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Overcoming Procrastination/Resources

Wikipedia articles
From Wikipedia, the free encyclopedia:
 * Academic procrastination
 * Dynamic inconsistency
 * Decision making
 * Decision theory
 * Getting Things Done
 * Goal (management)
 * Leadership
 * Skurfing

Methods used for overcoming procrastination

 * Autosuggestion
 * Hypnotherapy
 * Neuro-linguistic programming
 * Personal development
 * Self-help
 * Silva method

Web books

 * Psychological Self-Help; by Clayton E. Tucker-Ladd; Mental Health Net.   Click here to turn directly to the section on procrastination.

Web articles

 * Causes of Procrastination; University of Houston Counselling Services
 * A Company’s Number One Killer: Procrastination (causes and cures); by Donald L. Caruth, Ph. D. and Gail D. Handlogten-Caruth
 * Deadlines and Procrastination Don’t Mix; National Seminars Group
 * Procrastination (causes & cures); Tutoring Times. Penn State LRC
 * Procrastination: Habit or Disorder?; by Jenny Maryasis
 * Putting things off (procrastinating); Keele University Student Support Division
 * Overcoming Procrastination; by Steve Pavlina
 * Overcoming Procrastination; (University of Texas at Austin handout in PDF format. Click this for Word format.)
 * Design Your Own Anti Procrastination Plan; (University of Texas at Austin handout in PDF format. Click this for Word format.)
 * 7 Little Known Goal Setting Tips!
 * Some Facts Psychologists Know About… PROCRASTINATION; University of Cincinnati Psychological Services Center (Broken link)
 * Stand and Deliver (causes of procrastination); by Maia Szalavitz. Psychology Today
 * Procrastination: Ten Things To Know; by Hara Estroff Marano. Psychology Today
 * Tips on Managing Procrastination; Kwantlen University Counselling Services
 * Structured Procrastination; by John Perry
 * There's Always Tomorrow. Interview with Joseph.R.Ferrari; The Chronicle of Higher Education

Websites

 * Procrastinators Anonymous
 * Procrastination Support
 * Procrastination Research
 * Structured Procrastination

Bibliographies, reference lists

 * References for Books, Journal Articles and Theses about Procrastination (Procrastination Research Group).

Books

 * Awaken the Giant Within: How to Take Immediate Control of Your Mental, Emotional, Physical, & Financial Destiny; by Anthony Robbins. Simon & Schuster Adult Publishing Group, 1991. ISBN 0671727346
 * The Complete Idiot's Guide to Overcoming Procrastination; by Michelle Tullier. Alpha Publishing. 1999. ISBN 0028636376
 * Do It Now!: Break the Procrastination Habit; by William J. Knaus, with John W. Edgerly. Wiley, John & Sons, 1997. ISBN 0471173991
 * Getting Things Done: The Art of Stress-Free Productivity; by David Allen. Viking Adult, 2001. ISBN 0670899240
 * The Now Habit; by Neil Fiore. Tarcher, 1988. ISBN 0874775043
 * Overcoming Procrastination: Or How to Think and Act Rationally in Spite of Life's Inevitable Hassles; by Albert Ellis and William J. Knaus. Penguin Group (USA) Incorporated. 1979. ISBN 0451087585
 * Procrastination: Why You Do It, What to Do about It; by Jane B. Burka and Lenora Yuen, with Lenora M. Yuen. Perseus Publishing. 1990. Paperback, 227pp. ISBN 020155089X
 * The Seven Habits of Highly Effective People; by Stephen Covey. Simon & Schuster Adult Publishing Group, 2004. ISBN 0743272455
 * Unlimited Power: The New Science of Personal Achievement; by Anthony Robbins. Random House Publishing Group, 1987. ISBN 0449902803
 * Procrastination and Blocking: A Novel, Practical Approach; by Robert Boice. Praeger Publishers, 1996. ISBN 0275956571
 * Eat That Frog! 21 Great Ways to Stop Procrastinating and Get More Done in Less Time; by Brian Tracy. Berrett-Koehler Publishers, 2001. ISBN 1583762027

Audio Publications

 * The On-Time, On-Target Manager: How a Last-Minute Manager Conquered Procrastination; by Ken Blanchard and Steve Gotty, read by Brian Corrigan. HarperCollins, 2004. ISBN 0060584815
 * The Procrastinator's Handbook: Mastering the Art of Doing It Now; by Rita Emmett. Audio Renaissance. ISBN 1593978472

title: Overcoming Procrastination/Resources


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Overcoming Procrastination/Introduction

Procrastination or "task aversion" is the irrational delay of an intended course of action, even while expecting to be worse off for the delay (compare temporisation). The procrastinator deviates from the task, usually in favor of another more enjoyable (or less unenjoyable) activity. This behavior is pervasive throughout society - everyone procrastinates to some degree - but some people are so chronically affected as to be severely debilitated.

Procrastination is typically caused by the association of pain or discomfort with the prospective course of action; that is: stress. This may be physical (such as that experienced during hard labor or vigorous exercise) or psychological (such as in the form of frustration or anxiety). The task or the situation requiring the task may be perceived as dangerous, painful, overwhelming, difficult, tedious, uncomfortable, or boring; basically, unenjoyable; that is: stressful. Once habitualized, procrastination can be triggered at any time. Procrastination can also be a symptom of a serious psychiatric disorder such as depression or ADHD (attention-deficit hyperactivity disorder), and may be greatly reduced when the underlying condition is properly treated.

Traditionally, in the field of psychology, procrastination has been associated with perfectionism (a tendency to negatively evaluate one's own performance). However, research indicates that perfectionists are not any more likely to procrastinate, though they feel worse about it when they put things off.

The word procrastination comes from Latin, Pro, "in favor of", and Cras, "tomorrow".

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Overcoming Procrastination/Introduction


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Overcoming Procrastination/Consequences

Some of the Consequences:

 * Lost opportunities: for example, somebody else buys the car the procrastinator wanted because they put off making a simple phone call. Or somebody else patents an invention the procrastinator thought of first, because they never got around to patenting it themselves.

 * Tardiness: being late to meetings, showing up late at special events, and being late to pick up a date. Missing the beginning of the movie at the theater, and getting bad seats, because the procrastinator did not leave the house on time.

 * Missed deadlines: from failing a school assignment by not turning it in on time to missing a flight at the airport because the procrastinator talked on the phone too long.

 * Irresponsibility towards others: like failing to keep promises because they kept getting put off until later. Or causing others to be late for their commitments because the procrastinator didn't pick them up on time.

 * Lack of preparedness: such as when the basement floods unnecessarily because the procrastinator kept putting off installing a sump pump.

 * Poor performance: failing an exam, because the student waited until the night before the test to begin studying.

 * Career troubles: repeatedly missing deadlines on projects at work, making promotion unlikely and potentially leading to getting demoted or fired.

 * Unnecessary expenses: like having to pay late fees because the procrastinator didn't pay the bills on time even though they did have the money. Or having a huge liability from an automobile accident because the person at fault wasn't covered because they put off paying their insurance bill.

 * Financial difficulties: such as the inability to pay the bills due to putting off generating new sales or finding new customers for the business.

 * Medical problems: like having to make a painful visit to the dentist to have cavities filled or teeth pulled because the patient kept putting off brushing their teeth. Or having a heart attack because the victim kept delaying the start of their personal health program.

 * Dissatisfaction about oneself.

 * Dissatisfaction of others about one's procrastination. A spouse may even end the marriage because their partner put off getting a better paying job as promised.

title: Overcoming Procrastination/Consequences


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Overcoming Procrastination/Characteristics

Procrastination can be seen as both a behavior and the lack of a behavior. The behavior is the act of turning away and doing something else in place of what the procrastinator should be doing. The lacking behavior is of course the task or activity that the procrastinator should be working on, such as homework. There are three ways to procrastinate: skip it, do it last, and escape.

 * 1) Skipping it: here, even though the task is foregone forever, it is the program that is being put off. When a person skips brushing their teeth, they are putting off their whole "keep the teeth clean so they won't get cavities" program.  It's like they are saying "I'll start brushing my teeth tomorrow."
 * 2) Doing it last: easiest / most pleasant tasks tend to be done first. When there's a big job to do, and a long list of things to accomplish in order for that job to be completed, the tendency is to work on the simplest tasks.  As long as the items on the list are getting done, the job feels like it is being completed, and the procrastinator lulls themself into a false sense of security.  This approach becomes a problem when all the easy chores are done but there isn't enough time left to complete the hardest tasks because they were put off until last! Also, new alternative tasks may come up again and again, so that the main task is never started.
 * 3) Escape: the procrastinator instead does something they enjoy doing, choosing short-term gratification over long-term gain, at the cost of the benefits that they would receive from doing the task they put off. This takes their mind off the (stressful) task that they should be doing, or the situation they should be dealing with.  This can lead to a pattern of addiction, where the more the procrastinator escapes, the more guilty they feel about not doing what they are supposed to be doing, creating more stress to escape from, leading them to continue the alternate activity so they don't have to think about it.

But procrastination isn't necessarily the mere lack of doing something, it is something that is causing the procrastinator not to do it. In this sense procrastination isn't the behaviors done or not done, but is a behavior unto itself. As a distinct behavior, procrastination can be characterized in several ways...

Procrastination as poor judgement
At the core of procrastination is a faulty decision. Either the decision is made not to do something that should be done, or the decision is made to do something else. Since that is the wrong decision, and the person is aware of it but follows it anyway, that is poor judgment. A term for acting against one’s better judgement is akrasia. If the person makes the decision out of course with no thought to the outcome, then they are acting without thinking, and that too is poor judgement.

 * Poor judgement and laziness

 * Rest and relaxation is important to maintain health and to occasionally distance oneself from one's work so it can be seen more clearly or from a different perspective. But relaxation can be taken too far, and when it is, it's called laziness.  When resting beyond the need to maintain health interferes with responsibilities or life dreams, that is another example of poor judgement. There is much debate as to whether a value judgement such as laziness can be attributed to the procrastinator, since in many cases the procrastinator wishes to be active and productive but is held back by an inability to follow through.

