transported and secreted by the pituitary gland at the base of the brain. Its release also helps with childbirth and breastfeeding. In terms of its relation to mental health, oxytocin is known to have an anti-anxiety effect and may help to relieve social anxiety. Research shows that oxytocin promotes relaxation, trust, and stability, all of which make it easier to manage social situations. In fact, studies are ongoing on the role of oxytocin and how it could be used in the treatment of social impairments (including the social implications of autism). Vasopressin Finally, vasopressin is a hormone that regulates the bodys fluid balance. In addition, it is involved in the regulation of anxiety, stress coping, and social behavior. Vasopressin is released within the hypothalamus and limbic areas of the brain. Some researchers think that a balance must be struck between oxytocin and vasopressin for optimal social functioning. Vasopressin is particularly related to social behavior, sexual motivation, pair bonding, and maternal responses to stress. Steps to Managing Hormones and Relieving Social Anxiety Although hormonal changes may be related to social anxiety, treatment with hormonal therapy is not currently a common recommendation. Instead, your best option is some form of traditional treatment for SAD (e.g., medication or therapy) as well as understanding and adapting to the role of hormones in your anxiety. What is not helpful is self-medicating. Try to avoid temporary fixes like sugar, alcohol, smoking cigarettes,  or other substances that give you a quick feel-good surge but dont solve the long-term anxiety problem. Below are six tips to get you started: 1. You can increase your levels of testosterone and oxytocin naturally! These are things that are easy to do, but that you have to make a commitment to following through with. Increase testosterone by doing the following: Getting regular exerciseEating a balanced dietMinimizing stress (and therefore testosterone-depleting cortisol)Taking a multivitaminGet enough sleep each night Increase oxytocin by doing the following: Cuddling with a loved oneListening carefully when others speakBeing generous toward others (giving gifts)Trying metta meditation, which involves meditation designed to inspire love and kindness toward othersGoing on social mediaPetting a dog or cat 2. Use cognitive-behavioral therapy (CBT) techniques to learn new patterns of responding to anxiety. Over time, neural pathways in your brain will change, which will help to reduce your anxious responses to stressful situations. 3. If you have a thyroid condition that may be affecting your anxiety level, ask your doctor whether the two could be related and how treating your thyroid condition may help. 4. If you are female, learn how variations in hormones over your life and during the course of a month may influence anxious feelings. Just knowing how hormones may be affecting you may help you to stop and think: This situation is not causing my anxiety; my body is reacting to change in hormones,  which may allow you to take a step back and accept your feelings for what they are. 5. Research shows that adopting a strong pose (such as the Wonder Woman pose, with feet hip-width apart and hands on hips) for a few minutes may lead to increased testosterone and feelings of confidence, which in turn will help to lower social anxiety. 6. Take natural supplements that may help to lower stress levels (and cortisol) such as  ashwagandha. Note, however, that these type of supplements are not regulated by the Food and Drug Administration (FDA) and have not been tested by this regulatory body for safety and efficacy. Is Hormone Therapy for Social Anxiety Possible? While it may sound fanciful that one day we might treat anxiety disorders with hormone therapy, the truth is that research on this topic is already happening. In one study, it was shown that women exposed to trauma who were administered female sex hormones (in the form of the morning-after pill, after a sexual assault) were less likely to develop post-traumatic stress disorder (PTSD) after the event. This fascinating and ground-breaking research is likely to lead to advances in the area of hormone treatment of anxiety. It isnt that much of a stretch to imagine that this new understanding of the role of hormones in anxiety and fear could lead to treatments that relate to hormones. At present, however, beyond treating an underlying thyroid condition, or hormone replacement therapy (HRT) for problems related to menopause in women, your doctor is not likely to prescribe hormone treatment that will help to improve social anxiety. A Word From Verywell The best approach to managing social anxiety in light of the influence of your hormones is to understand natural fluctuations and  learn ways to boost hormones that help to reduce anxiety. However, if severe social anxiety is a problem for you and you have not sought diagnosis or treatment, its best to visit your family doctor for a referral to a mental health specialist. Effective treatments such as medication and CBT can be helpful in managing SAD that has gotten out of control. Rememberâ€"your anxiety does not define you and is not who you are. You can move past it with the right help. While hormones may be involved, you are not destined to live with social anxiety for the rest of your life. The 7 Best Online Anxiety Support Groups

Opportunities in the Wine Industry in China Free Essay Example, 1500 words

China has invested in research and development. In this regard, China has strengthened its science and education program through the integration of technology in technical colleges and universities. Fifth, the human capital development program will ensure equal education opportunities for elementary education (in primary learning institutions) through the reduction of the cost of school fees in less developed areas. Sixth, the Chinese government is improving its participatory role in market development through modernization of rural agricultural industries, reforming the regional administrative system and the provision of public goods (Wong and Wei, 2007). Adequate planning and integration of the plans and efficiency of implementation, China has dominated the East Asian economy. Chinese exports to other states have experienced a 15 percent increase, thereby ranking Chine the largest exporter of merchandise goods to Eastern Asia and the fourth largest exporter of the same products gl obally. China has taken advantage of its large size, the similarity of culture, the abundance of resources, liberalization of trade and low-technology capital intensive production technique to displace its competitors within the East Asian region. China s economic growth has resulted in the importation of high priced products from technologically advanced East Asian neighbors, the quantity of these imports has reduced significantly compared to its exports. We will write a custom essay sample on Opportunities in the Wine Industry in China or any topic specifically for you Only $17.96 $11.86/page

