Sunday, November 30, 2008

A Sonic boom

A Sonic Boom
From Wikipedia, the free encyclopedia

The term sonic boom is commonly used to refer to the shocks caused by the supersonic flight of an aircraft.

Sonic booms generate enormous amounts of sound energy, sounding much like an explosion. Thunder is a type of natural sonic boom, created by the rapid heating and expansion of air in a lightning discharge


When an object passes through the air, it creates a series of pressure waves in front of it and behind it, similar to the bow and stern waves created by a boat.

These waves travel at the speed of sound, and as the speed of the object increases, the waves are forced together, or compressed, because they cannot "get out of the way" of each other, eventually merging into a single shock wave at the speed of sound. This critical speed is known as Mach 1 and is approximately 1,225 kilometers per hour (761 mph) at sea level.

In smooth flight, the shock wave starts at the nose of the aircraft and ends at the tail. Because directions around the aircraft's direction of travel are equivalent, the shock forms a cone with the aircraft at its tip. The half-angle (between direction of flight and the shock wave ) A is given by sin(A) = 1/M, where M is the plane's Mach number.

So the faster it goes, the finer, more pointed the cone. There is a sudden rise in pressure at the nose, decreasing steadily to a negative pressure at the tail, followed by a sudden return to normal pressure after the object passes. This "overpressure profile" is known as an N-wave because of its shape.

The "boom" is experienced when there is a sudden change in pressure, so the N-wave causes two booms, one when the initial pressure rise from the nose hits, and another when the tail passes and the pressure suddenly returns to normal.

This leads to a distinctive "double boom" from supersonic aircraft. When maneuvering, the pressure distribution changes into different forms, with a characteristic U-wave shape.

Since the boom is being generated continually as long as the aircraft is supersonic, it fills out a narrow path on the ground following the aircraft's flight path, a bit like an unrolling celebrity carpet and hence known as the boom carpet.

Its width depends an the altitude of the aircraft. The distance of the point on the ground where the boom is heard to the aircraft depends on its altitude and the angle A.


The power, or volume, of the shock wave is dependent on the quantity of air that is being accelerated, and thus the size and shape of the aircraft. As the aircraft increases speed the shocks grow "tighter" around the craft and do not become much "louder".

At very high speeds and altitudes the cone does not intersect the ground and no boom is heard. The "length" of the boom from front to back is dependent on the length of the aircraft to a factor of 3:2[citation needed]. Longer aircraft therefore "spread out" their booms more than smaller ones, which leads to a less powerful boom which has a less "spread out" boom.

Several smaller shock waves can, and usually do, form at other points on the aircraft, primarily any convex points or curves, the leading wing edge and especially the inlet to engines. These secondary shockwaves are caused by the air being forced to turn around these convex points, which generates a shock wave in supersonic flow.

The later shock waves are somehow faster than the first one, travel faster and add to the main shockwave at some distance away from the aircraft to create a much more defined N-wave shape. This maximizes both the magnitude and the "rise time" of the shock which makes the boom seem louder.

On most designs the characteristic distance is about 40,000 feet (12,000 m), meaning that below this altitude the sonic boom will be "softer". However, the drag at this altitude or below makes supersonic travel particularly inefficient, which poses a serious problem.


In the late 1950s when supersonic transport (SST) designs were being actively pursued, it was thought that although the boom would be very large, the problems could be avoided by flying higher.

This premise was proven false when the North American B-70 Valkyrie started flying, and it was found that the boom was a problem even at 70,000 feet (21,000m). It was during these tests that the N-wave was first characterized.

Richard Seebass and his colleague Albert George at Cornell University studied the problem extensively and eventually defined a "figure of merit" (FM) to characterize the sonic boom levels of different aircraft. FM is a function of the aircraft weight and the aircraft length.

The lower this value, the less boom the aircraft generates, with figures of about 1 or lower being considered acceptable. Using this calculation, they found FM's of about 1.4 for Concorde and 1.9 for the Boeing 2707. This eventually doomed most SST projects as public resentment mixed with politics eventually resulted in laws that made any such aircraft impractical (flying only over water for instance).

Another way to express this is wing span. The fuselage of even large supersonic aeroplanes is very sleek and with enough angle of attack and wing span the plane can fly so high that the boom by the fuselage is not important.