 * Poor judgement and leisure

 * While leisure and recreation go hand-in-hand with rest and relaxation, and can provide therapeutic refreshment of body and mind, it becomes too much of a good thing when it interferes with what a person should be doing. Playing is useful for learning and can provide exposure to new things, and is an important component of open-mindedness, but when it is engaged in to the detriment of things needing to get done, it is yet another manifestation of poor judgement.  The procrastinator has chosen doing what they want to do over what they have to do.  It is often necessary to let work come before play.  But leisure doesn't have to be sacrificed completely: there's a section about scheduling fun breaks below.

Procrastination as being distracted
When something isn't enjoyable, it is very easy for a person to get distracted from a pending task. In this case, a procrastinator may feel blameless. The more susceptible a person is to distraction, the more prone the conditions are for procrastination.

If a person allows himself or herself to be distracted, and the distraction is not warranted (that is, it isn't more important than what what was being done), then that person has implicitly made the decision to procrastinate by choosing to do something other than what was intended.

The less thought that goes into making choices, the harder it is for a person to avoid the consequences of procrastinating. The more distracting elements (people, toys, etc.) there are in a person's immediate environment, the more opportunity there is for poor choices to occur.

Procrastination as a phobia
An irrational aversion to something is a phobia. Not only can phobias cause procrastination, a phobia can be a component of procrastination itself and therefore go unnoticed as a phobia. A strong and irrational aversion to something is usually a sign of a phobia.

Procrastination as bad habit
When the decision to avoid a task is repeated automatically—even when it is the wrong decision—making the wrong decision becomes habit; the decision maker has acquired a habit of making bad decisions. Keep in mind that a decision is implicit to every action taken, even if the person taking the action did not consciously decide anything.

Since habits are repetitive in nature, a habit cannot usually be overridden by a single decision: it takes a new habit to do this. A simple decision could easily be overwhelmed by the force of habit and therefore may need to be implemented as a habit itself before it can compete effectively with the old habit.

Procrastination as a complex
Unfortunately, procrastination isn't simply a habit, it is a complex pattern of recurring behaviors including emotions, thoughts, and actions. Many of these are habitual, and in order to get rid of them, each one needs to be replaced, circumvented, or deactivated by new habits; though not necessarily on a one-to-one ratio: sometimes a single habit can replace several others.

Procrastination as a symptom
Procrastination can be the result of a more serious underlying condition such as depression or ADHD. See below.


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Overcoming Procrastination/Causes

Procrastination is always based on a dysfunctional worldview, such as that "short term relief or pleasure is better than sacrifice for long-term rewards," along with irrational disregard for negative consequences. The procrastinator fails to engage in the appropriate course of action either due to a distraction of some sort or an inadequacy in their own behavior. Various distractions and incompetencies that can cause procrastination include, but are not limited to:

 * Addiction
 * Anxiety and fear
 * Arrogance, pride
 * Aversion
 * Bad habits
 * Discouragement
 * Disorganization
 * Distraction
 * Family problems
 * Fear of failure
 * Feeling overwhelmed
 * Frustration
 * Guilt
 * Ill-conceived goals and unconscious motives
 * Indecision
 * Lack of awareness
 * Lack of morals
 * Lack of time management skills
 * Low ambition
 * Low frustration tolerance
 * Low self-esteem
 * Low tolerance to stress
 * Objective conflict (competing goals)
 * Paranoia
 * Perception of difficulty
 * Phobia
 * Poor attitude
 * Poor self-control skills
 * Poor study skills
 * Rebellion
 * Resentment
 * Self-centeredness
 * Self-deception
 * Uncertainty

Expectancy-Value Theory

 * Laziness pays off today, work only tomorrow.

In motivational psychology, a mathematical formula can be used to determine what task should be pursued first. According to this model, we complete first those tasks which have the highest "usefulness"-value. This model is able to explain why we would rather be watching our favorite television program than writing the soon to be due term paper from your hardest college class, and it says that everybody is procrastinating, although each of us to differing degrees.

$$U=\frac{P\times V}{D}$$

where

 * U = the usefulness of the task.
 * P = Probability of profiting from the task
 * V = Value of the profit gained from the task
 * D = Delay between doing the task and receiving the reward for it

This formula is saying that, we (generally speaking) tend to prefer (depending on an individualized perception and perspective, that can not be fully generalized but can be normalized in test trials):
 * immediate rewards over delayed benefits
 * bigger rewards over smaller prizes
 * sure rewards over rewards that are only probable

The important question now is: Under what circumstances would someone put off their work? If the increase in U would be significant (e.g. when P, V or both values are high), every procrastinator stops procrastinating. By introducing an additional factor to the equation (S, the sensitivity of the subject toward the delay between action and reward), the behavior of different people could be compared.

title: Overcoming Procrastination/Causes


text: Overcoming Procrastination/GNU Free Documentation License


text: Template:Overcoming Procrastination

title: Template:Overcoming Procrastination


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Overcoming Procrastination/History

This book, Overcoming Procrastination, is an adaptation of the Revision as of 18:39, 8 March 2006 of the Wikipedia article, "Procrastination", authored by various Wikipedia contributors.

title: Overcoming Procrastination/History


text:
Overcoming Procrastination/Eliminating Procrastination

One would think that the solution to procrastination (not doing it) is its exact opposite: doing it! That the cure is doing the very thing that is being avoided.

[Note: We must be careful using the word "cure" in regard to procrastination. We ought to think of procrastination itself as a cure. Trying to "cure" procrastination is identical to trying to cure a fever. Fever is the body's attempt to "cure" an infection. A physician tries, instead, to eliminate the infection. Likewise, procrastination is an attempt (if misguided) to "cure" a personal difficulty. The underlying problem, for which a person uses procrastination as a solution, must be the focus. Curing procrastination--or concentrating on procrastination, then, distracts and delays an efficacious solution to the true emotional problem.]

Well it is, and then some. Since procrastination is the cause of not doing (rather than merely the lack of action), simply doing that which is being procrastinated may not be psychologically possible while the mental obstacle or technical problem causing the procrastination is in place. Also, as explained above, procrastination can be a powerful psychological force in its own right. Therefore, the procrastinator needs to get over, go around, or somehow plow through these mental barriers in order to get on with it. This is dependent upon the very nature of procrastination itself...

In essence, procrastination is a form of incompetence. To cure it is to eliminate it. Since incompetence is the opposite or lack of competence, the only way to eliminate it is to replace it with competence.

Personal competence comprises five elements: emotional strength, well-directed thought, time-management skills, control over habits, and task completion abilities. Therefore, most strategies for overcoming procrastination are based on improving these five skill areas, and involve: improving emotional control and adjusting one's underlying attitude, focusing attention and thinking rationally, learning executive (self-management) procedures like planning and scheduling, learning habit-changing methods, and acquiring better task completion and problem solving skills.

Increasing emotional control
To the extent that procrastination is an emotional problem, acquiring control over emotions brings the problem under control. Emotions are invoked by perception, which in turn is dependent on attitude, stress tolerance, and moods (which are simply sustained emotions that become trends). Therefore, by rebuilding or improving these foundations, emotional strength can be increased to handle the problems and opportunities encountered everyday, emotional or otherwise. There are both psychological and physiological methods of doing this.

Attitude adjustment
Personal attitude is the foundation of an individual's emotions. If a person believes that the world is out to get them and that they have been dealt a losing hand in life, they are likely to walk around with a frown on their face feeling sorry for themselves or being mad at everyone else, saying things like "why try anything at all, it won't matter anyways". But, on the other hand, if they believe that they have a great many things to be thankful for, that the world is a great place, and opportunity abounds, then they are more likely to work hard and greet everyone with a smile just because they feel good about themselves and others too.

Attitude isn't a static set of personal beliefs that a person is stuck with for the rest of their life. Attitude is an approach: at anytime, anyone can decide to look on the bright side of things, or not. The former engenders hope, enthusiasm, and joy, while the latter invites fear, loathing and misery. The choice on how to perceive the world is up to each person. Below are some of the perceptions of which a positive attitude may be comprised...

 * A positive mental attitude inspires ongoing action, especially when it includes a strong work ethic. Adopting an uplifting personal philosophy can provide the basis for such an attitude, especially when it emphasizes the importance of virtues. This usually entails pondering the meaning of life to determine what is important in life, and what approach to take.  A positive outlook on life engenders positive emotion in life, which in turn inspires action.
 * Dream envisioning is daring to imagine the desired future. The stronger it is (through repetition) and the more detailed its outcome is, the more compelling the dream becomes as a road map for action.  Making dreams come true is what success is all about, and a well-envisioned dream which remains "in view" at all times is one of the most powerful motivators there is.  That's why visionaries are called visionaries.  To live a life's dream is to think about it all the time, to continually think about everything in terms of that dream.
 * Determining self-worth on one's own rather than by the opinions of others makes for a more stable emotional base. Psychologists are divided between endorsing unconditional self-love, personal potential, and earned self-worth as the best approach through which to evaluate one's self-worthiness.  With unconditional self-love personal value is inherent: the individual holds themself in highest regard regardless of their actions, which is believed to provide the best environment to nurture the psyche for personal growth ("I am great because I exist").  When personal potential is the benchmark, it is one's personal skills and traits which matter, which focuses value on one's personal inventory (including ambition and willpower) in preparation for accomplishment ("I am capable of great things therefore I am worthy" and "I can accomplish anything I put my mind to, therefore I am worthy").  While in the earned self-worth model, self-worth is used as part of a reward structure:  one must do great deeds if one is to see themself as great ("I have done great things, therefore I am worthy").  But all three of these approaches to self-imaging work better than caving in to the criticisms of others.
 * Maintaining a positive mental voice means refraining from self-criticism, keeping critiques directed upon actions and strategies rather than one's person, and replacing self-putdowns with uplifting self-encouragement. The main character in the children's tale The Little Engine that Could provides a perfect example of this approach. While everyone else told the Little Engine that he would never make it up the mountain track, the Little Engine kept telling himself "I think I can, I think I can", even in the face of overwhelming odds, until his belief in himself carried him through.  Then, on his way down the other side of the mountain he shouted in victory "I knew I could, I knew I could, I knew I could!"  Now that's attitude in motion!
 * Rebounding after a defeat, like getting back in the saddle after falling off the horse, is usually better than giving up and not trying anything that big again. Volitional depression, a fancy term for discouragement, is where a person, after a big failure (like losing a fortune on the stock market, a divorce, going bankrupt, or a failed start-up company) retreats into themself or into an addiction (like drugs, becoming obsessed with the internet, collecting things, or engaging in sex as often as possible) instead of taking on another big project to go after success yet again.  The resilience to get back up after a failure and go for "it" again is much more conducive to success, and as a character trait is diametrically opposed to procrastination.  The average successful entrepreneur fails six times before making it big.  Keeping this in mind makes getting started again a lot easier, because it is a reminder that interim failure is temporary and is just part of the learning process of achievement -- winners keep going.
 * Counting blessings - One aspect of ‘looking on the bright side’ is inventorying opportunities, skills, and strengths, rather than bemoaning problems, inadequacies, and weaknesses. Seeing a situation as a ‘glass half full’ rather than a ‘glass half empty’, is the more inspiring approach. It is easy to take everpresent things for granted, while complaining about things that are missing. Remember the saying “I felt really bad that I had no shoes, until I met a man who had no feet!”  Appreciating those things that are usually taken for granted makes for a much better starting point than feeling sorry for oneself, plus it increases awareness of what resources there are to work with.