It s Come A Long Way From The First Draft - 1477 Words

This is the final draft of the essay. It’s come a long way from the first draft. The details are present and the thread is more clear. At least to me, the writer, it is. I’m proud of the elements I’ve chosen and of the way I’ve chosen to connect them. The use of freedom as a thread was difficult, yet the perfect challenge I needed. I love my thread, yet I’m not super confident in my imagery within the piece. I tried to incorporate more sensual imagery, but only accomplished visual imagery, a little bit of touch and smell. I’m proud of this piece merely because I managed to connect two things I absolutely love (nature and equine) with an issue we still face in this world, acceptance of others, ourselves and racism. Racism was displayed in the freedom taking of another man. Never did I think I would be able to connect these 4 completely different ideas in such a simple, yet complex way and absolutely love it. I’ve never been more excited about of a piece of writing and allowing people to read it than I am with this piece. There are so many things I’m proud of with this writing, but there are a few things I feel I’m weak in. I’m not quite sure everyone will agree with my thread being present throughout my entire essay, although I think it is, but maybe that’s because I wrote. I’m not quite sure if the repetition of the words ‘free’ and ‘freedom’ were effective or really necessary. And the imagery as I already said. I’m lacking the sense of taste as how do I represent taste withShow MoreRelatedI Am A Great Deal Of Anxiety Essay1145 Words   |  5 Pagesafter reading the three articles Donald M. 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There is no equivalent ceremony for girls; however, recently some young Jewish couples have celebrated the birth of a daughter. Despite this, females are viewed by most as temporary residents who will eventually become a part of her husband s family. These practices are very discr iminatoryRead MoreWhy I Would Love : Mavs Moneyball?856 Words   |  4 Pagesa multitude of reasons why I would love to contribute to the site. Firstly, I ve been an avid reader for the better part of two years. I love the site and it s my go to place for all things Mavs, which is becoming harder and harder to find these days. Secondly, and more importantly, I absolutely love the NBA and the Mavs. My first true memory of the Mavs was Game 3 of the 2003 Western Conference Semi-Finals vs. the Kings. As I m sure you know, the Mavs were in what appeared to be an absolute

Dont get me started on… Valentine s Day Free Essays

Valentine’ s Day is trying to abduct me into a fake world where everything is glorious and perfect, a world we all wish to be living in. February 14th is the date I most dread every year. Couples get loved up and forget about the important things in life, such as working nine to five to pay the enormous bills that are piled in a drawer or scattered in the living room. We will write a custom essay sample on Dont get me started on†¦ Valentine s Day or any similar topic only for you Order Now Using Valentine’s Day as a runaway from bills isn’t going to make things better. Running away from Valentine’s Day sounds more appealing, it stop’s us from meeting women like these: 1) The hopefuls: These are women who get excited on Valentine’s Day because they believe their special person is out there somewhere, and loneliness isn’t an option. 2) The women who know love only exists in fairytales. These women would sit alone watching a romantic movie. They would cry, curled up on the sofa, every time there’s a romantic scene, while their full mug of hot chocolate gently warms the palms of their hands. Valentines Day is an excuse to advertise couples kissing and holding hands in public. Why would you want to advertise kissing? Which leads to interaction, which surely leads to†¦ yeah, you get my point? It’s not the best example for kids now-a-days is it? Wherever you go, even at the local shop, you’re reminded of this day with hearts, cupids and silly poems on the front of handmade cards. Believe it or not, I caught the bus and I went to town for a small portion of chips with sausage in batter, My FAVOURITE. And on the standing notice board, written in red chalk was: VALENTINES DAY OFFER, small portion of chips and sausage in batter,  £2.99 only. What a massive bargain. I’d never thought I’d hate to love the meal I always devour, little did I know.  £2.99 was a bargain, but I turned away and went in the nearby corner shop, to pick up some cheese and onion crisps instead. At least I could enjoy eating without the reminder of Valentine’s Day on my back. We all know when it’s coming, we’re not stupid. Living close to cinemas, restaurants, shopping centres, bowling alleys and night-clubs could be perceived to be an incredible place to live; everything is close by (except the chip shop). I guess it’s convenient as I’m quite out going, but it is the worse place to live on February 14th. Why? Because the whole area is full of teenagers drunk with fatigue, and middle-aged couples walking tall and ecstatic as if they are The bee’s knees. The only people with class on this irritating day are old people, they are respectful and they don’t go out with the hundred-and -something year old partner. They keep to themselves, like everyone should. Right? People that go out on Valentine’s Day are not paying attention to others feelings, now how selfish is that? Husbands and wives become immediately closer in 24 hours however, after 24 hours it was like they never were. Love is unconditional and is â€Å"life-long† if you love the person. But Valentine’s Day only lasts 24 hours. So, what about the other 364 days? We don’t have love your pet day, because you’re supposed to do that anyway. New years and Christmas are two good reasons for going out and celebrating. A new year is a day where we all are overwhelmed for the year to coming, while Christmas is celebrating Jesus’ birthday. And then there’s Valentine’s Day†¦ An interesting way for the government to continue making a ridiculous amount of money – which would probably be spent on single parents benefits. This makes me think. Government= a greedy bunch of people who needs money to operate. So that’s it. Valentine’s Day is just a day the government make money, they don’t care about lovers. People are not thinking outside the box and why there really is a valentine’s day, it’s all a part of the government’s evil and sick plan. How to cite Dont get me started on†¦ Valentine s Day, Papers

Marzouq Alsaid Essays (400 words) - , Term Papers

Marzouq Alsaid Professor: Andrea Harris ENG 2100 Writing process Assignment 5 10 December 2016 Taking in consideration the three main elements of persuasive speech, which are pathos, logos, and ethos and implementing them in my presentation, will make a huge impact on the effectiveness of my presentation. For example, in the beginning using a personal story as introduction, beside the fact that it grabs the audience attention, it is also a double-edged sword that can approach the audience into pathos and logos appeal. For example, by telling the personal story that happen to one of my closest friend, who was with me in high school, a friend who I used to hangout a lot with him, a person who I spent many wonderful moments with and suddenly I saw him in the hospital with one kidney, demonstrating to the audience how harsh that was for me to see, and also relate to them by saying how many of you ladies and gentlemen wouldn't like to see his closest friend or family member in this situation? This will waken the emotional feelings of the audience and let them interact with my pr esentation in emotional way. On the other hand, telling this story and emphasizing the point that Abdullhadi was my closest friend who I spent a lot of time with even after his kidney lost that illustrate to the audience the fact that I am person who have knowledge about this issue and I know how it feels (Logos). In addition, using statistics to support my main points or my proposed action, can increase the logical aspect of my argument, and make it sounds more credible. When I dressed up well for my presentation I was aiming to hit the ethos appeal. For instance, dressing up nice and look professional will send a message to the audience that I am a gentleman who knows what he is doing or talking about, which will make me look more credible than a person who doesn't dress up well, because he shows that he doesn't care about looking formal when giving a formal serious issue, so people will not pay attention to him. All these factors that I have stated above will have a significant role in helping me to persuade the audience and make sure to hit all the three different appeals of persuaion in my presentation.