The larger the wing span, the greater the downwards impulse which can be applied to the air, the greater the boom felt. A smaller wing span favors small aeroplane designs like business jets. Seebass-George also worked on the problem from another angle, trying to spread out the N-wave laterally and temporally (longitudinally), by producing a strong and downwards-focused (SR-71 Blackbird, Boeing X-43) shock at a sharp, but wide angle nosecone, which will travel at slightly supersonic speed (bow shock), and using a swept back flying wing or an oblique flying wing to smooth out this shock along the direction of flight (the tail of the shock travels at sonic speed).

To adapt this principle to existing planes, which generate a shock at their nose-cone and an even stronger one at their wing leading edge, the fuselage below the wing is shaped according to the area rule. Ideally this would raise the characteristic altitude from 40,000 feet to 60,000 feet (from 12,000 m to 18,000 m), which is where most SST aircraft fly.

This remained untested for decades, until DARPA started the Quiet Supersonic Platform project and funded the Shaped Sonic Boom Demonstration (SSBD) aircraft to test it. SSBD used an F-5 Freedom Fighter. The F-5E was modified with a highly refined shape which lengthened the nose to that of the F-5F model.

The fairing extended from the nose all the way back to the inlets on the underside of the aircraft. The SSBD was tested over a two year period culminating in 21 flights and was an extensive study on sonic boom characteristics.

After measuring the 1,300 recordings, some taken inside the shock wave by a chase plane, the SSBD demonstrated a reduction in boom by about one-third. Although one-third is not a huge reduction, it could have reduced Concorde below the FM = 1 limit for instance.

As a follow-on to SSBD, in 2006 a NASA-Gulfstream Aerospace team tested the Quiet Spike on NASA-Dryden's F-15B aircraft 836. The Quiet Spike is a telescoping boom fitted to the nose of an aircraft specifically designed to weaken the strength of the shock waves forming on the nose of the aircraft at supersonic speeds.

Over 50 test flights were performed. Several flights included probing of the shockwaves by a second F-15B, NASA's Intelligent Flight Control System testbed, aircraft 837.

There are theoretical designs that do not appear to create sonic booms at all, such as the Busemann's Biplane

Perception and noise

The sound of a sonic boom depends largely on the distance between the observer and the aircraft shape producing the sonic boom. A sonic boom is usually heard as a deep double "boom" as the aircraft is usually some distance away.

However, as those who have witnessed landings of space shuttles have heard, when the aircraft is nearby the sonic boom is a sharper "bang" or "crack". The sound is much like the "aerial bombs" used at firework displays.

In 1964, NASA and the Federal Aviation Administration began the Oklahoma City sonic boom tests, which caused eight sonic booms per day over a period of six months. Valuable data was gathered from the experiment, but 15,000 complaints were generated and ultimately entangled the government in a class action lawsuit, which it lost on appeal in 1969.

There has been recent work in this area, notably under DARPA's Quiet Supersonic Platform studies. Research by acoustics experts under this program began looking more closely at the composition of sonic booms, including the frequency content.

Several characteristics of the traditional sonic boom "N" wave can influence how loud and irritating it can be perceived by listeners on the ground. Even strong N-waves such as those generated by Concorde or military aircraft can be far less objectionable if the rise time of the overpressure is sufficiently long.

A new metric has emerged, known as perceived loudness, measured in PLdB. This takes into account the frequency content, rise time, etc. A well known example is the snapping of your fingers in which the "perceived" sound is nothing more than an annoyance.

The composition of the atmosphere is also a factor. Temperature variations, humidity, pollution, and winds can all have an effect on how a sonic boom is perceived on the ground. Even the ground itself can influence the sound of a sonic boom.

Hard surfaces such as concrete, pavement, and large buildings can cause reflections which may amplify the sound of a sonic boom. Similarly grassy fields and lots of foliage can help attenuate the strength of the overpressure of a sonic boom.

Currently there are no industry accepted standards for the acceptability of a sonic boom. Until such metrics can be established, either through further study or supersonic overflight testing, it is doubtful that legislation will be enacted to remove the current prohibition on supersonic overflight in place in several countries, including the United States.


The cracking sound a bullwhip makes when properly wielded is, in fact, a small sonic boom. The end of the whip, known as the "cracker", moves faster than the speed of sound, thus resulting in the sonic boom. The whip was the first human invention to break the sound barrier.