 * Building on strengths - Make a list of all the things you already master. Ask yourself how you got to be an expert in doing these things - and then, try to explain the differences between your "can't-dos" and "can-dos". To what feelings and circumstances are they attached? You may be able to apply the same approaches you used on acquiring your current skills to attain the new skills you need.
 * Building self-confidence - The only one source of self-confidence is enjoying success. But, the problem is that often you can only succeed against other people, e.g. by having equal or better marks than others. The problem is that you did procrastinate for such a long time that you are like a child which is learning to walk - but having put off the walking courses, it can only succeed when compared against a much younger baby. Stop comparing yourself with others - set your own goals! Get to know other people who find themselves in a like situation; you can learn from them that they did not fare better by comparing themselves with successful people.
 * Being progressive helps to put down your old feelings and habits. Remove old things from your room or apartment - they are associated with your old personality. If you possess something that vigorously reminds you of a sad, unlucky era - then get rid of it.

Another way to beat procrastination is by leading a healthy lifestyle. An unhealthy lifestyle makes a person much more susceptible to stress, which leads to feelings of being overwhelmed, which can lead to procrastination. By making a few adjustments to their lifestyle, like how much they exercise, a person can greatly increase how much stress they can handle...

Increasing stress tolerance
Some people are more susceptible to stress than others. In other words, those others are more tolerable to stress than those susceptible. The greater your tolerance, the more stress it takes to get you down. Stress falling below one's tolerance threshold is "no big deal", and is easy to deal with. What many don't realize is that this tolerance level is adjustable -- it can be strengthened...

 * Vigorous cardiovascular exercise increases resistance to stress, boosts the immune system, and improves oxygen supply to the brain and general mental performance (including intellectual performance, ability to focus, memory, etc.). Such exercise include walking, speed walking, running, swimming, biking, hiking, and aerobics.
 * Good nutrition, including nutrient supplementation, improves cognitive performance, boosts the immune system, and provides the brain with the precursors necessary for it to make the stress-coping neurotransmitters it needs. Abstaining from poor nutrition, such as by cutting down on sweets and sugar drinks, reduces hyperactivity, difficulty focusing, and obesity (which hampers the immune system, general performance, and proclivity to exercise).
 * Relaxation methods such as fractional relaxation, progressive relaxation, trance induction, and meditation reduce the effects of stress: tension and anxiety. The ability to remain calm and worry-free in the face of stressful situational factors is called self-composure. The ability to stay tension-free during a stressful situation, including using only as much energy and muscle tension required to complete motions, is called relaxed poise.  Combined together, these skills are called grace under pressure.

Enhancing mood control
Emotions, including moods, drive behavior. But our moods are our responsibility, and concerning each of them we can choose to feel that way or not. We can feel like throwing a tantrum and putting things off, or we can feel like doing something useful...

 * Being alert to one's own moods is preferable to not paying attention to what one is feeling (and consequentially to what one is doing because of these moods). The first step to changing a mood is to be aware of it.  Here is a simple ABC of bad moods to keep a look out for: angry, bored, cranky, dreadful, easily distracted, frustrated, grumpy, hurt, ill-tempered, justified, kicked, lazy, mean, nosy, obsolete, feeling like putting it off until later, feeling like quitting, robbed, selfish, tired, used, vexed, whipped, feeling like yelling at someone, zeroed in on (or zeroed out).  When you spot one, you can catch yourself, and change your emotional approach: your mood.
 * Positive filter is to retain the positive thoughts and actions and ignore or keep out the negative ones. Negative thoughts tend to build up and often become pervasive in one's life. When we continuously encourage positive thoughts and suppress negative ones, we develop a better outlook towards life and ourselves.
 * Changing expression (such as one's facial expression) can change a person's mood. When you feel good, you smile.  Conversely, and very useful for lifting one's own spirits is the fact that smiling (on purpose) generally makes people feel good. This is referred to in psychology as the 'facial feedback' hypothesis.  And smiles are contagious, so others can catch them from you, and in turn, you can catch "smilitis" back from them.  It's a synergistic arrangement.  And when we're feeling good, we are much more likely to feel like getting started.
 * Adjusting taste is changing how you feel about something, like learning to love what you hate. This is accomplished by changing how you think about it: dwelling on the benefits and good traits of an activity may lead to actually liking it.  Finding fun ways to do it, like turning it into a game, may also make it more enjoyable.
 * Self-psyching, or "psyching yourself up", is the self-administered pep-talk. You are your own coach delivering the motivational speech before the big game.
 * Managing fear - One way to overcome fear is to face it. Usually, the more exposure one has to a stressful stimulus, the more used to it he gets.  This is called desensitization.

Improving thinking
If you've ever wondered "What was I thinking?!" after doing something really stupid (like putting off a very important project to the last minute, or playing when you should have been studying), maybe you weren't thinking at all. Or maybe your reasons weren't very good, because you didn't put enough thought into them. These problems are the result of a lack of concentration. The solution to distractions and opportunities competing for attention involves improving concentration and how one concentrates: acquiring better focusing and decision-making abilities. Here also, there are psychological and physiological approaches.

Paying attention

 * Improving attention span can be as easy as taking nutrient supplements called nootropics. Below are a few nutrients which generally increase a person's ability to concentrate and enhance cognition in other ways as well, such as improving reasoning capacity and memory, and which are available for sale at nutrition shops, drug stores and online, and are often available at grocery stores:
 * DMAE (dimethylaminoethanol) - originally available as a prescription drug called Deaner, used for helping hyperactive children concentrate, DMAE is now available as a nutrient over the counter.
 * Choline - the precursor to acetylcholine, one of the brain's primary neurotransmitters essential for higher cognitive processes including reasoning and memory.
 * Vitamin B-5 - used as a cofactor in the brain's production of acetylcholine and essential for that process. Also a key component of the Krebs acid cycle, an important step in the aerobic metabolism of carbohydrates into chemical energy in the form of ATP (Adenosine triphosphate), and thus capable of increasing energy available to brain cells, improving mental stamina.
 * Focusing and refocusing -

 * Presence of mind -- It's not a coincidence that International Brain Awareness Week follows National Procrastination week.

 * Removing, or getting away from, distractions -- distractions often cause people to procrastinate, by presenting the option to do something else, or by triggering deviations. To prevent this from happening, minimize the chance of distractions occurring:
 * Sometimes the thing causing the distraction can be removed. If it is the TV or a video game, you can either turn it off, wear earplugs and/or hearing protectors, or go somewhere where you cannot hear it.  If you find yourself turning the TV or video game on and watching or playing when you really shouldn't, then perhaps the most effective approach would be to get rid of the TV and video game console (including the game cartridges) by giving them away, or taking them to the dump.  If it is a computer video game that has you hooked, maybe you can unload the program from your computer, and if that doesn't deter you, perhaps you can break the game disk!  Sometimes removing the source of the distraction isn't an option, usually when other people are involved...
 * If the distraction isn't allowed to be removed, or if the distractions are caused by people, such as by family or roommates, maybe you can find somewhere quiet in which to continue your project. If there isn't anywhere in your home, then consider somewhere outside, in your car, at the library, etc.  For some people, renting an office or apartment for a place to escape to, or moving out and living alone are options to consider.
 * Remove distracting thoughts. Perhaps you just can't begin your work because your mind is infested with distracting or energy-consuming thoughts, e.g. about a conflict with a friend or a "better" idea on how to use your time. Make a list of all these subjects - written down, you don't forget all your precious ideas and you can concentrate on them later. Never work on these thoughts first - they are the reason why you are procrastinating! If your hindering thoughts are too strong to have them removed or postponed by yourself, get the help of a clinical psychologist or a psychiatrist.

Thinking rationally

 * Thinking it through -- this is reasoning through an intended course of action, going over why each step needs to be done, and predicting what benefits will likely result if they are completed. Also, making a mental list of the consequences that will be suffered if the tasks are not completed is part of this exercise.  The virtual carrot and the stick. The goal here is to work out one's reservations and talk oneself into doing what needs to be done, taking care not to get stuck in transition (such as setting a time limit).
 * Consciously deciding what to do means switching off one's auto-pilot and actively applying intelligence with presence of mind: being aware of what you are doing and why, while remaining alert for opportunities to adapt and improve one's approach. Don't just go through the motions, actively think about what you are doing.

Improving problem solving skills
Try one or more of the techniques given in the problem solving article.

Acquiring self-management skills
Since the tendency to procrastinate on a project is roughly proportional to the difficulty of the project, and since its difficulty is relative to our skill in handling such projects, it follows that improving our self-management and organizing skills (e.g. by breaking the project down into small parts) decreases relative difficulty of the project and therefore also reduces its likelihood of intimidating us into procrastinating it. Simply put, simple jobs aren't scary. The more skilled you are at handling projects, the easier such jobs become.

Self-management systems provide simple procedures to help focus efforts and may assist you in mastering your projects and your situation. Nobody plans to fail, but many people fail to plan. Self-management systems help to keep plans in clear focus. Following are some components of a typical self-management system...