MEM Case Study Questions (Harvard Business School)

MEM Case Study Questions (Harvard Business School) INTRODUCTIONMEM Company, Inc., started up in 1883 by Mark Edward Mayer, produces an extensive range of colognes and toiletries. Sales had decreased over the year and MEM is now looking into several options to improve growth. After much extensive analysis, our team had decided to drop the option of launching Cambridge due to the stiff competition from Shulton's Blue Stratos which has a $12 million marketing budget with a fresh slogan, 'Unleash the Spirit', which we believe will differentiate Blue Stratos from the competition. Without the financial muscle and distinct product differentiation, Cambridge would languish in the shadow of Blue Stratos. Therefore, our team suggests that MEM should concentrate on repositioning itself in the market to retain and attract customers.PRODUCTBased on the data given, we found out that there are multiple products that are targeted at the same group of consumers. We found that this problem might have been caused by the process in choosing fragrance fr om the manufacturer.Mem à » Zà ®nIt is stated that most of the time, the research results turn out to be inconclusive. We feel that it is important to have a wider test market that does not belong to the employees of the company and that a clear guideline is given to them to ensure that they know what is the process about.Another suggestion we have is to remove Lime from the product line as it targets at the same consumers as Musk. Furthermore, Lime only makes up for a 2.3% of total sales and most of it is from the sale of the gift sets. By eliminating Lime, there will be more shelf space freed to display other products. The withdraw production of product Lime will provide more cash available for advertising budget. Production efficiency can also be improved. It is...

Homeschooling with Dysgraphia

Homeschooling with Dysgraphia Parents of children with special needs often worry that theyre not qualified to homeschool. They feel that they dont have the knowledge or skill to meet their childs needs. However,  the ability to offer a one-on-one learning environment along with practical accommodations and modifications often makes homeschooling the ideal situation for special needs children.  Ã‚  Dyslexia,  dysgraphia, and dyscalculia are three learning challenges that may be well-suited for a homeschool learning environment. Ive invited Shawna Wingert to discuss the challenges and benefits of homeschooling students with dysgraphia, a learning challenge that impacts a persons ability to write. Shawna writes about motherhood, special needs, and the beauty of everyday messes at Not the Former Things. She is also the author of two books, Everyday Autism and Special Education at Home. What unique challenges do students with dysgraphia and dyslexia face? My oldest son is 13 years old. He started reading when he was only three years old. He is currently taking college-level courses and is quite academically advanced,  yet he struggles to write his full name. My youngest son is 10 years old. He cannot read above a first-grade level and has a dyslexia diagnosis. He participates in many of his older brother’s courses, as long as they are verbal lessons. He is incredibly bright. He, too, struggles to write his full name. Dysgraphia is a learning difference that affects both of my children, not just in their ability to write, but often in their experiences interacting in the world. Dysgraphia is a condition that makes written expression extremely challenging  for children. It is considered a processing disorder – meaning that the brain has trouble with one or more of the steps, and/or the sequencing of the steps, involved in writing a thought down on paper. For example, in order for my oldest son to write, he must first bear the sensory experience of holding a pencil appropriately. After several years and various therapies, he still struggles with this most fundamental aspect of writing. For my youngest, he has to think about what to communicate, and then break that down into words and letters. Both of these tasks take much longer for children with challenges such as dysgraphia and dyslexia than for an average child. Because each step in the writing process takes longer, a child with dysgraphia inevitably struggles to keep up with his peers - and at times, even his own thoughts - as he laboriously puts pen to paper. Even the most basic sentence requires an inordinate amount of thought, patience, and time to write. How and why does  dysgraphia  affect writing? There are many reasons that a child may struggle with effective written communication, including​​: Graphomotor processing  Ã¢â‚¬â€œ trouble with the fine motor coordination required to manipulate a writing instrumentAttention disorders  Ã¢â‚¬â€œ difficulty planning and seeing writing tasks through to completionSpatial ordering  Ã¢â‚¬â€œ challenges in organizing letters and words on the written pageSequential ordering – difficulty in determining the logical order of letters, words, and/or ideasWorking memory – trouble recalling and holding onto the information the writer is trying to communicateLanguage processing – difficulty in using and comprehending language in any format In addition, dysgraphia often occurs in conjunction with other learning differences including dyslexia, ADD/ADHD, and autism spectrum disorder. In our case, it is a combination of several of these difficulties than affect my sons’ written expression. I am often asked, â€Å"How do you know it’s dysgraphia and not just laziness or a lack of motivation?† (Incidentally, I am often asked this type of question about all of my sons’ learning differences, not just dysgraphia.) My answer is usually something like, â€Å"My son has been practicing writing his name since he was four years old. He is thirteen now, and he still wrote it incorrectly when he signed his friend’s cast yesterday. That’s how I know. Well, that and the hours of evaluations he underwent to determine a diagnosis.† What are some of the signs of dysgraphia? Dysgraphia can be difficult to identify in the early elementary school years. It becomes increasingly apparent over time. The most common signs of dysgraphia include: Messy handwriting that is difficult to read  Slow and laborious writing  paceInappropriate spacing of letters and wordsTrouble gripping a writing instrument or maintaining grip over timeDifficulty organizing information when writing These signs can be difficult to assess. For example, my youngest son has great handwriting, but only because he painstakingly works to print every single letter. When he was younger, he would look at the handwriting chart and mirror the letters exactly. He is a natural artist so he works very hard to make sure his writing â€Å"looks nice†. Because of that effort, it can take him much longer to write a sentence than most children his age. Dysgraphia causes understandable frustration. In our experience, it has also caused some social issues, as my sons often feel inadequate with other children. Even something like signing a birthday card causes significant stress. What are some of the strategies for dealing with dysgraphia? As we have become more aware of what dysgraphia is, and how it affects my sons, we have found some effective strategies that help minimize its effects.   Writing in other mediums – Often, my sons are better able to practice the art of written expression when using something other than a pencil. When they were younger, it meant practicing spelling words by writing them in shaving cream on the shower wall. As they grew, they both graduated to using Sharpie markers (making grip much easier) and then finally onto other implements.Allowing larger text – My sons write much larger  than the lines on the college ruled paper in their notepads. Often, they write even larger than the wide ruled paper in their elementary notepads. Allowing larger text size enables them to focus on the sequencing and motor skills associated with writing. Over time, as they have become more comfortable, their written text has become smaller.Occupational therapy – A good occupational therapist knows how to help with pencil grip and the fine motor skills required for writing. We have had success with OT, and I would highly recommend occupationa l therapy as a starting point. Accommodations – Speech-to-text applications and programs, offering additional time for written testing, allowing keyboarding for taking notes, and taking frequent breaks are all accommodations we employ to help my children write more effectively. New technologies have become an invaluable resource for my children, and I am grateful we live in a time where they have access to these types of accommodations. ThoughtCos Eileen Bailey also suggests: Using paper with raised linesBreaking writing assignments into smaller tasksNot penalizing students for spelling or neatness on timed writing assignmentsLooking for fun writing activities   source Dysgraphia is a part of my sons’ lives. It is a constant concern for them, not only in their education, but in their interactions with the world. In order to eliminate any misunderstandings, my children are aware of their dysgraphia diagnoses. They are prepared to explain what it means and ask for help. Unfortunately, all too often there is an assumption that they are lazy and unmotivated, avoiding unwanted work. It is my hope that as more people  learn what dysgraphia is, and more importantly, what it means for those it affects, this will change. In the meantime, I am encouraged that we have found so many ways to help our children learn to write well, and communicate effectively.

