Fiber Optics Essays (4499 words) - Optical Fiber, Fiber Optics

Fiber Optics Fiber optics produced by special methods from silica glass and quartz which replaced copper wire is very useful in telecommunications, long distance telephone lines and in examining internal parts of the body (endoscopy). Equipment for photography is available with all current fiber-optic endoscopes. Through a process known as total internal reflection, light rays beamed into the fiber can propagate within the core for great distances with remarkably little attenuation or reduction in intensity. In general, the methods of fiber production fall into three categories; (a) the extrusion method for synthetic fibers; (b) hot drawing of fibers from molten bulk material through an orifice; and (c) drawing of uncoated, coated and multiple fibers from assemblies of rods and tubes fed through a hollow cylindrical furnace. Three forms of fiber optics components have been proposed for the improvement of the image quality, field angle and photographic speed of various types of optical systems. These fiber optics elements, in the form of a field flattener, a conical condenser and distortion corrector, can be used separately or combined into a single unit called a "Focon". BOAZ? ?NVERSTES MAKNA M?HENDSL DEPARTMANI MALZEME DERS D?NEM PROJES YAZ OKULU 2000 ?ZET G?n?m?zde bakr tellerin yerini alan silikon camndan ve kristalinden ?retilen fiber optikler, telekom?nikasyonda, uzun mesafeli telefon hatlarnda ve insan v?cudunun i? ksmlarn inceleyen endoskopilerde kullanlmaktadr. Fotoraf ekipmanlarnda da b?t?n fiber-optik endoskoplara kullanlmaktadr. Tam i? yansma olarak bilinen ilem yoluyla, fiberin i?inde toplanan k nlar, uzun mesafeler boyunca iddetinde kk bir azalma ve bozulmayla yol alabilmektedir. Genellikle, fiber ?retimleri kategoridedir; Sentetik fiber ?retiminde dna ?karma methodu; Erimi d?kme maddelerden azlarna doru oluan fiberlerin scak ?izimleriyle, kaplanm,kaplanmam veya kark fiberlerin ?izimleriyle. ?eit olan fiber optik par?alar; g?r?nt? kalitesini, ?eitli optik sistemlerdeki alan a?s ve fotografik hzlar gelitirmek i?in dn?lm?t?r. Bu fiber optik elemanlar; alan d?zletirici, konik younlatrc ve sapma d?zenleyici ekillerindedir ve ayr veya "Focon" ad verilen ?nite i?in birlemi olarak kullanlabilirler. LIST OF FIGURES Figure 2.1 Photograph of the earliest bundle of uncoated aligned fibers Page 7 Figure 3.1 Core of a step index fiber Page 8 Figure 3.2 Schematic diagram of a typical fiber drawing Page 9 Figure 3.3 Preform manufacturing apparatus used in Silica-Quartz Page 11 Figure 3.4 Comparison of static,dynamic and spitial filtering imagery Page 12 Figure 4.1 Field flattener system of photography Page 13 Figure 4.2 Showing the image transmission through a conical fiber bundle Page 14 Figure 4.3 Fiber optics distortion correctors Page 14 Figure 4.4 Limiting resolution of Focon system Page 15 Figure 5.1 Single lens reflex camera Page 16 TABLE OF CONTENTS 1. INTRODUCTION 2. HISTORY OF FIBER OPTICS 3. WHAT IS FIBER OPTICS? 3.1 WHAT IS SILICA? 3.2 WHAT IS QUARTZ? 3.3 WHAT IS ENDOSCOPIC PHOTOGRAPHY? 4. ENDOSCOPIC PHOTOGRAPHY ELEMENTS 4.1 FIELD FLATTENER 4.2 CONICAL CONDENSER 4.3 DISTORTION CORRECTOR 4.4 FOCON RESOLUTION 5. ENDOSCOPIC PHOTOGRAPHY TECHNIQUES 5.1 COLOUR PHOTOGRAPHY WITH FIBRE-OPTIC ENDOSCOPES 5.2 CINE- ENDOSCOPY 5.3 CLOSED CIRCUIT COLOUR TELEVISION ENDOSCOPY 5.4 GASTRO-CAMERA EXAMINATION 6. CONCLUSION 7. REFERENCES 8. APPENDIX 1. INTRODUCTION The technology of fiber drawing for nonoptical applications is old and fairly standard. Very-small-diameter glass and quartz fibers were made as early as by Faraday. In the early stages of the production of glass fibers on an industrial scale, the main application of the fibers was envisaged in the textile industry. More recently, they have been used for insulation against sound, heat and electricity. Presently, very fine fibers are being made of materials such as glass, quartz, nylon, polystyrene, polymethylcrylate. Of these, glasses, quartz and plastics are preferred for optical use because of their higher visible light transmission, longer thermal working range, better surface characteristics and mechanical strength. Furthermore, it has been shown that glass fibers can have greater tensile strength than can be expected from the bulk material. 2. HISTORY OF FIBER OPTICS The conduction of light along transparent cylinders by multiple total internal reflections is a fairly old and well known phenomenon. It is entirely possible that grecian and other ancient glassblowers observed and used this phenomenon in fabricating their decorative glassware. In fact, the basic techniques used by the old Venetian glassblowers for making ?millifiore' form an important aspect of present-day fiber optics technology. However, the earliest recorded scientific demonstration of this phenomenon was given by John Tyndall in 1870. In demostration Thyndall used an illuminated vessel of water and showed that, when a stream of water was allowed to flow through a hole in the side of the vessel, light was conducted along the curved path of the stream. In 1951 when A.C.S. van Heel in Holland and H.H. Hopkins and N.S. Kapany studied on the transmission of images along an aligned bundle