Goal vision
This is a form of goal setting, but more involved. It entails choosing the goal and writing down the goal statement as usual. Then the goal is mentally envisioned as vividly as possible, in as much detail as possible, as often as free time allows, and in every spare moment that becomes available. The more the goal is thought about and the actions for achieving it mentally rehearsed, the more likely the goal will become a driving force of the person's behavior. This method is best suited for important projects and life goals.

Planning

 * Goal setting - write down your goal statement. Be as detailed as you can.
 * Setting selection criteria - what features must your plan have to be successful? These are the plan's selection criteria.
 * Generating strategies - figure out as many ways as you can that the goal could be achieved. Research it if needed.  These are the action plans to choose from.
 * Selecting a course of action - based on your selection criteria, pick a strategy, your plan of action.
 * Develop the chosen plan in more detail - detail the plan down to the task level.
 * Putting the plan into action - see below.

Also, see the article on managing goals.

Scheduling
Schedules help organizing your daily and weekly life. Though some people profit more than others from a scheduled working life, two things are common to good schedules: They are be both feasible and flexible.

A feasible schedule allows you, for example, to begin working without forcing yourself to get up early. When studying for an important exam, beginning to study at 9 AM each morning is feasible. It allows you to stay up until midnight, depending on your sleeping needs, and lets you enjoy the social life in the evening. A typical student is mentally able to learn 6-8 hours per day for an exam, so he or she should schedule this amount of study time maximally.

A flexible schedule is a schedule which is immune to disturbances. You should schedule your work around such things as mealtime (in order not to be interrupted by colleagues which want to have dinner with you) or your favorite TV program which you may or may not watch. If you are working and a relative or a neighbor asks for your help, your schedule should allow for catching up with the lost time.

This said, a good schedule meets your abilities and provides enough reserve time. A schedule which you cannot trust is one you should not follow. In case of failure, you pay with your precious time.

Capturing tasks on a general to-do list
A general to-do list is a place to store tasks until you are ready to schedule them. It is typically a note pad that you keep handy (or a computer file that you keep open) for recording tasks as you think of them, to get them down in a central list where they won't be forgotten and can be easily referred to later. Tasks are regularly chosen from the general to-do list for inclusion in a more specific daily task list (see below).

Prioritizing tasks
Each task has a relative importance (cutting the grass is less important than studying for an exam). Tasks also have an expected duration (cutting the grass takes less time than studying for an exam). Most tasks are also time-sensitive (cutting the grass is flexible whereas studying must be complete before a fixed time). Prioritizing is the skill of reconciling these often conflicting attributes to determine which task ought to be performed first. In the context of a college exam, you could prioritize items as follows:
 * A: mandatory subjects. Knowing these certainly gives you a sufficient mark.
 * B: items which improve your understanding of the "A" topics. Studying them gives you probably, but not certainly, a good mark.
 * C: all other things. These will be studied last.

In an environment where more than one task is undertaken at once, and completion of some tasks is a prerequisite for starting other tasks, then a Critical path is formed of tasks which have the highest priority.

Making and using a daily task list
At the end of the day, before you go to bed, or at the very beginning of the day, just after you wake up, prepare a to-do list for the day. List all the tasks you need or plan to get done that day. Place the tasks in order of priority, or grade their priority in the left-hand column with numbers. Throughout the day, focus on executing each task on the list, one task at a time, highest priority tasks first. When you accomplish one of the items on the list, you check it off or cross it off.

An alternative method is a task list, where each task is in a category of urgent/not urgent and important/not important. Take a sheet of paper and draw a 2x2 column table so that you have four each corresponding categories.

→ Whatever is in the category urgent/important: do it now, by yourself.

→ Whatever is in the category not urgent/important: delay/procrastinate (and enjoy), till category one is empty

→ Whatever is in the category urgent/not important: try to find someone to do it for you or at least help you do it.

→ Whatever is in the category not urgent/not important: forget it or accomplish one of these tasks as a gratification for a task completed in the first category, as these tasks have a tendency to be of the type "cut grass", "have barbecue", "buy stuff I really like" etc..

The traditional method is to write these on a piece of paper with a pen or pencil, usually on a note pad or clip-board. Loose hole-punched paper is often used to allow such lists to be inserted into loose-leaf binders for record-keeping. However, numerous software equivalents are now available, and many popular e-mail clients include task list applications, as do most PDAs.

This is information about a wiki which one can edit as a personal organiser and store on the computer using just one file A wiki-style possible personal organiser

Keeping a journal
Making a record of what you have done (while you are doing it) can help you evaluate your performance and spot trouble-areas in your abilities and behaviors, like procrastinating. If you keep notes on task completion on your daily task lists, those can serve as your journal. Simply make note of situations that arose that you handled, and any tasks or significant activities that you did that were not on the list.

Changing habits
In one sense, procrastination is the habit of not getting started. It is not an action, so much as the lack of an action. It is not a habit, so much as the lack of a habit: the habit of getting started. If one acquires the habit of getting started, then not getting started is no longer an issue. Another word for "get started" is initiate. It is the exact opposite of procrastinate, as long as it is applied to the right task, and not an evasion.

At the same time, an ongoing problem of procrastination is a complex of bad habits. Luckily, old bad ways can be replaced by new good ways. Acquiring new good habits through self-training is key to eliminating the bad habits of evasion and putting things off.

The 21-day principle
There are commercial workbooks available concerning this "21-day rule", especially from Essi Systems, which provides workbooks. In general: If one can maintain a new habit for 21 days, the chances that this new routine would be forgotten are dim. This alludes to the detox or deprivation methods in curing drug dependencies.

Practicing replacement behaviors

 * Scheduling time for practice

 * Practicing new behaviors - mentally rehearse doing the task, and physically rehearse starting the task.

Maintain rituals
Often, some rituals - which may not be directly related with getting tasks done - can be helpful. For example one could wash the dishes and clean up the apartment as the very first thing after getting up in the morning. While doing manual tasks like this one already makes up a plan on what to do next. This is in contrast to answering e-mails - it might lead to distractions (websites, news, chatting with friends...). Rituals give you orientation, safety and the sense that something is achieved.

An example of a daily ritual:
 * Keep a list of several tasks to be done each and every day (or keep a list for working days, and a list for weekend days).
 * At first, keep that list very short (2 or 3 tasks). The last of these tasks is simple: Go to bed. Stay in bed. Read something if you cannot sleep.
 * Every task should take you at least 30 minutes. Always have a clock around you while working on this list.
 * Mix manual tasks (washing dishes, cleaning up, going out for a walk...) with "brainy" tasks (like answering e-mails, preparing the next exam...).
 * Under no circumstance change the sequence of the tasks. The first is always the first, the second always the second. It does not matter what you do between two tasks. It does not matter at which time you are doing which task. This gives you plenty of liberty. But it also means you are only going to sleep if you have fulfilled each of the tasks.
 * Do not disregard this ritual. Your only excuse is a medical certificate stating a sickness.

Completing tasks
The above strategies are aimed at preventing procrastination, or replacing it while on "down-time". But no defense is infallible, and because the opportunities, temptations, and tendencies to put things off may occur at any time and place, due to a myriad factors, this calls for a collection of front-line coping and problem-solving methods to deal with these factors head-on. Like a "tackle" box for tackling tasks and situations, right here, right now...

Snapping out of it
Procrastination is really nothing more than confined thinking. All you see is the tiny little box you are trapped in, and all you can think about is how to escape. But in reality, you are already free. Free to work on your life's dreams, free to plan, free to achieve. The trick to overcoming procrastination is to look to the horizon of your life (your dreams), travel there, and enjoy the journey along the way. Focus on that always, and procrastination fades away like an early morning fog.

Maintaining perspective
Thinking about your dreams in terms of what you are willing to do right now, rather than what you'll do or be someday is a call to action. Transformation is an active process. You are on a journey this very moment. The question is, are you on the right journey? If you aren't going anywhere, or you are heading in the wrong direction (towards failure because you are putting things off), simply adjust course, and live the life you want to live. And if that means making a sacrifice, then go for it! Put in the time and effort required, using all the methods you've learned about above, all the while keeping in mind what it is you are working towards. Always look to the horizon: focus on your dreams, how to make them come true, and actually make them come true one moment and one task at a time.

Maintaining grace under pressure
The most effective way to overcome fear is to face it. Veterans are generally more stable under combat conditions simply because they've been through it before. One method for overcoming fear of heights is practicing climbing ladders, for instance. Stepping up to the first rung, repeated over and over, then two, repeated, and so on, proceeding to the next level only after mastering the one before.

Thrill activities may be good training in this regard. Roller-coaster rides, river rafting, and skydiving can all lower sensitivity to perceived threats. Once you've jumped out of an airplane a few times, asking someone out on a date may not seem that intimidating anymore. Perhaps an easier way of getting over fear of talking to boys or girls is talking to them every chance you get.

Some drugs which are purported to cure phobias or treat anxiety have side effects that defeat the purpose if not used with extreme caution. Propranolol, for instance, a beta blocker which helps to turn off the fight-flight response has the side effect of causing depression, because it is also an acetylcholine inhibitor.

Tending the task list at all times
The task list doesn't do any good if it is not referred to, or if it is not updated frequently. Once using a task list and completing the items on it have become habit, placing a task on the list practically ensures it getting done. Relying continuously on this key tool is a core management skill and executive process. It is a standard method of operation in business for getting things done, and is a central component of competence. Frequently forgetting to do something may be a consequence of not writing it down (and keeping track of it) in the first place.

Focusing on one task at-a-time

 * Find the highest priority task, and then concentrate yourself on that one task and forget all the others. Only when you have finished the first, move on to the next item on the list.

 * Do something, but plan your time: Do not just "do something", but do something in a defined time frame. Wash the dishes for exactly 15 minutes, and write a letter for 30 minutes. Control your time with a timer (most modern cell phones have one); and fulfilling a (dreaded) task is a lot easier if you know how much time you'll spend.

Removing uncertainty
Often, a person will hesitate on or avoid a task because he or she just doesn't know where to begin. How to complete the task isn't obvious, therefore making the task undoable in its present form. The key here is task selection. Switch to the task's prerequisites: whatever other tasks need to be accomplished before this one can be started.

If you don't know what to do or how to do it, then your default task is to figure it out. If you don't know enough to solve a problem, then finding and learning the required information are the default tasks.