Comic Books in America and Japan Case Study Example | Topics and Well Written Essays - 2750 words

Comic Books in America and Japan - Case Study Example The most vital demographic within the society are the children and youth. These active societal members have a greater impact towards future development. However, children are the most sensitive group within the society because they are at the developmental stage that is affected through influences from the majority of the aspects within the society. Moreover, the age is the most active in leisure activities because they require the socialization aspects that develop their intellectuality. The development and the children have been dependent on the presented values within the family and the environment that they hail from. Various societies present differentiated challenges to create a tradition f the nature these children relate to the accorded aspects. The group relations and the activities that these children engage in during their leisure time have influence their developmental attributes (Turow 2008, p159). Most children are involved in games that are both presented in technolog ical aspects and creative social groups. The most applied measures have been in comic books that have witnessed increased use in children. Comic books are either locally created or imported and often follow a similar fictional plot that children have associated with and identified easily (Gravett 2004, p13). Comic books have been boosted by technology as the children have accessed comic plots through the internet in computers and mobile phone. Both America and Japan have witnessed the increased trend of comic books use in children, and the regions depict a variation in behaviour as the entity presents impacts to their development. Japanese manga and American Comics Overview These two countries have been presented with similarities and exchange of intellectual development since the Second World War. The comic book prevalence in the two countries has been evident in the inclusion of super heroes in the fictional writings. The term has always been the comic book in America and the incl usion of manga in Japan. The argument is placed that the creation of the American comic books and super heroes influenced the creation of the manga characters. This fictional society has offered entertainment to an increasing audience, that has been noticed to incorporate children who are influenced in the fictional society in varied measures. The comparison in the traditional definition of both comics and manga are included in their significance to the publication industry. Comics had been developed in the American societies, in the thirties, when the superhero aspect gained popularity. They have since affected the creation of the Japanese manga that have borrowed on the ideology of creation based on the intuition of stars like Batman and Superman. Japanese production of the manga has been larger as compared to the American comic industry occupying a total of 40% in the total publication production. This is because the composition of the manga contents has been dynamic and to cover an increased scope as compared to the comics. The interest has increased among the users who have incorporated the application of the Japanese comic in their entertainment. Consequently, comic books plot has been developed to increase the creativity and involvement of the youth and children as compared to the manga that are a universal story influence. The argument has been placed that the Japanese manga have presented greater influences as compared to the

Individual Projct Essay Example | Topics and Well Written Essays - 750 words

Individual Projct - Essay Example Style of management which needs to be applied to a particular organization depends upon various facts. The style of management should be selected according to the nature and size of the organization. The respective style of management should be able to solve all the problems faced by the organization and it should positively contribute for the overall growth and prosperity of the organization. Style of management selected for an organization should be able to handle all the departments, infrastructure and human resource of the organization. The appropriate style of management can increase the efficiency and performance of an organization to a good extent. ‘The right to strike’ is the most basic aspect of any style of management. The level to which the employees are able to strike and the extent to which they are capable of doing so are crucial factors as far as the success of the organization is concerned. The organization will be successful only if the work is coordinat ed and organized properly and if all the staff shows a cooperative mood. The work flow as well as the commitment of the employees depends upon the style of management that is implemented in that organization. Different organizations choose different styles of management. Scientific management is opted by certain organizations as their management strategy. Some other organizations go for human relations management. Scientific management is a particular type of approach to management and industrial organizational psychology. Scientific management is applicable in large manufacturing factories having complex production methods. This style of management talks about the advantages of division of labor. According to the theories of scientific management jobs should be assigned to people depending upon their talents and capabilities. It should be categorized and divided among the respective suitable staff. Scientific management explains the necessity of allocating

Major League Baseball Salaries and the Economic Effect Competition and

Major League Baseball Salaries and the Economic Effect Competition and the Consumer As long has there has been business, Management and Labor have warred against each other for a bigger piece of the pie. Major League Baseball is no different. In the early years of professional baseball the owners controlled the salaries of the players and decided where they could play and what they would be paid. The players were bound to their team by the Reserve Clause that stated, the services of a player will be reserved exclusively for that team for the next season. This resulted in keeping the player’s salaries artificially low because the players were not allowed to offer their services to any other team. The Reserve Clause was in effect for more than One Hundred years of baseball history. It was challenged several times but the owners had won every time, until in 1970 when the St. Louis Cardinals traded outfielder Curt Flood to the Philadelphia Phillies. Flood refused to play for the Phillies and sued to become a free-agent. Flood’s case was in court for severa l years going all the way to the Supreme Court. He was never able to play in the Major League again. While he did not win his case, he laid the groundwork for a later case that involved two pitchers, Andy Messersmith and Dave McNally who filed a grievance against the league contending that, because they didn't sign contracts with their previous teams they were free agents. The owners and the Players Association agreed to submit to binding, impartial, arbitration in order to settle this case. On December 23, 1975 the arbitrator Peter Seitz ruled in favor of the players and the Reserve Clause was broken, and the era of free agency began in the Major Leagues. In 1976 when free agency began the average player salary was only $52 thousand dollars, but it has increased steadily ever since. By 1990 the average salary for a Major League Baseball player had risen to $589 thousand dollars. This Year baseball will start the 2001 season with an average player salary of more than $2 million, abo ut 40 times higher than the typical wage in 1976 when free agency began. Average Major League Player Salaries 1976-2000 Year Average Increase/decrease Median1976 $52,300 --- *1977 74,000 41.49% ... ... _ap/ 19. 2000 Major League Baseball Salaries: USA Today. May 1, 2000. Arlington, VA. 20. 1999-2000 Major League Baseball Team and Player Salaries: About.com. Aug 31, 2000. Chicago, IL. http://sportsbusiness.about.com/sports/sportsbusiness/library/salary/mlb/9900/ bl_teams_9900.htm 21. Final 2000 Payroll Figures: CNNSI.com. Nov 21, 2000. Atlanta, GA. http://sportsillustrated.cnn.com/baseball/mlb/news/2000/11/21/2000_payrolls/ 22. History of Highest Paid Players: ESPN.com. Jan 15, 1999. Bristol, CT. http://espn.go.com/mlb/s/mlbsalary.html 23. Highest Salaries: CNNSI.com. Dec 11, 2000. Atlanta, GA. http://sportsillustrated.cnn.com/baseball/mlb/news/2001/10/20/highest_salaries _ap/ 24. Franchise Values: The Hartford Courant. May 29, 2000. Hartford, CT. 25. 2000 MLB Team Payrolls: About.com. Aug 31, 2000. Chicago, IL.http://baseball.about.com/sports/baseball/library/weekly/blteamsalaries.htm 26. MLB Player Extend Collective Bargaining Agreement: About.com. Aug 29, 2000. Chicago IL. http://sportsbusiness.about.com/sports/sportsbusiness/library/n†¦/bl082900news.htm

