Elasticity

September 15, 2011 by · Leave a Comment 

tufailIn physics, elasticity (or stretchiness) is the physical property of a material that returns to its original shape after the stress (e.g. external forces) that made it deform or distort is removed. The relative amount of deformation is called the strain.

The elastic regime is characterized by a linear relationship between stress and strain, denoted linear elasticity. The classic example is a metal spring. This idea was first stated by Robert Hooke in 1675 as a Latin anagram “ceiiinossssttuu” whose solution he published in 1678 as “Ut tensio, sic vis” which means “As the extension, so the force.”

This linear relationship is called Hooke’s law. The classic model of linear elasticity is the perfect spring. Although the general proportionality constant between stress and strain in three dimensions is a 4th order tensor, when considering simple situations of higher symmetry such as a rod in one dimensional loading, the relationship may often be reduced to applications of Hooke’s law.

Because most materials are elastic only under relatively small deformations, several assumptions are used to linearize the theory. Most importantly, higher order terms are generally discarded based on the small deformation assumption. In certain special cases, such as when considering a rubbery material, these assumptions may not be permissible. However, in general, elasticity refers to the linearized theory of the continuum stresses and strains.

Above a certain stress known as the elastic limit or the yield strength of an elastic material, the relationship between stress and strain becomes nonlinear. Beyond this limit, the solid may deform irreversibly, exhibiting plasticity. A stress-strain curve is one tool for visualizing this transition.

Furthermore, not only solids exhibit elasticity. Some non-Newtonian fluids, such as viscoelastic fluids, will also exhibit elasticity in certain conditions. In response to a small, rapidly applied and removed strain, these fluids may deform and then return to their original shape. Under larger strains, or strains applied for longer periods of time, these fluids may start to flow like a liquid, with some viscosity.

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Post-Traumatic Stress: The Disability of Our Time

August 18, 2011 by · Leave a Comment 

By Karin Friedemann, TMO

Post-Traumatic Stress Disorder is a psychological problem that can affect people from any part of the globe, and from every social class. We can all sympathize with someone who lost his mind after his family got swept away by a tsunami. We have all heard stories of war veterans who were no longer the same after they came back home. Yet PTSD can also be triggered by seemingly minor events, such as being punished as a child for a misdeed one didn’t commit. It is increasingly documented that women involved with men on the autism spectrum are extremely likely to suffer from PTSD due to the constant emotional trauma of caring for a person disabled by a neurological disorder, which prevents him from responding appropriately to the needs of others.

PTSD was not labeled as a psychiatric disorder until 1980, but people have suffered from PTSD throughout the history of mankind. During the American Civil War it was called “Soldier’s Heart.” It is possible that the prevalence of PTSD has increased in recent years due to the ability to access graphic news on TV and the internet. Humans are now able to see traumatic events all over the world and some people have trouble coping with the images. On the other hand, the general public’s increasing emotional numbness to exposure to painful world events or even violent video games is also worrying and perhaps even more dangerous from a clinical standpoint.

People respond to emotional stress very differently. Some people can witness a barbaric event and yet bounce back and go on to lead healthy productive lives, but some people find they cannot recover their emotional balance after a negative experience. Some negative experiences are so shocking that they shake a person to their core. Yet some negative experiences are ongoing everyday experiences that undermine a person’s self-worth, and can also result in long lasting psychological damage.

People are best able to cope with negative life experiences when they have a deep emotional reservoir of positive life experiences and trust-based relationships. A person with a solid foundation of self-esteem and love can eventually heal from something as terrible as witnessing a murder while someone with a poor sense of self could fall apart just because his home went into foreclosure. Some people are simply more sensitive than others. It’s often hard to predict how one will react to traumatic stress until it happens. Having a history of trauma may increase one’s risk of getting PTSD after a recent traumatic event. There is a huge connection between childhood neglect or mistreatment and a person’s inability to process negative emotions.

While traumatic stress is happening, a person tends to block out the pain or reinterpret events in order to deal with the present situation. However, in the weeks, months, and years after the emotional trauma has passed, the person remains unable to cope effectively because of the memory of the pain. PTSD is characterized by periodic disconnect from present reality, where one’s mind relives a past event over and over, fully experiencing the emotions of that event as if it were happening now. One clue that one is not processing one’s stress effectively is when one feels exhausted during the day and falls asleep on time, yet wakes in the night burdened by repetitive thoughts and cannot go back to sleep for hours. Some people are even afraid to go to sleep due to nightmares or images in their minds.