Dividing and conquering

 * Breaking a project down into its component pieces and subpieces will eventually reach a level of detail where the specific actions that need to be taken can be seen. Once action has started on a specific task, flow may take over and the project may seem like it takes on a life of its own and actually becomes fun.  And time flies when you're having fun.
 * Take bite-sized morsels -- rather than sit down to "write your book", write one page. Writing one page is easy.  When you are done with that page, then you can set about writing the next page. In general, try to plan your work in such a fashion that you've accomplished something in a 30 or 60 minute's time, not only a little bit of something. Or, said in a better example: Instead of just learning hours and hours of chemistry, you specialize on a subject - like "I have problems understanding pH values, so I'll read the relevant chapter about it. Then I make a pause." In this approach, you know that your ordeal has become manageable.

Easing into the task
You're faced with a task that will take you 20 hours, and you just aren't relishing it. Seen as one big step, the chore is rather ominous. Instead of approaching it like this, try committing to 5 minutes. Now the pressure is off. Five minutes is easy. During that five minutes you will likely see that your evasion was pointless, and that the activity isn't as bad as you thought it was. Once you begin a task and work on it for awhile, the initial stress goes away, and you are very likely to feel like continuing.

Stopping at the point of diminishing returns

 * Avoiding perfectionism saves a lot of time. Try to do sufficient works, not perfect ones - a start is a start. Perfectionists aren't any more likely to put things off than other procrastinators, but they are likely to spend much more time putting the finishing touches on a task than they need to. By avoiding perfectionism and by striving for "good" or at least "sufficient" work, you lower the bar of your expectations. The lower the bar, the greater the chance that you succeed - and having success is the only thing in the world that can give you a better self-esteem.

Feedback and record keeping

 * Check off tasks as they are completed -- in the left-hand margin of your task list, use check-marks to keep track of which tasks you have completed. This provides a visual indicator of progress.

Scheduling breaks
Most people will, under normal circumstances, work at their best if they take a 10 minute break from their work each hour. Also make limits on your total daily work - when you're learning for an exam, you can't learn more than 6 to 8 hours a day. Being a good student or co-worker does not force you to suffer from overworking or sleeplessness. If you can't adhere to a maximal working time per day, then you should learn to begin earlier instead of trying to work faster.

A lot of scientific work has shown that good learning - be it practical work that needs fine motorics of your hands or learning for a college exam - requires sleep, as the brain seems to fine-tune and rearrange what you've learned the day before. Try it out: Learn to juggle balls or other objects; and when you begin the next learning period the day after, you magically appear to have less trouble in spite of the fact that you did not practice during the night.

Remember: Like a musician has to play so that you hear the rests, you should work to let the pauses appear like pauses. "I didn't work" alone does not constitute a rest from work. It is the conscious doing of "anti-work" - when you did read texts to learn, then you don't read anything during your pause. When you worked half a day in your office, then escape your prison to enjoy the break.

Self-rewards
Another method of self-motivation is self-administered rewards - a method which reminds of reinforcement in psychology. In this approach, even the smallest accomplishment deserves an appropriate reward, due after a task is completed, not before. There are several approaches:

 * Applying a reward structure for spending given amounts of time working on a chore. For five hours of doing something you otherwise detest, make yourself a fine meal. For twenty hours, you go out for a movie, etc. You can even display your rewards symbolically: Take a post-it note, write down your reward, and with checkboxes define how many hours you want to work to achieve that reward. And remind yourself not to do the rewarding thing until you've filled all the checkboxes.
 * Assigning someone else to give out the rewards helps remove the temptation of taking the reward anyway. Of course they shouldn't be expected to provide the rewards - they should be unbribable, impartial people who effectively judge your efforts.

You should make a clear difference between the rewards and all the other things you receive (e.g. your meals at the cantina or watching the TV news). A good reward is something you enjoy and something you don't get every day. If the borderline blurs, a reward is no reward anymore; and so you tend to procrastinate even more because you get the "reward" anyway.

If you exercise a reward system strictly without cheating, there is a high chance that you'll be conquering your procrastination - this is because you get more and more accustomed to working and because you are needing less and smaller rewards over the time.

Recruiting peer support

 * Do your work in a group and start being used to tell your colleagues what you did and what you did not do. Start having friends you care for - and then, begin to fulfill their expectations. This works best if you are working together - being lazy on the group work often means losing your colleagues. Get a feeling for teamwork and that everyone has to fulfill their part. Working in a team is exciting, too. There are always ideas stemming from other minds, and by using them you can extend the scope of your own work without expending a lot of your own energy.

 * Form a group of Procrastinators Anonymous. You surely heard of other people who are "lazy". Now: Try to contact them. Suffering from procrastination means that one often is not respected by others; and so they are very shy to tell you about their problems. Telling others that you have a problem is the first part of any cure; it connects your inner world to the perception of your friends and family members. Telling others about your problems raises the expectations of your fellow human beings, and last but not least fulfilling expectations is something very rewarding.

Seeking professional help should always be considered in addition to the above options.


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Overcoming Procrastination/Chronic Procrastination

When procrastination grows so prevalent that it becomes a personality trait, its severity is said to be chronic. In this form of procrastination, the problem has become a generalized habitual self-destructive pattern. Putting tasks off has become a core habit. The chronic procrastinator cannot get anything accomplished on time, resulting in serious career struggles, persistent financial problems, and a diminished quality of life. Chronic procrastination may cause psychological disability and dysfunction in many dimensions of life, and may result in a persistent sense of shame and low self-esteem. It may be that the procrastinator never learned the habit of completing tasks from his or her parents, and since some scientists assume that every form of behaviour is a learned one, such an environment could have coined his or her habits. The solution is for the procrastinator to rebuild his behavior complex upon the foundation of a new core habit of taking action. Unfortunately, the procrastinator is prone to procrastinate from this too, so the condition of chronic procrastination usually continues until the procrastinator cannot bear it any longer, and seeks out help or spontaneously realizes the willingness and determination to change his or her ways.

Many individuals who consider themselves "chronic procrastinators" are actually suffering from an underlying mental health problem such as depression or Attention Deficit Disorder (ADD). These individuals often do not understand why they cannot "get it together", and can become resigned to a life of struggle, frustration, and underachievement. There is, unfortunately, widespread ignorance about this constituent to procrastination, even amongst mental health professionals, some of whom see procrastination as simply a "bad habit".

In addition, some people are predisposed to monotropism, a condition associated with autism in which there is a tendency to allocate attention to one task at a time, and to be less able than usual to multi-task or allocate segments of time for different priorities as may be needed. This may stem from many causes, including obsessional disorders and Asperger syndrome. To these individuals, tasks perceived as less important or less urgent may be excessively deferred behind other tasks which receive undue attention or priority.

These disorders can be treated with medication and psychotherapy, whereby the individual can learn new behaviors and achieve a greatly improved quality of life. Thus it is important for people who chronically struggle with debilitating procrastination to see a trained therapist or psychiatrist to see if an underlying mental health issue may be present.

Procrastination and addiction
Severe procrastination, and the intense desire to escape from it, can lead to addictions such as internet addiction or computer addiction. In this instance the individual has a compulsion to elude reality by surfing the web or playing video games (see Game addiction) or looking at pornography (see Pornography addiction).

Some of these relatively new phenomena are already being considered as valid psychiatric diagnoses by mental health professionals.


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User talk:Woodenrobot

Problem with image copyright
(You have not edited Wikibooks since December 2004, but despite this I will attempt to contact you here.)

About two years ago, you uploaded the Image:Buddha on white.jpg. It currently decorates the book Buddhist Philosophy. However, you never specified the source of the image, and I suspect that we do not have copyright permission to use the image. Please edit the page Image:Buddha on white.jpg and specify source and copyright information, or the image might be deleted. --Kernigh 01:59, 21 March 2006 (UTC)

title: User talk:Woodenrobot


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Muggles' Guide to Harry Potter/Magic/Locomotor

Overview
Used in the form "Locomotor object", e.g. "Locomotor trunk", this causes the named object to lift up and move as though the wizard casting the spell were carrying it.

Extended Description
This spell is used numerous times in the books; it is used whenever a wizard needs to carry a large load at about a walking pace. When the spell is cast on an object (usually a trunk), the object lifts, and follows the spell-caster.

Analysis
The Locomotor spell seems to be speed limited: in Harry Potter and the Order of the Phoenix, Tonks uses this spell to bring Harry's trunk downstairs to where the rest of the Advance Guard are waiting; but it is then strapped to a broom for the high-speed journey to London, which probably means that the Locomotor spell is not strong enough to keep the trunk with Tonks at speed. It is apparently capable of lifting things up stairs, as Professor Flitwick uses this spell to help him carry Sybill Trelawney's trunks back up to her tower room, after Professor Umbridge sacks her in Harry Potter and the Order of the Phoenix.

Greater Picture
Curiously, despite the apparent similarity to the spell Locomotor Mortis, first seen in Harry Potter and the Philosopher's Stone, the latter is the Leg-Locker jinx, meaning that the "locomotor" in that case must refer to the victim's legs. Clearly there must be some mental component that changes the effect from that of causing a body to move, as we would expect from a casual inspection of the jinx. We also note that the equivalent for moving a body, as seen in Harry Potter and the Prisoner of Azkaban, is Mobilicorpus.


text: Buddhist Philosophy/GNU Free Documentation License


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Adventist Youth Honors Answer Book/Household Arts/Laundering

1. Why is it important to read the labels in garments before laundering them?
The labels often include the manufacturer's recommended washing instructions as well as the types of material the garment is made from. Instructions often include:
 * Wash temperature
 * Rinse temperature
 * Ironing temperature, and sometimes ironing method.
 * If the article is only suited for dry cleaning
 * Drying method
 * Folding method
 * Hanging method

2. What is the proper way to prepare clothes for washing?
Remove all items from all pockets, zip-up any zippers, fasten snaps, and cover Velcro. Also, tie any strings back so they won't get tangled in the agitator or with other garments. Remove any pins, your name tag, and the "scribe" or "captain" tag from your Pathfinder uniform before washing it. Brush off any caked-on dirt. Turn permanent press and garments with silk-screened patterns inside-out.