Benefits of Studying Psychology Essay

Question / Topic: Some critics argue that there is no such thing as a psychologically whole person because everyone is fundamentally flawed. Hence, there should not be a need for learning Psychology in this world. What is your response to this? Introduction: What is psychology? The word ‘psyche’ means breath,spirit,soul and logia means study of. It is a scientific study of behavior and mental process. Psychology is all around us like the way people behave, talk and do things. It is an interesting field to learn and it helps in crafting us into a whole person. Thus, the communication skill with them is increased also. †¢A good example for this will be in the education field, where a teacher who needs to deal with children will benefit by learning how to engage in an interesting way of teaching to attract the attention of his/her students. Concluding Sentence: Therefore, we see clearly that a better understanding of human mind and thought process helps to add quality and depth to our relationships with people around us. Topic sentence : Apart from that, learning psychology creates stronger conflict and problem solving capability in a person. Most people tend to lose their mind and become nervous, emotional and unable to decide when a problem arises. This can be avoided by a person who learns psychology. †¢When a problem comes up, a person who has learned psychology can take time to evaluate the situation, evaluating every option available and not to rush thru decision. In other words, he can be logical and not emotionally driven t o make a decision. †¢Addition to that, psychology also teaches people to help empathize others and use the knowledge they have to bring harmony among others. Concluding Sentence: In a nutshell, psychology assists in solving problems and handling conflicts. Conclusion : These are the benefits of learning psychology. It is true that there is no one who is born into this world as a psychologically whole person, but a person can be cultivated into one. Learning psychology plays a major part in this. That is why it is also said as ‘the science of soul’. Understanding of human behavior and use of knowledge learned from psychology helps a person in many ways in their daily life. Thus, the need to learn psychology is indeed very important.