A bullwhip tapers down from the handle section to the cracker. The cracker has much less mass than the handle section. When the whip is sharply swung, the energy is transferred down the length of the tapering whip.

In accordance with the formula for kinetic energy (Ek = mv2 / 2), the velocity of the whip increases with the decrease in mass, which is how the whip reaches the speed of sound and causes a sonic boom.

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Wednesday, November 26, 2008

Engineering Careers: Analysis And Creativity Come Together

Engineering Careers: Analysis And Creativity Come Together

At the other end of the spectrum, however, lies a more optimistic breed. These people believe that the world as we know it does not live up to its potential.

They are highly inquisitive, and dare to challenge the status quo. If you count yourself among this league of imaginative dreamers--and possess the mathematical and scientific training necessary to execute your visions--the field of engineering could prove a highly rewarding career path.

Engineers not only enjoy the satisfaction of making the world a better place, but also boast some of the highest starting salaries of all college graduates.

Engineering: A Basic Job Description
Engineers act as liaisons between the world of pure research and its commercial applications.

Drawing on their formal education and their fluency in modern technology, engineers design, test, and evaluate new products.

They rely heavily on computers for both product development and procedural monitoring. An engineer's career choices are incredibly varied, ranging from biotechnology to electronics development, and nearly everything in between.

In fact, the Bureau of Labor Statistics (BLS) recognizes 17 major engineering specialties.

Educational Requirements for Engineers
Most engineers enter the field with a bachelor's degree. Students may find the engineering program of study to be refreshingly well rounded, covering the expected subjects of mathematics and physical & life sciences, but also including courses in design, the social sciences, and humanities.

Because most engineers specialize, undergraduate engineering students typically concentrate on a specific area of study.

The BLS notes, moreover, that prospective students should carefully investigate a school's curriculum before graduating.

A program's content can vary widely from one institution to the next, and aspiring engineers may want to ensure that their education aligns with their future career path.

Other Engineering Requirements
In addition to a bachelor's degree, successful engineers boast excellent communication and analytical skills. Creativity is also a must in this field of ever-expanding horizons.

An engineer's education is essentially never-ending. Once hired, engineers need to keep themselves abreast of new technological developments in order to remain valuable to their employers.

Job & Salary Outlook
Job openings for engineers should be plentiful in the coming decade, with faster-than-average growth projected for environmental and industrial engineering specialties.

Earnings vary considerably based on specialty and level of education. As of 2007, the average starting salary for an engineer with a bachelor's degree ranged from $47,960 (environmental engineers) to $60,718 (petroleum engineers).

Typical engineering programs take 4-5 years to complete, so don't hesitate to begin your college search and start pursuing this exciting career.

By: Kelli Smith

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Friday, November 21, 2008

3 Health Tips For Your Kids

3 Health Tips For Your Kids
By Sue Baker

The health of children is a major issue in the US and UK not only for each individual family but also for the governments.

More and more children are falling prey to bad eating habits and are suffering from childhood obesity.

What can be done to ensure that they don't end up developing a huge potbelly and protect their health?

Here are 3 health tips for your kids to help them avoid obesity problems in both childhood and when they become adults.

1. Start training them early:

Training your kids on how to lead a healthy life should start early. When they are very young teach them healthy eating and lifestyle habits.

Avoid putting sugary products on their soother or giving them sweet snacks and sugary drinks just for an easy life.

If you train them in good health right from an early age, they would be able to make health choices for themselves when they become older.

Some parents indulge their children with unhealthy foods when they are young and then can't understand why they won't eat fresh fruits and vegetables when they are older. Parents should encourage children to eat healthy foods right from the start!

2. Eat as a family:

A family which eats together stays healthy together. It is common practice nowadays for parents to eat separately or in front of the television set. It is far better to sit round the table as a family so that you can ensure that they are following the healthy eating habits that you have taught them.

Eating as a family has the added advantage of each person having the opportunity to discuss their day and for you to know if there are any problems to be addressed. Share all your ups and downs!

Children also learn about social skills required for when they grow up. It has been found in the UK that a number of children entering primary school for the first time do not even know how to use a knife and fork because they are so used to eating pizza or other finger foods in front of the TV. How sad is that?

3. Be a role model for your kids:

How can you expect your kids to follow your advice if you do not practice what you preach. Practice what you preach; your kids too will follow you! Children, especially very young children imitate their parents and copy what they do. If they see you following a healthy and perfect lifestyle they will more than likely, do the same.