Place small items and hosiery in a mesh bag before putting them in the washing machine. This will prevent small items from being flushed out with the rinse water, and it will help prevent runs in hosiery.

Separate your laundry into like items:
 * Whites from colors
 * Color-fast from colors that may run
 * Durables from delicates
 * Very dirty from lightly soiled
 * Lint givers (towels, sheets, flannels) from lint takers (corduroy, permanent press)

Wash these types separately, because each of the types of loads listed above needs different settings on the washing machine. Finally, pretreat any stains with a stain remover.

4. What precaution should be used when using chlorine bleach? What are the advantages of powdered oxygen bleach? Why should chlorine bleach and ammonia never be mixed?
Precautions: Bleach is a powerful chemical. It can burn your skin, and it can dissolve cloth. Do not get it on your skin; if you get it on your skin, wash it off right away. If you spill it on your clothing, rinse immediately. If too much bleach is used on cloth, the cloth will disintegrate. Bleach will remove dye, so it must not be used on anything other than white cloth.

Powdered Oxygen Bleach: The greatest advantage offered by powdered oxygen bleach is that it removes stains without the use of toxic chemicals. For some stains, it works even better than chlorine bleach. It brightens fabrics and can be used on upholstery and carpet. It is non-toxic to humans and animals, and it breaks down into environmentally friendly components when the oxygen is released (the release of oxygen is what removes stains).

Mixing Bleach and Ammonia: Bleach and ammonia should NEVER be mixed because doing so causes a chemical reaction that releases poisonous gases. The primary gas released is chlorine gas which was used as a chemical warfare agent during World War I. Chlorine gas is highly toxic. Other gases that can be released include nitrogen trichloride (which can explode in your face), and hydrazine (a component of rocket fuel).

5. What precautions should be taken when using liquid fabric softeners?
Liquid fabric softeners leave an invisible residue on the garments which prevents static cling, softens the fabric, and imparts a light fragrance. It should only be used in the rinse cycle when no soap is present in the water, because it will react with soap and leaving a sticky, visible residue which resembles lint. If your washing machine has a fabric softener dispenser use it and the fabric softener will be added at the right time in the cycle. Otherwise, you must add it yourself at the beginning of the rinse cycle. Be careful to not pour it directly on clothing, but rather into the water.

6. Know how to remove the following stains

 * Blood: If the blood is fresh, wipe it up with a sponge soaked in cool, salted water. Then rinse with clear water.  If the blood is dried, use diluted hydrogen peroxide (one part peroxide, nine parts water).
 * Chewing gum: Scrape off as much as possible first. This is easier if you cool the gum down with ice cubes first, as that makes the gum brittle rather than gummy.  If the item is washable, apply a little dry cleaning fluid and rinse it off. You may have to repeat this several times.
 * Crayons: Place the stained item in the freezer and leave it there until the crayon freezes. You can then literally break the crayon stain out of the garment.  If there is any residue left after this, place the item on a paper towel or a blotter.  Then place a second paper towel (or blotter) on top of the item.  Apply a warm iron.  This will melt the crayon, and the paper towels should soak up the stain.  Change the paper towels as often as is necessary.
 * Grass: If the garment is white, you may soak it in a solution of chlorinated bleach, then rinse and launder. Otherwise, apply methylate alcohol (wood alcohol) to the stain, rinse in warm water, and then wash.
 * Grease: Scrape away as much of the grease as you can.  Rub petroleum jelly into the stain, and then wash with a laundry powder or liquid detergent.  You can also try a spot removing the product.
 *  Fruit: Try to remove the stain before it dries by rinsing it in cold water. Otherwise, soak white garments in a chlorinated bleach solution.  For colored garments, treat with sodium percarbonate or warm borax solution.
 * Ink: Place a paper towel under the stain and then spray the stain with hairspray. Hairspray breaks up many types of ink, and you will want the paper towel there to catch the ink and not allow it to stain another part of the garment.  Hairspray may discolor the fabric though, so test in an inconspicuous place first.
 * Rust: Sprinkle the stain with salt and rub it in.  Then wet it with lemon juice and place it in the sun.  Keep the stain moistened with lemon juice until the stain disappears.
 * Grape juice: Mix one tablespoon of white vinegar and 1/2 teaspoon of liquid laundry detergent with one quart of warm water. Soak in this solution for 15 minutes. 4. If the stain remains, sponge with rubbing alcohol and rinse thoroughly.Apr 6, 2007

Why must stains be removed before laundering? == Putting a stained garment in a dryer will set the stain, making it even more difficult to remove. Always remove stains before laundering.

7. How are woolen and wool-like garments laundered?
Soak the garment in cold water for about 15 minutes. You can use shampoo instead of detergent, or you can use detergent specially formulated for wool. You can then change the water and soak the garment in clean water for another 15 minutes, or you can put it in a washing machine. If you decide to put it in a washing machine, make sure to select a setting that will not agitate the load. Also, be sure to use cold water.

Do not wring the wool out, and do not hang it up to dry. You can roll it in a dry towel, or just lay it flat to dry, but be careful not to stretch the fabric while it is wet, or it may become misshapen.

8. Why is it important to remove garments from a dryer immediately when the cycle is complete?
When a garment is still hot from the dryer, hanging it immediately will prevent it from getting wrinkled. If you forget to remove the garments from the dryer wrinkles will start to set, try throwing a damp washcloth into the dryer with the clothing and run the dryer for a few minutes. This may reduce the wrinkling.

9. What points are to be considered in selecting a washing machine, dryer, and iron? How should these items be cared for?
The primary concern when selecting a washing machine or a dryer is financial. Remember that the initial cost of the appliance is only a part of its operating cost though. Buying an energy-efficient appliance - even if it is more expensive - can save you a lot of money in the long run.

Another factor to consider is the amount of laundry you intend to do with the appliances. If you are going to do laundry for a family of six, you will need a larger machine than if you are going to do laundry for a family of two.

When selecting an iron, look for features that enhance safety. Many irons today will shut themselves off automatically if left idling for too long.

Wipe down your appliances regularly, and use appliance touch-up paint to repair any chips in the finish. An untreated chip will lead to rust which can destroy your appliance. Also be sure to clean out the lint trap of your dryer between every load, and clean the exhaust duct regularly. Lint build-up in the exhaust duct is a fire hazard.

Do not iron over silkscreen designs, as this will melt the paint on the garment and stick to the iron. This residue is extremely difficult to remove from an iron, and if left there, will transfer to any other garments you use it on.

10. Know what type of materials should be dried only on the lowest heat setting of a dryer.
Some items should not be dried in a dryer at all. Particularly, any item containing foam rubber should not be placed in a dryer except on a no-heat setting, as it can easily burst into flame.

Knits and delicates (such as silk and nylon) should only be dried on the lowest heat settings.

11. Show a blouse or shirt that you have properly ironed.
The most obvious garment to show is your class is a uniform. This requirement can be met before a club inspection or on a campout (assuming the uniform has been washed by the Pathfinder ahead of time).

12. Properly launder and fold clothes for your family for one week.
The regular launderer in your family will thank you for this. Make sure you tell that person "You're welcome!"


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PHP and MySQL Programming/Command Line Programming

PHP was traditionally used to help web administrators automate various mundane tasks and to add dynamism to the web pages. However, PHP (in its modern incarnation) is capable of much more. It is now being used in ways traditional programming languages are used. It is now possible to remove PHP applications from the constraints of the Internet server. Now, PHP is being used to write GUI applications as well as command line applications. We shall now look at writing PHP applications for the command line.

Getting the PHP-CLI
If you are running Linux, you should get the corresponding package for the PHP-CLI. In Debian, it is just a matter of typing:

In Windows, the CLI should be included with the PHP files. Refer to http://www.php-cli.com/ and http://www.php.net for more help.

Initial Considerations
We start off our command line applications with the following line:

Note: You do not include this line in Windows!

This should be the first line of the file, as it tells Linux which interpreter to use for the file.

The next thing you should do, is to make the file executable. This is done by the following Unix command:

Getting Keyboard Input
In order for us to retrieve keyboard input from the command line, we will need to use a little trick. Basically, we create a file handler to a special file called the Standard Input.

Here is the code to create this file handler:

We can now use $stdin just as if it were a normal file that we had opened for reading. (We obviously could not write to it, as it is Standard INPUT).

Here is a useful function to get user input:

Output Formatting
The main consideration to make when formatting output in command line programming as opposed to generating HTML output is that a new line is not created by a   tag, in fact, any HTML tags you put into the output, will simply be displayed as plain text.

In order to create a new line in the command line, we need to use a control character, \n. Another useful function when doing command line programming is this:

External Resources and Links
PHP CLI - ALL about running PHP script from command line: tutorials, options, examples, PHP CLI and PHP CGI difference.


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User:HolgiDE

HolgiDE

title: User:HolgiDE


text:
User:Dstudent~enwikibooks

Dstudent's user page is w:User:Dstudent.

title: User:Dstudent~enwikibooks


text:
World Stamp Catalogue/Europe

List of stamp-issuing entities in Europe

 * Albania - ALB
 * Andorra (French Post offices) - AND
 * Andorra (Spanish Post offices)
 * Armenia - ARM
 * Austria - AUT
 * UN Vienna Office
 * Belarus - BLR
 * Belgium - BEL
 * Bosnia and Herzegovina - BIH
 * Bulgaria - BGR
 * Croatia - HRV
 * Cyprus - CYP
 * Turkish Republic of Northern Cyprus
 * Czech Republic - CZE
 * Czechoslovakia - CSK
 * Denmark - DNK
 * Faroe Islands - FRO
 * Greenland - GRL
 * Estonia - EST
 * Finland - FIN
 * Åland Islands - ALA
 * France - FRA
 * Georgia - GEO
 * Germany - DEU
 * East Germany - DDR
 * Greece - GRC
 * Hungary - HUN
 * Iceland - ISL
 * Ireland - IRL
 * Italy - ITA
 * Latvia - LVA
 * Liechtenstein - LIE
 * Lithuania - LTU
 * Luxembourg - LUX
 * Republic of Macedonia - MKD
 * Malta - MLT
 * Republic of Moldova - MDA
 * Monaco - MCO
 * The Netherlands - NLD
 * Norway - NOR
 * Poland - POL
 * Portugal - PRT
 * Madeira
 * Azores
 * Romania - ROU
 * Russia - RUS
 * San Marino - SMR
 * Yugoslav Federation - YUG
 * Montenegro - MNE
 * Serbia - SRB
 * Slovakia - SVK
 * Slovenia - SVN
 * Soviet Union - SUN
 * Spain - ESP
 * Sweden - SWE
 * Switzerland - CHE
 * Basel
 * Bern
 * Fribourg
 * Geneva
 * Lucerne
 * Neuchâtel
 * Valais
 * International Olympic Committee
 * International Refugee Organization
 * World Intellectual Property Organization
 * Ukraine - UKR
 * Great Britain - GBR
 * Guernsey - GGY
 * Alderney
 * Gibraltar - GIB
 * Isle of Man - IMN
 * Jersey - JEY
 * Vatican City - VAT

title: World Stamp Catalogue/Europe


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Engineering Acoustics/Filter Design Outline

NOTE: The wikibook page will not necessarily follow this format. This is just a preliminary outline to get the project started.