Other symptoms of PTSD include disinterest in normal everyday activities, avoiding things that remind one of that event, emotional numbness, startling easily, hyper-vigilance, paranoia, erratic heartbeat, fainting, inordinately angry outbursts, intense shame and guilt, and a constant sense of danger. Traumatized children may develop irrational phobias, lose their toilet training, and often relive their trauma in play. Palestinian children whose homes have been destroyed by the Israelis have often been documented building play houses, or wetting themselves when they hear loud noises.

According to US statistics, about 7 percent to 8 percent of the general population will develop PTSD. These numbers go up significantly for veterans and rape victims, among whom PTSD has anywhere from a 10 percent to 30 percent chance of developing. Women war veterans experience PTSD far more severely than their male counterparts.

PTSD is clinically treated with calming medication and/or psychological counseling. Many people experiencing PTSD self-medicate with alcohol while the lucky ones find solace in supportive relationships.

The process of healing from PTSD requires going through a full grieving and healing process so that one can learn and grow from the negative life experience instead of letting it hold one back from truly living. Healing also involves learning how to set internal boundaries against past and present abusers in one’s life as well as learning to steer one’s mind away from bad thoughts. It may help to keep a journal of one’s feelings or to make a schedule where one records the time lost daily ruminating about painful past events or conversations.

It is important to understand that PTSD is not a sign of weakness or cowardice but actually points to a strongly developed conscience and higher than average emotional intelligence. The only way to overcome PTSD is to confront what happened to you and learn to accept it as a part of your past while learning how to minimize stress and anxiety in your current life.

Karin Friedemann is a Boston-based freelance writer.

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Fault Lines

June 30, 2011 by · Leave a Comment 

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Normal faults generally occur in places where the lithosphere is being stretched. Consequently they are the chief structural components of many sedimentary rift basins (e.g. the North Sea) where they have major significance for hydrocarbon exploration. They can also be found in deltas, at the rear edges of huge gravitation slumps and slides. Normal faults can show different geometries – and a few are shown here. In some situations the faults can become gently dipping at depth so that they have a spoon (or listric) shape. Other normal faults are found in batches, dipping in the same direction, with rotated fault blocks between. These are termed domino faults. Although most active normal faults can be shown to dip at angles steeper than 50 degrees, there are examples of very low-angle normal faults. These are often termed “detachments” – although this is a pretty vague term! Detachments show gentle dips and often expose high grade metamorphic rocks in their footwalls. These footwalls can be termed metamorphic core complexes. Normal faulting is now thought to be an important way in which metamorphic rocks come to be at the earth’s surface today.

Thrusts are reverse faults and commonly dominate the structure of collision mountain belts. Some thrusts have moved a long way – many mountain belts have thrusts that have moved many tens of kilometers. The photograph above shows one such structure from the Alps – which carries basement of the Mont Blanc massif onto Jurassic sediments. Many thrusts can be shown to follow so-called staircase trajectories. Otherwise, explore the nature of thrust systems by selecting from the icons. The material introduces concepts used in the Leeds first year structure course but some aspects are suited to higher level studies.

Strike-slip faults include some of the world’s most famous – or infamous structures, including the San Andreas Fault system and the North Anatolian Fault system. Both of these are renowned for devastating earthquakes. Strike-slip faults are those where the relative displacement is parallel to the strike of the fault. Strike-slip fault zones are commonly, but by no means exclusively, steep and can be rather difficult to recognize on cross-sections. 

All structures form in response to forces acting on rocks – and these give rise to stresses. In almost all geological situations stresses are always compressive but vary in different directions. We can evaluate the stress state in terms of the orientation and magnitudes of the so-called three principal stresses – which each act at 90 degrees to each other (i.e. they are orthogonal). Conventionally these are denoted using the Greek letter “sigma”. Patterns of conjugate faults – provided they formed together – can be related to the orientations of the principal stress axes.

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Bahrain Foreign Minister’s India Visit

April 7, 2011 by · Leave a Comment 

By Nilofar Suhrawardy, TMO

NEW DELHI: Bahrain Foreign Minister Sheikh Khalid Bin Ahmed Bin Mohammed Al-Khalifa was in India last month as a part of diplomatic drive to assure the Indian government about the security of Indians living there. He held detailed discussions with his Indian counterpart SM Krishna on issues of mutual interest, including recent developments in Bahrain and the region (March 30). Ahead of their talks, the two ministers laid stress on “traditionally friendly relations” between India and Bahrain, “which are based on historical and civilizational ties.” This “long standing relationship” is reflected by presence of a large Indian community in Bahrain.