Turbocharger Petrol Engine - Free Essay Example

Sample details Pages: 16 Words: 4820 Downloads: 9 Date added: 2017/06/26 Category Transport Essay Type Research paper Did you like this example? The quest for higher efficiency of the internal combustion engine will always be pursued. Increasingly stringent emission regulations are forcing the manufacturers to downsize on engine displacement and increase the specific power. By adding the turbocharger, the air flows through the engine and hence specific power can be increased. Don’t waste time! Our writers will create an original "Turbocharger Petrol Engine" essay for you Create order The advantage of a small turbocharged engine over a naturally aspirated (NA) engine of a similar power is that it is lighter, having better part load efficiency when operating at the same load, while producing less emission. The objective in this study is to investigate a turbocharger in a naturally aspirated engine and testing the engine before the installation of the turbocharger. Boost refers to the increase in the manifold pressure that is generated by the turbocharger in the intake path or specifically that exceeds the normal atmospheric pressure. This study also aims to develop a strategy for the control of boost for the engine. 1.0 Introduction 1.1 Background Turbocharged spark ignition engines have been around since the 1970s, but their popularity outside the motorsport sector has been small until the recent advances in engine control. The lack of popularity could partly be due to the drivability issues associated with early turbocharged engines. The engines response to a sudden increase in drivers demand was delayed due to a turbocharger lag. The lag was then usually followed by a rapid increase of power which resulted in loss of traction and possible loss of control over the car. The developments made in the electronic control and management of internal combustion engine made it possible to overcome most of these drivability limitations. Passenger vehicles with turbocharged SI engines are now becoming more common. A number of companies such as Audi and Volvo now offer different passenger vehicle models with turbocharged SI engine whereas Mercedes offers supercharged and turbocharged engines. The operating principle of the turbocharger is to use the energy recovered from the exhaust gases to force more air into the combustion chamber. This increases the amount of oxygen in the combustion chamber and hence more fuel can be burned and more power can be produced. Therefore a turbocharged engine can produce more power than a similar sized naturally aspirated engine. It is claimed that the displacement of the turbocharged engine can be reduced by up to 40% relative to NA engine, without compromising power output. Thus the turbocharged engine could be smaller, lighter and more fuel efficient as well as produce less emissions. 1.2 Aim To design and specify turbocharger in a Vauxhall 2.2 litre engine 1.3 Objectives: Critical literature review of the project. To investigate turbo system, develop a system for the Vauxhall 2.2, produce drawings and design. Testing the engine before installation of turbocharger To investigate and develop strategy for control of boost for the engine over a wide range of condition. 2.0 Initial Critical Review of Literature This project is related to the turbocharging of a four stroke petrol engine. In this discussion a turbocharged four stroke diesel engine will also be discussed briefly and the differences will be highlighted. However, it omits to discuss two stroke engines due to their different gas exchange processes. Supercharging The term supercharging refers to increasing the air density by increasing its pressure prior to entering the cylinder. This allows a proportional increase in the fuel that can be burned and hence raises the potential power output. Three basics categories are used to accomplish this. The first is mechanical supercharging where a separate pump or compressor, usually driven by power taken from the engine, provides the compressed air. The second method is turbocharging, where a turbocharger, a compressor and turbine on a single shaft is used to boost the inlet air density. The third method is pressure wave supercharging which uses wave action in the intake and exhaust systems to compress the intake mixture. The main advantage of turbocharging as opposed to supercharging is that turbocharging uses the energy in the exhaust gas that would have been lost. Supercharging uses power from the engines crank shaft and thus less power is available for propulsion Turbocharging The author acknowledges that the theory represented in this section is extracted from Watson and Janota (1982). The exhaust driven turbocharger was invented by a Swiss engineer named Alfred Buchi, his patent applied to a diesel engine in 1905. It took a very long time to establishe a turbocharger, but it is now proved that their characteristics are suited to the diesel engine, the reason being that only air is compressed, and no throttling is used. A turbocharger consists basically of a compressor and turbine coupled on a common shaft. The exhaust gases from the engine are directed by the turbine inlet casing on the blades of the turbine and subsequently discharged to atmosphere through a turbine outlet casing. The exhaust gases are utilized in the turbine to drive the compressor, which compresses the air and directs it to the engine induction manifold, to supply the engine cylinder with air of higher density than is available to a naturally aspirated engine. Figure1: Automotive Turbocharger Since diesel engines having no knock limitations, the maximum allowable boost on CI engines depends only on the mechanical strength of the engine. On an SI engine, the boost pressure is limited by knock. Thus if boost pressure is high on SI engines, the compression pressure must be low, high octane number fuel must be used or ignition timing must be retarded. Turbocharger Theory The operating characteristics of turbo machines such as turbines and compressors are totally different from the reciprocating internal combustion engine. The most common turbocharging assembly used in the automotive industry is made up of radial compressor coupled to radial turbine. Between the two is a wide supporting plain journal bearing, because an ordinary roller bearing would not survive the high rotational speed of up to 25000 rev/min of which a small turbine is capable. For racing application, ceramic ball bearings are being used more frequently. Axial turbine coupled with a radial compressor is a common configuration. Axial turbines are preferred for their superior efficiency to those of a radial turbine, but according to manufacturers radial flow turbines are simpler and cheaper to manufacture and also the operating range of radial flow compressors are limited to certain pressure ratios, because a high pressure ratio will cause the supersonic flow and cause shockw aves at the inlet, this will impair the efficiency of compressor. Turbocharging Diesel (CI) or Petrol (SI) engines Today turbocharged diesel engines are common but turbocharged petrol engines are rare. There are sound reasons, both technical and economic for this situation. The principal reasons stem from the difference between the combustion systems of petrol and diesel engines. The petrol engine uses a carburettor or fuel injection system to mix air and fuel in the inlet manifold so that a homogeneous mixture is compressed in the cylinder. A spark is used to control the initiation of combustion which then spreads throughout the mixture. This is because the mixture temperature during the compression must be kept below the self-ignition temperature of the fuel. Once the combustion has started it takes time for the flame front to move across the combustion chamber burning the fuel. During this time unburnt end gas is heated by further compression and the radiation from the flame front. If it reaches the self-ignition temperature before the flame front arrives, a large quantity of mixtu re may burn extremely rapidly producing severe pressure waves in the combustion chamber. This situation is commonly referred to as knock and may result in severe cylinder head and piston damage. This is due to the fact that the compression ratio of the engine must be low enough to prevent knock occurring. In the CI engine cylinder, air alone is compressed. Fuel is sprayed directly into the combustion chamber from an injector only when combustion is required. This fuel self-ignites as in a diesel engine the compression ratio must be high enough for the air temperature on compression to exceed the self-ignition temperature of the fuel. As injection takes time, only some of the fuel is in the combustion chamber when ignition starts, and since much of this fuel is not as damaging as the knocking situation in a petrol engine. The maximum CR of the petrol engine, but not the diesel engine, is therefore limited by the ignition properties of the fuel. The minimum CR is limited by resulting low efficiency. Turbocharging results not only give a higher boost pressure, but a higher temperature. Unless the compression ratio of a petrol engine is reduced the temperature at the end of compression stroke will be too high and the engine will knock. The engine may remain knock free under mild boost but only because there should be a sufficient safe knock free margin, or a fuel of higher self-ignition temperature/octane number has been used. Thus the potential power output of a turbocharged petrol engine is limited. The diesel engine has no such a limitation and can therefore use a much higher boost pressure. Petrol engines cost substantially less to produce than diesel engines of equivalent power output. The cost of the turbocharger on a diesel engine is more than offset by reduced engine size required for a specified power output (with the