INTRODUCTION:

1 - What Are They

2 - Examples

BASIC WAVE THEORY:

1 - Background

2 - Assumptions

BASIC FILTER DESIGN:

1 - Low Pass

2 - High Pass

3 - Bandpass

ACTUAL FILTER DESIGN:

1 - Problems

2 - Examples (refer to muffler page)

3 - Absorptive vs. Reactive mufflers

4 - Performance

BRIEF REVIEW of web sites for those interested in acoustic filters, links to other pages with relative information

CONCLUSION

Back to Acoustic Filter Design & Implementation


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Engineering Acoustics/Forced Oscillations(Simple Spring-Mass System)

Recap of Section 1.3
In the previous section, we discussed how adding a damping component (e. g. a dashpot) to an unforced, simple spring-mass system would affect the response of the system. In particular, we learned that adding the dashpot to the system changed the natural frequency of the system from  to a new damped natural frequency, and how this change made the response of the system change from a constant sinusoidal response to an exponentially-decaying sinusoid in which the system either had an under-damped, over-damped, or critically-damped response.

In this section, we will digress a bit by going back to the simple (undamped) oscillator system of the previous section, but this time, a constant force will be applied to this system, and we will investigate this system’s performance at low and high frequencies as well as at resonance. In particular, this section will start by introducing the characteristics of the spring and mass elements of a spring-mass system, introduce electrical analogs for both the spring and mass elements, learn how these elements combine to form the mechanical impedance system, and reveal how the impedance can describe the mechanical system’s overall response characteristics. Next, power dissipation of the forced, simple spring-mass system will be discussed in order to corroborate our use of electrical circuit analogs for the forced, simple spring-mass system. Finally, the characteristic responses of this system will be discussed, and a parameter called the amplification ratio (AR) will be introduced that will help in plotting the resonance of the forced, simple spring-mass system.

Forced Spring Element
Taking note of Figs. 1, we see that the equation of motion for a spring that has some constant, external force being exerted on it is...

$$\hat{F} = s_M \Delta \hat{x}\qquad (1.4.1) \,$$

where $$ s_M \,$$ is the mechanical stiffness of the spring.

Note that in Fig. 1(c), force $$\hat{F}$$ flows constantly (i.e. without decreasing) throughout a spring, but the velocity $$\hat{u}$$ of the spring decrease from $$\hat{u_1}$$ to $$\hat{u_2}$$ as the force flows through the spring. This concept is important to know because it will be used in subsequent sections.

In practice, the stiffness of the spring $$ s_M \,$$, also called the spring constant, is usually expressed as $$ C_M = \frac {1}{s_M}\, $$, or the mechanical compliance of the spring. Therefore, the spring is very stiff if $$ s_M \,$$ is large $$ \Rightarrow \; C_M $$ is small. Similarly, the spring is very loose or “bouncy” if $$ s_M \,$$ is small $$ \Rightarrow \; C_M $$  is large. Noting that force and velocity are analogous to voltage and current, respectively, in electrical systems, it turns out that the characteristics of a spring are analogous to the characteristics of a capacitor in relation to, and, so we can model the “reactiveness” of a spring similar to the reactance of a capacitor if we let $$ C = C_M \,$$ as shown in Fig. 2 below.

$$ Reactance\ of\ Capacitor:\ X_C = \frac{1}{j\omega C} \qquad (1.4.2a) $$

$$ Reactance\ of\ Spring:\ X_{MS} = \frac{1}{j\omega C_M} \qquad(1.4.2b) $$

Forced Mass Element
Taking note of Fig. 3, the equation for a mass that has constant, external force being exerted on it is...

$$ \hat{F} = M_M \hat{a} = M_M \hat{\dot{u}} = M_M \hat{\ddot{x}} \qquad (1.4.3)   $$

If the mass $$ M_M \, $$ can vary its value and is oscillating in a mechanical system at max amplitude $$ A_M \, $$ such that the input the system receives is constant at frequency $$ \omega \, $$, as $$ M_M \, $$ increases, the harder it will be for the system to move the mass at $$ \omega \, $$  at $$ A_M \, $$  until, eventually, the mass doesn’t oscillate at all. Another equivalently way to look at it is to let $$ \omega \, $$ vary and hold $$ M_M \, $$ constant. Similarly, as $$ \omega \, $$ increases, the harder it will be to get $$ M_M \, $$ to oscillate at $$ \omega \, $$  and keep the same amplitude $$ A_M \, $$  until, eventually, the mass doesn’t oscillate at all. Therefore, as $$ \omega \, $$ increases, the “reactiveness” of mass $$ M_M \, $$ decreases (i.e. $$ M_M \, $$  starts to move less and less). Recalling the analogous relationship of force/voltage and velocity/current, it turns out that the characteristics of a mass are analogous to an inductor. Therefore, we can model the “reactiveness” of a mass similar to the reactance of an inductor if we let $$ L = M_M \, $$ as shown in Fig. 4.

$$ Reactance\ of\ Inductor:\ X_L = j\omega L \qquad (1.4.4a) $$

$$ Reactance\ of\ Mass:\ X_{MM} = j\omega L_M \qquad(1.4.4b) $$

Mechanical Impedance of Spring-Mass System
As mentioned twice before, force is analogous to voltage and velocity is analogous to current. Because of these relationships, this implies that the mechanical impedance for the forced, simple spring-mass system can be expressed as follows:

$$ \hat{Z_M} = \frac{\hat{F}}{\hat{u}} \qquad (1.4.5) \,$$

In general, an undamped, spring-mass system can either be “spring-like” or “mass-like”. “Spring-like” systems can be characterized as being “bouncy” and they tend to grossly overshoot their target operating level(s) when an input is introduced to the system. These type of systems relatively take a long time to reach steady-state status. Conversely, “mass-like” can be characterized as being “lethargic” and they tend to not reach their desired operating level(s) for a given input to the system...even at steady-state! In terms of complex force and velocity, we say that “ force LEADS velocity” in mass-like systems and “velocity LEADS force” in spring-like systems (or equivalently “ force LAGS velocity” in mass-like systems and “velocity LAGS force” in spring-like systems). Figs. 5 shows this relationship graphically.

Power Transfer of a Simple Spring-Mass System
From electrical circuit theory, the average complex power $$ P_E \,$$ dissipated in a system is expressed as ...

$$ P_E = \frac{1}{2} \mathbf{Re}\left\{ \hat{V}\hat{I^*} \right\} \qquad (1.4.6)\,$$

where $$ \hat{V}\,$$ and $$ \hat{I^*}\;$$ represent the (time-invariant) complex voltage and complex conjugate current, respectively. Analogously, we can express the net power dissipation of the mechanical system $$ \hat{P}_E\,$$ in general along with the power dissipation of a spring-like system $$ \hat{P}_{MS}\,$$ or mass-like system $$\hat{P}_{MM}\,$$ as...

$$ \hat{P}_E = \frac{1}{2} \mathbf{Re}\left\{ \hat{F}\hat{u^*} \right\} \qquad \qquad \qquad (1.4.7a)\,$$

$$ \hat{P}_{MS} = \frac{1}{2} \mathbf{Re}\left\{\hat{F} \left( \frac{j\hat{F}\omega}{s_M} \right)^* \right\} \qquad (1.4.7b) $$

$$ \hat{P}_{MM} = \frac{1}{2} \mathbf{Re}\left\{\hat{F} \left( \frac{\hat{F}}{j \omega M_M} \right)^* \right\} \qquad (1.4.7c) $$

In equations 1.4.7, we see that the product of complex force and velocity are purely imaginary. Since reactive elements, or commonly called, lossless elements, cannot dissipate energy, this implies that the net power dissipation of the system is zero. This means that in our simple spring-mass system, power can only be (fully) transferred back and forth between the spring and the mass. But this is precisely what a simple spring-mass system does. Therefore, by evaluating the power dissipation, this corroborates the notion of using electrical circuit elements to model mechanical elements in our spring-mass system.

Responses For Forced, Simple Spring-Mass System
Fig. 6 below illustrates a simple spring-mass system with a force exerted on the mass.

This system has response characteristics similar to that of the undamped oscillator system, with the only difference being that at steady-state, the system oscillates at the constant force magnitude and frequency versus exponentially decaying to zero in the unforced case. Recalling equations 1.4.2b and 1.4.4b, letting  be the natural (resonant) frequency of the spring-mass system, and letting $$ \omega_n \,$$ be frequency of the input received by the system, the characteristic responses of the forced spring-mass systems are presented graphically in Figs. 7 below.

$$ \mathbf{Figs.7}\,$$

Amplification Ratio
The amplification ratio is a useful parameter that allows us to plot the frequency of the spring-mass system with the purports of revealing the resonant freq of the system solely based on the force experienced by each, the spring and mass elements of the system. In particular, AR is the magnitude of the ratio of the complex force experienced by the spring and the complex force experienced by the mass, i.e.

$$ \mathbf{AR} = \left| \frac{s_M \hat{x}}{M_M \hat{a}} \right| = \left| \frac{s_M \hat{x}}{M_M \hat{\dot{u}}} \right| = \left| \frac{s_M \hat{x}}{M_M \hat{\ddot{x}}} \right| \qquad (1.4.8) \,$$

If we let $$ \zeta = \frac{\omega}{\omega_n} $$, be the frequency ratio, it turns out that AR can also be expressed as...

$$ \mathbf{AR} = \frac{1}{1 - \zeta^2} \qquad (1.4.9)\,$$.