Keep in mind that kids, even though younger in age than you, are not fools! They see and understand more than what you think. By walking the talk and living a healthy lifestyle yourself, you will not only serve as a role model for your kids, but also improve your own health condition!

Get them involved with meal planning, preparing the meal, and cooking it with close supervision and according to their age. Teach then well and let them make healthy choices for their own lunch boxes.

Even if your kids follow any unhealthy eating habit, you can rectify it early before it turns into a bad habit!

Follow these three easy tips to ensure that your kids have the knowledge to be able to start to live healthily throughout their entire life!

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Thursday, November 20, 2008

What is Obesity and How to Fight It

What is Obesity and How to Fight It
By Carrie S Donald

No one would say obesity is attractive, nor healthy. Prevention of obesity is really a straightforward proposition. If you'll forgive the pun, prevention of obesity is truly worth many pounds of cure.

People of normal, stable weight may gain a few pounds over the holidays, partaking of all that holiday cheer. Cookies, fudge, delicious gravies and a few glasses of eggnog are all it takes to get you there. However, most people shed those pounds within a couple of months, once they return to normal eating habits. It all comes down to a reduction of calories.

Prevention of obesity should become your target when you find you've gained ten pounds or more and it doesn't come off. An alarm should sound off in your head when weight starts creeping on and you seem unable to lose weight. Now is the time to take action! It's far easier to lose ten or twenty pounds than a hundred!

Other signals that indicate a prevention program is necessary include finding that your clothes are too snug. Many people have sections in their closet, one their 'fat' clothes, with another for their 'skinny' clothes. Not only is this an unnecessary expense, but a psychological trick you're playing on yourself. It goes something like this. "Well, I guess I just have to accept it - people do tend to gain weight as they get older. What's one dress size anyway? I still look OK."

The trouble with this attitude is that you're putting yourself in denial. This means you'll not be motivated to prevent obesity, because you don't think it's possible. You might make a token attempt to diet, but you won't stick with the program. This is how that weight eventually balloons to an unmanageable problem.

So, the real core issue in the prevention of obesity begins in your mind. You must be motivated. Do you want to wait until the day when some little child in the grocery tells her Mom, "Look how fat that woman is!"? That's when it's useless to deny the fact. Prevention of obesity involves an early start.

If you need help in getting motivated, here are a few tips. Go online and calculate your BMI. Read up on the many health problems you may well face. Heart disease, poor circulation, diabetes and joint stress damage are just a few. Dig through old photo albums to find pictures of you when you were of normal weight. Tape that photo on the frig, at eye level, along with a picture of you now. Try on one of your 'skinny' clothes.

OK. Now you've got the motivation. You should first check with your doctor to be sure you don't have a medical condition, like a thyroid imbalance. If that's not the case, get ready to diet. Don't cut yourself any slack. Remember, prevention of obesity is your goal.

Losing weight always boils down to calories. How do you know how many calories you normally eat? Keep a food journal for one week. Write down every last cracker and soda that passes your lips. Get a calorie counter book. Ask your doctor to help plan a diet that's healthy and right for you.

Motivation is the key to prevention of obesity. With a radical dose of motivation, you'll lose that extra weight for good

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Monday, November 10, 2008

Exercise For Asthma Patients - Some Important Tips

Exercise For Asthma Patients - Some Important Tips
By Abhishek Agarwal

Most people who suffer from Asthma perhaps wonder if they can exercise safely or properly. Leaving apart what most people think, one can actually exercise to get in shape even when you are a victim of Asthma.

Asthma comes more as a lung disorder that is chronic, marked by features of wheezing, shortness of breath, chest tightness and coughing. Asthma occurs when people get environmentally or genetically predisposed to conditions.

Triggers such as viral respiratory infections, exposure to cockroaches or dust mites and exposure to allergens could start or make any attack worse.

Preventing Asthma could be done in the following manner:

1. Make sure to bathe your pets at least weekly.

2. Never smoke or permit to smoke at your dwelling

3. When pollen or mold counts are more, ensure to stay in-door with air-conditioning.

4. Don't forget to wash stuffed toys and bedding at least once in a week with hot water.

5. Ensure to wash hands every time you get the chance.

6. Have a flu shot given to yourself.

7. During Winter wear a scarf covering nose and mouth.

8. Become proactive knowing your triggers right; knowing how to avoid them.

The above pointers have made you aware about asthma prevention. There are exercises that fit in such circumstances too. Any doctor would suggest not giving up on exercise and sports, whatsoever. All that people need to be aware of is to be alert and smart about taking special pre-cautions towards avoiding attacks.