exception of very small engines). This situation will rarely occur in the case of petrol engine. Energy Available In the Exhaust Gas: Figure 2 shows the ideal limited pressure engine cycle in terms of pressure/volume diagram for the naturally aspirated engine. Superimposed is a line representing isentropic expansion from point 5, at which the exhaust valve opens, down to the ambient pressure (Pa) which could be obtained by further expansion if the piston were allowed to move to point 6. The maximum theoretical energy that could be extracted from the exhaust system is represented by the shaded area 1-5-6. This energy is called as blow-down energy. Figure2: Naturally Aspirated Ideal Pressure Limited Cycle (Watson and Janota,1982) Considering the supercharged engine, the ideal four stroke pressure/volume diagram would appear as shown in figure, where P1 is the supercharging pressure and P7 is the engine back pressure in the exhaust manifold. Process 12-1 is the induction stroke, during which fresh charge at the compressor delivery pressure enters the cylinder. Process 5-1-13-11 represents the exhaust proc ess. When the exhaust valve first opens (point 5) some of the gas in the cylinder escapes to the exhaust manifold expanding along line 5-7 if the expansion is isentropic. Thus the remaining gas in the cylinder is at P7, when the piston moves towards the TDC, displacing the cylinder contents through the exhaust valve into the exhaust pipe against the back pressure. At the end of the exhaust stroke the cylinder retains a volume (Vcl) of residual combustion products, which for simplicity can be assumed to remain there. The maximum possible energy that could be extracted during the expulsion stroke will be represented by area 7-8-10-11, where 7-8 represents isentropic expansion down to the ambient pressure. Figure3: Turbocharged Ideal Pressure Limited cycle (Watson and Janota, 1982) There are two distinct areas in figure 3 representing energy available from the exhaust gas, the blow down energy (area 5-8-9) and the work done by the piston (area 13-9-10-11). The maximum possible energy available to drive a turbocharger turbine will clearly be the sum of these two areas. Although the energy associated with one area is easier to harness than the other, it is difficult to devise a system that will harness all of the energy. To achieve that, the turbine inlet pressure must rise instantaneously to P5 when the exhaust valve opens, followed by isentropic expansion of the exhaust gas through P7 to the ambient pressure (P8=Pa). During the displacement part of the exhaust process, the turbine inlet pressure must be held at P7. Such a series of process is impracticable. Considering the simpler process in which a large chamber is fitted between the engine and the turbine inlet in order to damp down the pulsating exhaust gas flow. By forming a restriction to the flow, the turbine may maintain its inlet pressure at P7 for the whole cycle. The available work at the turbine will then be given by area 7-8-10-11. This is the ideal constant pressure system . Next consider an alternative system, in which a turbine wheel is placed directly downstream of the engine close to the exhaust valve. If there were no losses in the port, the gas would expand directly out through the turbine along line 5-6-7-8, assuming isentropic expansion. If the turbine area were sufficiently large, both cylinders and the turbine inlet pressure would drop to P9 before the piston had moved significantly up the bore. Hence the available energy at the turbine would be given by area 5-8-9. This can be considered the ideal pulse system. The system commonly used and referred to as constant pressure and pulse are based on the above principles but in practice they differ from these ideals. Constant Pressure Turbocharging In constant pressure turbocharging exhaust ports from all the cylinders are connected to a single exhaust manifold, whose volume is sufficiently large to dampen down the unsteady flow entering from each cylinder. When the exhaust valve of a cylinder opens, the gas expands down to the (constant) pressure in the exhaust manifold without doing useful work. However, not all of the pulse energy is lost. From the law of conservation of energy, the only energy actually lost between the cylinder and turbine will be due to heat transfer. With a well-insulated manifold, this loss will be very small and can be neglected. Consider what happens to the gas leaving the cylinder, expanding down into the exhaust manifold, and then flowing through the turbine. At the moment of the exhaust valve opening, the cylinder pressure will be much higher than the exhaust manifold pressure. During the early stages of valve opening (when the effective throat area of the valve is very small) the press ure ratio across the valve will be above the choked value. Hence gas flow will accelerate to sonic velocity in the throat followed by the shock wave at the valve throat and sudden expansion to the exhaust manifold pressure. Due to the turbulent mixing and throttling, no pressure recovery occurs. The stagnation enthalpy remains unchanged and hence flow from the valve to turbine is accompanied by an increase in entropy. As the valve continues to open the cylinder pressure will fall and flow through the valve which becomes subsonic. The flow will continue to accelerate to the valve throat and then expand to a pressure in the exhaust manifold. The energy available to useful work in the turbine is given by isentropic enthalpy change across the turbine, whereas the actual energy recovered is given by the enthalpy change across the turbine. Clearly it is a lack of recovery of the kinetic energy leaving the valve throat and throttling gases that lead to poor exhaust gas energy utilization with the constant pressure system. If the exhaust manifold is not sufficiently large, the blow down or the first part of the exhaust pulse from the cylinder will raise the general pressure in the manifold. If the engine has more than three cylinders, it is inevitable that at the moment when the blow down pulse from the cylinder arrives in the manifold, another cylinder is nearing the end of its exhaust process. The pressure in the latter cylinder will be low; hence any increase in exhaust manifold pressure will impede or even reverse its exhaust processes. This will be particularly important where the cylinder has both intake and exhaust valves partially open and is relying on a through-flow of air for scavenging of the burnt combustion products. There are some advantages and disadvantages of using a constant pressure system: Conditions at the turbine entry are steady with time. Therefore losses in the turbine that result from unsteady flow are absent. A single entry turbine may be used, eliminating end of sector losses. Single turbocharger can be used on all multi-cylinder engines, it will be a large turbocharger unit and since it is a large unit it will have low leakage losses and hence have higher efficiency. Turbines designed for constant pressure turbocharging have a high degree of reaction (50%) which, coupled with exhaust diffuser, brings additional gains in efficiency. From a practical point of view, exhaust manifold is simple to construct although it may be rather bulky, particularly relative to small engines with few cylinders. Transient response of the system is poor. Due to the large volume of gas in the exhaust manifold, the pressure is slow to rise, resulting in poor engine response and making it unsuitable for applications with frequent load or speed changes. Pulse turbocharging Although the constant pressure system is commonly used on certain types of engines, the vast majority of turbocharged engines in Europe use a pulse turbocharging system. In the practical pulse system an attempt is made to utilize the energy represented by both pulse and constant pressure areas of figure 2. The objective is to make the maximum use of high pressure and temperature exist in the cylinder at the moment of exhaust valve opening, even at the expense of the creating highly unsteady flow through the turbine. In most cases the benefit from increasing the available energy will more than offset the loss in the turbine efficiency due to the unsteady flow. Now consider small exhaust manifold as shown in figure. Due to the small volume of exhaust manifold, a pressure build up will occur during the exhaust blow-down period. This results from a flow rate of gases entering the manifold through the valve exceeding that of gas through the turbine. At the moment the exhau st valve starts to open, the pressure in the cylinder will be 6 to 10 times more than the atmospheric pressure, whereas the pressure in the exhaust manifold will be close to atmospheric. Therefore the initial pressure drop across the valve is above the critical value at which choking occurs and the flow will be sonic. Further expansion of the gas to the exhaust manifold pressure occurs by sudden expansion at the exhaust manifold recovery occurs due to turbulent mixing. The stagnation enthalpy remains constant hence the flow from the valve throat is accompanied by an increase in entropy. Finally the gas expands through the turbine to atmospheric pressure, doing useful work. The out-flowing gas from the cylinder loses a very large part of its available energy in throttling and turbulence after passing the minimum section of the exhaust valve. If the ratio of valve throat area to manifold cross section area is very small then throttling losses are very large and pressure dro p across the valve is very large, during the initial stages of valve opening. Following further opening of the exhaust valve the cylinder pressure increases, reducing the throttling losses across the valve. The pressure drop across the turbine is now much larger, transferring the available energy to the turbine, which represents a much larger proportion of the