AR will be at its maximum when $$ \left| X_{MS} \right| = \left| X_{MM} \right| \,$$. This happens precisely when $$ \zeta^2 = 1 \,$$. An example of an AR plot is shown below in Fig 8.

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Engineering Acoustics/Flow-induced oscillations of a Helmholtz resonator and applications

Introduction
The importance of flow excited acoustic resonance lies in the large number of applications in which it occurs. Sound production in organ pipes, compressors, transonic wind tunnels, and open sunroofs are only a few examples of the many applications in which flow excited resonance of Helmholtz resonators can be found.[4] An instability of the fluid motion coupled with an acoustic resonance of the cavity produce large pressure fluctuations that are felt as increased sound pressure levels. Passengers of road vehicles with open sunroofs often experience discomfort, fatigue, and dizziness from self-sustained oscillations inside the car cabin. This phenomenon is caused by the coupling of acoustic and hydrodynamic flow inside a cavity which creates strong pressure oscillations in the passenger compartment in the 10 to 50 Hz frequency range. Some effects experienced by vehicles with open sunroofs when buffeting include: dizziness, temporary hearing reduction, discomfort, driver fatigue, and in extreme cases nausea. The importance of reducing interior noise levels inside the car cabin relies primarily in reducing driver fatigue and improving sound transmission from entertainment and communication devices. This Wikibook page aims to theoretically and graphically explain the mechanisms involved in the flow-excited acoustic resonance of Helmholtz resonators. The interaction between fluid motion and acoustic resonance will be explained to provide a thorough explanation of the behavior of self-oscillatory Helmholtz resonator systems. As an application example, a description of the mechanisms involved in sunroof buffeting phenomena will be developed at the end of the page.

=Feedback loop analysis= As mentioned before, the self-sustained oscillations of a Helmholtz resonator in many cases is a continuous interaction of hydrodynamic and acoustic mechanisms. In the frequency domain, the flow excitation and the acoustic behavior can be represented as transfer functions. The flow can be decomposed into two volume velocities.

qr: flow associated with acoustic response of cavity

qo: flow associated with excitation

Figure 1 shows the feedback loop of these two volume velocities.

Figure 1

=Acoustical characteristics of the resonator=

Lumped parameter model
The lumped parameter model of a Helmholtz resonator consists of a rigid-walled volume open to the environment through a small opening at one end. The dimensions of the resonator in this model are much less than the acoustic wavelength, in this way allowing us to model the system as a lumped system.

where re is the equivalent radius of the orifice.

Figure 2 shows a sketch of a Helmholtz resonator on the left, the mechanical analog on the middle section, and the electric-circuit analog on the right hand side. As shown in the Helmholtz resonator drawing, the air mass flowing through an inflow of volume velocity includes the mass inside the neck (Mo) and an end-correction mass (Mend). Viscous losses at the edges of the neck length are included as well as the radiation resistance of the tube. The electric-circuit analog shows the resonator modeled as a forced harmonic oscillator. [1] [2][3]

Figure 2

V: cavity volume

$$\rho$$: ambient density

c: speed of sound

S: cross-section area of orifice

K: stiffness

$$M_a$$: acoustic mass

$$C_a$$: acoustic compliance

The equivalent stiffness K is related to the potential energy of the flow compressed inside the cavity. For a rigid wall cavity it is approximately:

$$ K = \left(\frac{\rho c^2}{V}\right)S^2 $$

The equation that describes the Helmholtz resonator is the following:

$$ S \hat{P}_e =\frac{\hat{q}_e}{j\omega S}(-\omega ^2 M + j\omega R + K) $$

$$\hat{P}_e$$: excitation pressure

M: total mass (mass inside neck Mo plus end correction, Mend)

R: total resistance (radiation loss plus viscous loss)

From the electrical-circuit we know the following:

$$ M_a = \frac{L \rho}{S} $$

$$ C_a = \frac{\pi V}{\rho c^2} $$

$$ L ' = \ L + \ 1.7 \ re $$

The main cavity resonance parameters are resonance frequency and quality factor which can be estimated using the parameters explained above (assuming free field radiation, no viscous losses and leaks, and negligible wall compliance effects)

$$ \omega_r^2 = \frac{1}{M_a C_a} $$

$$ f_r = c 2 \pi \sqrt{\frac{S}{L' V}} $$

The sharpness of the resonance peak is measured by the quality factor Q of the Helmholtz resonator as follows:

$$ Q = 2 \pi \sqrt{V \left(\frac{L'} {S}\right)^3} $$

$$ f_r$$: resonance frequency in Hz

$$\omega_r$$: resonance frequency in radians

L: length of neck

L': corrected length of neck

From the equations above, the following can be deduced:

-The greater the volume of the resonator, the lower the resonance frequencies. -If the length of the neck is increased, the resonance frequency decreases.

Production of self-sustained oscillations
The acoustic field interacts with the unstable hydrodynamic flow above the open section of the cavity, where the grazing flow is continuous. The flow in this section separates from the wall at a point where the acoustic and hydrodynamic flows are strongly coupled. [5]

The separation of the boundary layer at the leading edge of the cavity (front part of opening from incoming flow) produces strong vortices in the main stream. As observed in Figure 3, a shear layer crosses the cavity orifice and vortices start to form due to instabilities in the layer at the leading edge.

Figure 3

From Figure 3, L is the length of the inner cavity region, d denotes the diameter or length of the cavity length, D represents the height of the cavity, and $$\delta$$ describes the gradient length in the grazing velocity profile (boundary layer thickness).

The velocity in this region is characterized to be unsteady and the perturbations in this region will lead to self-sustained oscillations inside the cavity. Vortices will continually form in the opening region due to the instability of the shear layer at the leading edge of the opening.

=Applications to Sunroof Buffeting=

How are vortices formed during buffeting?
In order to understand the generation and convection of vortices from the shear layer along the sunroof opening, the animation below has been developed. At a certain range of flow velocities, self-sustained oscillations inside the open cavity (sunroof) will be predominant. During this period of time, vortices are shed at the trailing edge of the opening and continue to be convected along the length of the cavity opening as pressure inside the cabin decreases and increases. Flow visualization experimentation is one method that helps obtain a qualitative understanding of vortex formation and conduction.

The animation below, shows in the middle, a side view of a car cabin with the sunroof open. As the air starts to flow at a certain mean velocity Uo, air mass will enter and leave the cabin as the pressure decreases and increases again. At the right hand side of the animation, a legend shows a range of colors to determine the pressure magnitude inside the car cabin. At the top of the animation, a plot of circulation and acoustic cavity pressure versus time for one period of oscillation is shown. The symbol x moving along the acoustic cavity pressure plot is synchronized with pressure fluctuations inside the car cabin and with the legend on the right. For example, whenever the x symbol is located at the point where t=0 (when the acoustic cavity pressure is minimum) the color of the car cabin will match that of the minimum pressure in the legend (blue).

The perturbations in the shear layer propagate with a velocity of the order of 1/2Uo which is half the mean inflow velocity. [5] After the pressure inside the cavity reaches a minimum (blue color) the air mass position in the neck of the cavity reaches its maximum outward position. At this point, a vortex is shed at the leading edge of the sunroof opening (front part of sunroof in the direction of inflow velocity). As the pressure inside the cavity increases (progressively to red color) and the air mass at the cavity entrance is moved inwards, the vortex is displaced into the neck of the cavity. The maximum downward displacement of the vortex is achieved when the pressure inside the cabin is also maximum and the air mass in the neck of the Helmholtz resonator (sunroof opening) reaches its maximum downward displacement. For the rest of the remaining half cycle, the pressure cavity falls and the air below the neck of the resonator is moved upwards. The vortex continues displacing towards the downstream edge of the sunroof where it is convected upwards and outside the neck of the resonator. At this point the air below the neck reaches its maximum upwards displacement.[4] And the process starts once again.

How to identify buffeting
Flow induced tests performed over a range of flow velocities are helpful to determine the change in sound pressure levels (SPL) inside the car cabin as inflow velocity is increased. The following animation shows typical auto spectra results from a car cabin with the sunroof open at various inflow velocities. At the top right hand corner of the animation, it is possible to see the inflow velocity and resonance frequency corresponding to the plot shown at that instant of time.

It is observed in the animation that the SPL increases gradually with increasing inflow velocity. Initially, the levels are below 80 dB and no major peaks are observed. As velocity is increased, the SPL increases throughout the frequency range until a definite peak is observed around a 100 Hz and 120 dB of amplitude. This is the resonance frequency of the cavity at which buffeting occurs. As it is observed in the animation, as velocity is further increased, the peak decreases and disappears. In this way, sound pressure level plots versus frequency are helpful in determining increased sound pressure levels inside the car cabin to find ways to minimize them. Some of the methods used to minimize the increased SPL levels achieved by buffeting include: notched deflectors, mass injection, and spoilers.

=Useful Websites=

This link: takes you to the website of EXA Corporation, a developer of PowerFlow for Computational Fluid Dynamics (CFD) analysis.

This link: is a small news article about the current use of(CFD) software to model sunroof buffeting.

This link: is a small industry brochure that shows the current use of CFD for sunroof buffeting.

=References= [1] Acoustics: An introduction to its Physical Principles and Applications ; Pierce, Allan D., Acoustical Society of America, 1989.

[2] Prediction and Control of the Interior Pressure Fluctuations in a Flow-excited Helmholtz resonator ; Mongeau, Luc, and Hyungseok Kook., Ray W. Herrick Laboratories, Purdue University, 1997.

[3]Influence of leakage on the flow-induced response of vehicles with open sunroofs ; Mongeau, Luc, and Jin-Seok Hong., Ray W. Herrick Laboratories, Purdue University.

[4]Fluid dynamics of a flow excited resonance, part I: Experiment ; P.A. Nelson, Halliwell and Doak.; 1991.

[5]An Introduction to Acoustics ; Rienstra, S.W., A. Hirschberg., Report IWDE 99-02, Eindhoven University of Technology, 1999.

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