How to handle work when youre depressed

How to handle work when youre depressed Work can be challenging in even the best of circumstances- but when you’re depressed and not feeling your absolute best, getting through each workday can be a real struggle. Many folks grapple with depression in both their personal and professional lives, and it can make getting through each day and handling daily responsibilities difficult. According to a recent study by The National Institute of Mental Health (NIMH), â€Å"an estimated 16.1 million adults aged 18 or older in the United States had at least one major depressive episode in the past year. This number represented 6.7% of all U.S. adults.† The NIMH defines a major depressive episode as â€Å"a period of two weeks or longer during which there is either depressed mood or loss of interest or pleasure, and at least four other symptoms that reflect a change in functioning, such as problems with sleep, eating, energy, concentration, and self-image.†Depression in the workplace is a significant issue- both f or employees and employers. Mental Health America recently reported that â€Å"Clinical depression has become one of America’s most costly illnesses. Left untreated, depression is as costly as heart disease or AIDS to the U.S. economy, costing over $51 billion in absenteeism from work and lost productivity and $26 billion in direct treatment costs. Depression tends to affect people in their prime working years and may last a lifetime if untreated.†Furthermore, a significantly higher percentage of adults suffer from minor or moderate depressive episodes. Although they typically include less pervasive symptoms, it can nonetheless make it hard to handle work and a spiraling effect can result- you feel depressed, which effects your ability to work, which makes you more depressed, and so on.Are you among the millions of Americans who suffer from depression? If so, then you’re not alone and there is a way forward- use the following strategies to help you learn to hand le work when you’re depressed.Don’t ignore the signs.If you’re struggling at work, try your best to recognize the signs that it might be due to depression.Are you feeling tired and lethargic throughout the day for no reason?Are everyday tasks- things that you used to do before with ease- becoming increasingly more difficult for you to handle and complete, or have become completely overwhelming for you?Is interacting with others at your workplace, or working collaboratively on team-based projects, becoming so uncomfortable or unappealing to you that you avoid contact or social interactions with colleagues at all costs?Do you find that your self-care routine is falling by the wayside?Are you noticing negative changes in your overall mood and attitude throughout the day?Has your productivity at work dipped?Do you find yourself missing work, coming in late, or leaving early more often?The truth is, any one or combination of these signs could be an indication that yo u’re suffering from depression. If you answered yes to any of these questions, the first step is to acknowledge that depression might currently be an issue for you.Assess your needs.As previously mentioned, there are varying degrees of depression that an individual can experience, and every person has their own unique symptoms, coping mechanisms, and needs. If you’ve made the determination that you’re suffering from depression- whether its mild or more profound- a good idea is to try and take an honest self-assessment and mental inventory regarding how it’s affecting your life. The last thing you want to have happen is to have your depression take complete control of your life and adversely affect your job situation- which can make your condition worse.Once you’ve determined how your depression is affecting you at work, try to assess your needs. Do you need to simply recalibrate, get organized, and wrap your head around your work responsibilities i n a new and fresh way? Do you need to make some behavioral and lifestyle changes in an effort to enact positive change? Or do you need additional outside help? Once you’re able to make a determination about what you need in order to effect change in your life and make the struggle a bit easier, you’ll be in a better position to choose the right steps for you.Seek help if needed.Do you think that you may need some guidance from others- perhaps friends or family, trusted colleagues, or professional help? The first thing to realize is that this isn’t a personal failure on your part. Many competent and functional adults suffer from depression, and there’s no shame or stigma in reaching out for help. Depression is a heavy weight to carry around on your own- seeking help from others can help ease the burden and allow you to focus on working towards an effective life solution.Explore workplace options.Many progressive workplaces offer benefits packages that incl ude mental health services- from finding the right professional help to meet your needs to financial coverage for associated costs. You may also be eligible to take paid time off from work to focus on getting help and getting better. Contact your HR representative to learn all of your options, which will help you formulate the best strategy for dealing with your depression.You are under no obligation to disclose a private health concern like depression to your colleagues and coworkers. That said, many people chose to be honest and up front about their depression and are met with sensitivity, guidance, and understanding, which can be an incredibly supportive and encouraging thing to have at a time when you need it most. The choice on how to handle disclosure is completely yours.Don’t just ignore your depression.How many problems in your life get better by simply ignoring them? If you feel that you’re experiencing depression at work and it’s affecting your ability to do your job, your best bet is to not ignore it and to use the steps outlined above to try and make some positive changes. Don’t forget- you’re not alone and your situation is not insurmountable. With a little proactive effort and the courage to effect positive changes in your life, you can go beyond learning how to handle depression at work. Instead, you can truly thrive.