Doctors would agree that preventing attacks while you are exercising could be done in a best way; using an inhaler along with appropriate medications. Inhalers should not be used more than three times when you are in an exercise session or a game. If you have been wheezing and coughing the previous night, then it is implied to implement lighter exercises the next day.

For Exercise Induced Asthma, IEA, the symptoms differ to what is generic. The attack occurs after about 6-7 minutes of attack and is often worse in case of dry and cold air.

When you are suffering from IEA, there are various activities which could be enjoyed. These activities include walking, biking, downhill skiing, swimming, or team based sports. Quite many activities could be tried to ascertain that you get the much needed exercise.

Asthma is not something that is within the mind; it is fully physiological and an equally similar medical treatment is required for the same. Your doctor is the best person who could assist you with the disorder; you need to prevent yourself from any asthma attacks.

Ascertain to be smart by taking the right medications at the right time and being proactive. Never let asthma bring misery in your life; enjoy life and exercise just like anyone else would have done

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Wednesday, November 5, 2008

Stress Solutions: Ten Tips To Cope With Stress

Stress Solutions: Ten Tips To Cope With Stress
By: Dr Arien van der Merwe

Stress levels are higher than ever. The current economic crisis is taking its toll on physical and mental health and wellbeing. All the distress obviously affects workplaces, and particularly morale and productivity. Short fuses dramatically increase the potential for dysfunctional behaviours that affect everyone from top management and colleagues, to customers and families. Managing stress is vital to overall health and wellbeing!

• One minute stress buster: Breathe in deeply through your nose on a slow count of three. Push your stomach out as you breathe in. Hold it for a count of three. Breathe out through your mouth on a slow count of six. Repeat two or more times. Try this every time you feel stressed, anxious or worried. Do it every morning before you get up and every night before falling asleep. Feel your pulse rate by putting your fingers gently on your wrist below the thumb. When you’re stressed, your breathing and pulse rate become fast. Do the slow breathing and feel how your pulse rate slows down – a quick fix stress buster!

• Quiet time and deep relaxation: Can be done anywhere, anytime to refocus the mind and improve concentration and sense of wellbeing. Deep relaxation enhances cardiovascular health, respiratory health, balances the endocrine and nervous system and improves mental clarity. Imagine your thoughts being the waves on the surface of the ocean. They go up and down as the mood, your feelings, emotions and your memory dictate. The deeper ocean is quiet, still and peaceful. This is the part you can access voluntarily any time of the day and night through meditation, visualisation, deep breathing and prayer.

Practice mindfulness

• On waking, spend a few moments lying in bed. Enjoy the delight of the fresh morning air, the sparkle of early sunlight, the sound of birds. Sense the life flowing through your body. Notice your breath, the pulsing of blood in your fingertips, the tug of gravity upon your arms, legs, and trunk. Take a few deep slow breaths. This is a good time to write in your journal – dreams, thoughts, ideas, feelings. Get out of bed slowly, observing the shift in your center of balance as you move into an upright position. Stand erect, without strain. Feel your feet on the ground. Become aware of your whole body. Go about the early morning’s activities with mindfulness, really experiencing them with all your senses. Cultivate serenity early in the morning and carry the feeling with you throughout the day. We control how we respond to irritations, worries, doubts and fears. Preparing the mind like this, calmly centers you throughout the day.

• Spend a few minutes every morning in quiet contemplation. Create your special space – upright in your bed, a meditation stool, or cushion, or a comfortable chair, crystals, colourful candles, soft music or the silence of a perfect day.

- You can eat, drink, or walk mindfully by focusing exclusively on eating, drinking, or walking.
- Stop and notice your breath at various times throughout the day.
- Cultivate a sense of being, rather than always feeling like you have to be doing something.

• Tired eye soother

Splash eyes with cold water – alternate with a hot washcloth over your closed eyelids and press gently with your fingertips. Rub an ice cube around each eyeLie back in your chair or on a bed, place sliced cucumber or a wet tea bag over your closed eyes and relax for a few minutesDo eye exercises: blink a few times, focus on objects far and then near you, move your eyes in a circle, keeping your head still, rub the palms of your hands vigorously together and place over your closed eyelids.