available energy in the cylinder. At the end position of the valve opening the flow is sub-sonic and the throttling loss is reduced and is equivalent to the kinetic energy at the entry to the exhaust manifold. During the exhaust stroke, the flow process follows approximately the constant pressure pattern as described in the previous section. At the exhaust valve, the pressure in the exhaust manifold approaches atmospheric value. With pulse operation, a much larger portion of the exhaust energy can be made available to the turbine by considerably reducing throttling losses across the exhaust valve. The speed at w hich the exhaust valve opens to its full area and the size of the exhaust manifold become important factors as far as energy concerned. If the exhaust valve can be made to open faster, the throttling losses become smaller during the initial exhaust period. Furthermore, if the area of exhaust manifold is smaller than the rise in pressure of exhaust manifold will be faster, contributing to a further reduction in throttling losses in the early stages of the blow-down period. A small exhaust manifold also causes a much more rapid fall in pressure towards the end of the exhaust process improving scavenging and reducing pumping work. This discussion has therefore focused on the single cylinder engine connected to the exhaust manifold. However, in the case of a multi-cylinder engine this problem becomes more complicated. Because the turbocharger may be located at the one end of the engine, narrow pipes are used to connect the cylinders to the turbine to keep the exhaust manifold size as small as possible. By using the narrow pipes the area increase following the valve throat is greatly reduced, keeping throttling losses to a minimum. Scan dig7.2 Consider again a single cylinder engine, connected to a turbine by a long narrow pipe as shown in figure. Since the large quantity of exhaust energy becomes available in the form of a pressure wave, which travels along the pipe to the turbine at sonic velocity, the conditions at the exhaust valve and the turbine are not the same at a given time. Therefore the flow process at the exhaust pipe and at the turbine end, have to be presented separately as shown in figure. For simplicity, pressure wave reflections in the pipe are ignored. During the first part of the exhaust process, in the choked region of flow through the valve, the gas is accelerated to sonic velocity at the throat. Since the contents of the pipe are initially at rest at atmospheric pressure, sudden expansion takes place across the valve throat. However some of the kinetic energy is retained as dependent on the valve throat area to pipe cross-section area. As the valve opens further the pressure at the exhaust pipe entry rises rapidly. This is firstly because a certain amount of time is required for the acceleration of the outgoing gases, and secondly because the gases enter the exhaust pipe from the cylinder at a higher rate than they are leaving the exhaust pipe at the turbine end. The sudden pressure rise at the pipe entry is transmitted along the pipe in the form of a pressure wave and will arrive at the turbine displaced in time. This displacement is a function of length of pipe and properties of gas. The pressure drop across the valve is noticeably reduced due to the rapid drop in cylinder pressure and the rise in the pipe pressure and also because the valve throat area to pipe area ratio has increased. Both effects considerably reduce throttling losses. The velocity at the turbine end of the pipe is greater than velocity after the valve, due to the arrival of high pressure wave at the turbine end. In the subcritical flow region of blow down period, the pressure in the exhaust falls at the same time as that in the cylinder. The velocity at the valve throat is equal to the velocity in the pipe, since the valve is fully open. At the turbine exhaust gas expands to atmospheric pressure, doing useful work in the turbine. It has been established that the pulse turbocharging system results in greater energy availability at the turbine. As the pressure wave travels through the pipe, it carries a large portion of pressure energy and small portion of kinetic energy, which is affected by friction. The gain obtained through the use of a narrow exhaust pipe is achieved partly by reducing throttling losses at the early stages of the blow down period and partly by preserving kinetic energy. Thus the small diameter exhaust pipe is essential because this will preserve high gas velocity from the valve to the turbine. However if pipes are made too narrow, viscous friction at the pipe wall will become excessive. The optimum exhaust manifold pipe diameter will be a compromise, but the cross sectional area should not be significantly greater than the geometric valve area at full lift. The actual flow through a pulse exhaust system is highly unsteady and is affected by pulse reflections from the turbine and closed exhaust valves. It will be evident that effective time of arrival of a reflected pulse changes as per the engine speed. Hence the exhaust pipe length is critical and must be optimized to suit the speed range of the engine. The interference of reflected pressure waves with the scavenging process is the most critical aspect of a pulse turbocharging system, particularly on the engine with a very long valve overlap. Because of this phenomenon it is impossible to connect an engine with more than three cylinders to the same turbine without using a twin-entry turbine or introducing losses on the intake or exhaust processes. The advantage of pulse over the constant pressure turbocharging is that the energy available for conversion to useful work in the turbine is greater. The ideal pulse turbocharging must have following characteristics: The peak of blow-down pulse must occur just before the bottom dead centre of the cylinder, followed by a rapid pressure drop to below boost pressure. The boost pressure must be above the exhaust manifold pressure to aid the scavenging process during the valve overlap. The effectiveness of pulse system is governed by the gas exchange process and overall efficiency of the turbocharger under unsteady flow conditions. Pulse converters in turbocharging The pulse turbocharging system has been found to be superior as compared to the constant pressure system on the majority of todays diesel engines. In the previous section it is made clear that the pulse turbocharging is most effective when groups of three cylinders are connected to the turbine entry. When one or two cylinders are connected to a turbine the average turbine efficiency and expansion ratio tend to fall due to the wide spacing of exhaust gases pulses. To overcome some of these advantages pulse converter has been developed. Birmann was the first to use the term pulse converter. His main objective was to design a device that preserved the unsteady flow of gases from the cylinder during the exhaust and valve overlap periods, yet to maintain a steady flow at the turbine, so that it might be possible to achieve good scavenging and high turbine efficiency. For good scavenging he proposed a jet pump system, by using high velocity of gas issuing from a central nozzle to decrease the pressure in short pipes at the exhaust valves. The system shown in figure 8.1 has some disadvantages as following: Each nozzle must be larger than last which results in high manufacturing cost. The whole installation is bulky and complex. Because much of exhaust gases will pass through several ejectors and diffusers, the frictional and diffusion losses will be high. There is insufficient length between exhaust ports to permits efficient pressure recovery in the diffusers. The majority of pulse converters in use today are based on the concept of minimum energy loss, even if this means not only a loss of all suction effect, but also some pressure wave difference during scavenging. To avoid high mixing losses at the junction, the area reduction in the inlet nozzles is usually small (junction area 50% of pipe area), while the mixing length and plenum and often even the diffuser are omitted completely, as suggested by Petak (as cited in Watson and Janota, 1982). These simple pulse converters have the added advantage of adding little over-all length to the exhaust system. A typical example from a four stroke engine is shown in figure 8.4. The pulse converter is specified by the nozzle and throat area ratios. Clearly such a pulse converter will generate no suction, but the flow losses through it will be very much less than in more complex designs. Tests on a model pulse converters by Watson and Janota (1971) have shown that the area reduction at nozzles has to be severe to reduce pulse propagation substantially. The penalty accompanying large area reductions in the inlet nozzles is higher internal losses and hence reduces the amount of energy available for useful expansion through the turbine. In practice this means that the minimum possible area reduction is used, consistent with reasonable scavenging. It follows that the design of the pulse converter is a compromise between minimum losses and reduction of the pulse interaction between the inlet branches. The compromise adopted may vary from one engine design to another, depending on the amount of pulse interference, etc. 8.0 References Watson, N and Janota, M, 1982, Turbocharging the Internal Combustion Engine, MacMilan, Great Britain. Heywood, John, B, 1988,Internal Combustion Engine Fundamentals, McGraw-Hill Stone, R, 1992, Introduction To Internal Combustion Engine, MacMilan, Great Britain. Azzoni, P, Moro, D, Ponti, F Rizzoni, G, 1998, Engine and load torque estimation with application to electronic throttle control, SAE paper No. 980795, Society of Automotive Engineers. 9.0 Bibliography Notes posted by Dr Les Mitchell on studynet Report Writing guide posted by Dr. Rodney Day on studynet