Women finding their identity in the modern world Essay

Women finding their identity in the modern world - Essay Example The author correctly points out that the world as young women see it today is something that was not there before 1950s or before the feminist movements. Rosen maintains that young women today cannot even identify with the 1950s era when life of women revolved around home, husband and kids. Various feminist movements, ideologies, and objectives have changed the landscape of rights for women. This change was seen as "the most powerful challenge to the feminine mystique," i and changed the way things were in women workforce increasing their participation in economic activities. It was during the 1950s that young women slowly "rejected the world of their mothers" and because of this change, this generation was termed anti-motherhood. The various changes in feminist movements have been witnessed over the decades. In the 1950s since feminism was still new, women had adopted the rather ill fitting tools to compete with men. They had become sexually, socially and intellectually rebellious but over the years, they realized that these tools were not helping them with their objectives. Rosen notes that during the 1970s, FBI got involved with feminism movement in order to stifle the latter. The paranoia had spread far and wide and feminist politics had become a major party of US political scene. Many feminists had become wary of government's interference as Rosen states: "Still, in my wildest flights of paranoia I never imagined the extent to which the FBI spied on feminists or how many women did the spying"ii. It was believed that FBI had recruited women informers to tip them off about such subversive aims as: "They wanted equal opportunities that men have in work and in society" iii. Many people saw feminist activitie s as a threat to internal security as Hoover was found saying: "Inter woven with its goals for equal rights for women is the advocation of violence to achieve these goals," that he saw as a threat to internal security iv. Thus FBI files contained information on feminist activities and agenda as one operative explained: "This movement has no leaders, dues, or organizations"v. The most disturbing aspect of FBI involvement was that it had a negative impact on solidarity of feminists. Some of the women would accuse each other of being informers thus hurting their bond of sisterhood to the effect that "feminists sometimes found it easier to accuse one another of being informers than to accept the inevitable differences among them that, even without the FBI, would naturally result in different feminist perspectives and different ideas of sisterhood"vi. Such differences resulted in the complete dissipation of feminism's objectives. These disagreements grew to the extent that by the mid-1970s, this movement "was everywhere and nowhere" vii. This means that during this time feminist movement was suffering from diffusion and misunderstanding. Many people felt that feminism was all about becoming a super-woman who cared about nothing and no one except her own dreams and herself. That was certainly not good for the movement as Rosen explains: "when Americans took a good hard look at this narcissistic superwoman who embraced the values of the dominant culture, they grew anxious and frightened, for they no longer saw loyal mothers and wives who would care for the human community, but a dangerous individual, unplugged from home and hearth, in other words, a female version of