Support your body to help you cope with stress

• Have regular mini breaks every 2 hours from sitting or standing where your muscles remain in one position all the time. Breathe deeply, get up and stretch your neck, arms and shoulders, roll your shoulders clockwise and anticlockwise, clasp your hands behind your back and lift your arms, shake your legs, drink herbal tea, look out the window. This will prevent tension headaches and neck muscle spasm.

• Become aware of the basics of ergonomics: invest in a good quality chair that follow the curve of your back, your upper legs should be straight, knees bent, lower legs perpendicular to upper legs, feet comfortably flat on the floor. Elbows, forearms and hands should be in line with the keyboard. Fresh clean air should circulate freely. There should be greenery near you – a pot plant, fresh flowers, your own small herbal garden in a pot.

• Stress busting food tips-

Prevent low blood sugar – it’s a stress attractor! Eat regular, healthy, small meals. Always have fruit, veges, nuts and seeds handy!- Sip away your stress: chamomile, mint, passionflower, lemon balm, ginseng, lavender, valerian herbal teas, together with a spoonful of honey will soothe frazzled nerves- Calming foods: tryptophane boosts the formation of serotonin, the ‘feel good’, calming brain chemical - eat unrefined carbohydrates, nuts and bananas- Energising foods: small amounts of protein (cheese, eggs, chicken, meat) contains the amino acid tryptamine that can give you a boost when stress tires you out. Take small ready prepared portions to work. - Take a daily dose of vitamin B-complex to support your nervous system together with an antioxidant and multivitamin combination (vitamin A, E, C, minerals zinc, selenium, copper, chromium, iron, calcium and magnesium)- Use the herb Ginkgo biloba to boost your concentration and memory- Food for thought: beans / legumes, lean meat, whole grain and enriched cereals, poultry, fish such as trout, salmon, tuna, sardines and mackerel, dairy products, brewer’s yeast, nuts, seeds, fruit, vegetables

• Become quite, focused, aware

Rather than a worry, fear or anger response to triggers: become quiet, focused, aware of your feelings around the stressful experience, consciously relax by slowing down your breathing. When deeply upset, you can’t always change the feeling, but you can slow down and deepen your own breath. Doing this regularly, will teach you to react pro-actively: responding rather than reacting to stress triggers. Use the female tend-and-befriend’ stress response. Women (and female animals form all species) experiencing stress tend to nurture themselves and their young and form bonds with others. Women also have the classical fight-or-flight response under stress, but the tend-and-befriend response seems to take effect during long term chronic stress. Female animals need to protect their young in a stressful situation – as did our ancestors and ourselves even today, when physically threatened. Fleeing too soon might leave a young animal defenseless. So use it, by forming networks and support groups with others. Relax and unwind over a cup of coffee or lunch. It’s a survival mechanism! Men will of course also benefit from the tend-and-befriend response!

• Develop the inner awareness of a soul having a physical experience

Feelings of stress or anxiety may also be your soul's way of telling you to attend to your spiritual needs. The inspiration gained from spirituality is an essential part of stress management. Mind, body, and spirit are inseparable. Establishing a firm connection to your spirit will provide healing for your mind and body. You can deepen your commitment to spirituality through any of the following: creating a sacred space in your home or at work: decorate it with colourful textured cloth, arrange crystals or stones, hang crystals or wind chimes inside an open door or window, look at pictures of your loved ones, a special painting and a burner with aromatherapy oil. Connect with it every day in mindful awareness of your soul’s purpose on earth. Other soul connections: regular participation in church or your preferred spiritually based organisation, read inspirational literature of your preference, write in your journal: your life story, your ancestors’ stories; contemplate your dreams, myths and restore rituals; have a 10-20 minute meditation session every day; use spiritual affirmations and prayers.

By: Dr Arien van der Merwe
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Written by Dr Arien van der Merwe, medical doctor, specialist corporate health & wellness service provider and author of”>Stress Solutions, ‘Relax & Unwind’ a relaxation CD, Health & Happiness Also Training manuals on Wellness/Peer Education, Stress Management and Workplace Wellness. For more info & to order:”" target="_blank">”