During their meeting, over lunch hosted by India in his honor, Bahraini foreign minister gave “firm assurance” about “safety and security of Indian community” in Bahrain. He also appreciated their contribution to “progress and development of Bahrain.” There are around 350,000 Indians in Bahrain. Khalid drew Krishna’s attention to his having met more than 200 Indians in Manama on 26th March, 2011. On his part, Krishna thanked Khalid for his reassurance with regard to Indian community’s well being. The former also expressed confidence that “law-abiding Indian community would continue to be a partner in Bahrain’s growth story well into the future.”

Referring to recent developments in Bahrain, Krishna expressed the hope that “peaceful resolution of all issues through dialogue would pave the way for continued development and prosperity of friendly people of Bahrain.”

During an exclusive interview with this scribe, Khalid acknowledged: “There is no doubt a wave of transformation in the Arab world.” Accepting that winds of transformation were sweeping across the region, he pointed to the human development index in the six Gulf Coordination Council countries – Bahrain, Kuwait, Oman, Saudi Arabia, United Arab Emirates and Qatar – being much higher than that of other countries. In other parts of the region, the people on the lower end of the scale were vying for a change, he said. Referring specifically to Bahrain, he said that though sectarian tensions between Sunnis and Shias have prevailed for “around 1400 years,” they have taken such a major turn for first time, reaching the “stage of polarization.” “Sectarian turn is the biggest threat to whole region,” he said.

Laying stress that there was a need for “true transformation” in many parts of the area, Khalid expressed that this “movement” had been “hijacked and had taken a sectarian turn” between Sunnis and Shias. Expressing favor for a political dialogue to sort out the problem, he said: “Political dialogue would be way forward in future.” The priority at present was to maintain law and order, Khalid emphasized.

Refuting the impression generated about Bahrain taking help of Saudi forces to control protestors, Khalid said that these belonged to Peninsula Shield Force. “We take our security seriously,” he stated. The troops would stay as long as they were needed, he said. Khalid specified that their help was essential to prevent the tension from escalating into a civil strife. The situation was “under control,” he said.

A “very negligible” population had left Bahrain because of tension in the country, he said. Though certain elements’ aim was to scare the expat community, Indians were not targeted, he emphasized. “I am visiting India before Europe or America. This is more important. We are regional stakeholders. Without India, we do not have a solution. We need to reassure India about the Indian community in Bahrain,” the minister asserted.

Elaborating on security architecture in the region, Bahrain cannot envisage this without India, Khalid said. India’s Deputy National Security Advisor Vijaya Latha Reddy called on Khalid ahead of his meeting with Krishna. She discussed issues of bilateral interest with him.

Bahrain also favors a role for Pakistan as well as Iran. “We want Iran to be part of this security architecture. We want it to prosper and be as active as in the past as a responsible country in the region,” he said.

Without elaborating on diplomatic tension between Bahrain and Iran, Khalid categorically stated: “We are for good relations with Iran.” “The result of bad relations with a neighbor can be more lethal than that of a nuclear bomb,” he said.

Diplomatic tension between Bahrain and Iran has been marked by the former holding latter as responsible for provoking Shia-Sunni tension in the region. Bahrain has warned Iran to keep away from “meddling” in its internal affairs. On its part, Iran has strongly criticized the arrival of external troops in Bahrain.

Bahrain is also not pleased with external strikes supporting rebels in Libya. When asked to comment on this, Khalid said that Bahrain had no objection to maintaining a “no-fly zone” over Libya. He was, however, skeptical about role of external strikes. “We were a part of the GCC and Arab League resolutions supporting no-fly zone. But we feel there is no clarity whether external strikes can really help in protection of people and their security.”

This was Khalid’s second visit to India. His visit, according to official sources, “has strengthened the excellent relationship between the two countries.”

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Renewal of Yourself First

January 14, 2010 by · Leave a Comment 

By Imam Abdullah El-Amin, MMNS

The tenets of the religion of Al-Islam emphasize constant renewal in our lives.  If we could just do something once and be done with it, our practice of the religion would cease to exist.  For instance, we are directed to fast every year in Ramadan.  This is because one time just won’t do it.  We will forget and/or lapse into other activities to divert our attention from the remembrance of ALLAH, so He orders us to fast each year.

There are many other signs from ALLAH for us to reflect on.  We breathe, eat and drink everyday to replenish our bodies.  If we did not…well you know the answer to that.  There is also constant renewal in education.  Our brains need activity to grow and be useful.

Similarly, our relationships must also be constantly renewed.  How many of us have heard the expression “What you did to get her, you must also do to keep her?”
But before we get to that; before reaching out to our spouses, we must reach out to ourselves.  In order to spread cheer to our families, spouses, and others, it must first come from a cheerful body and mind.  How is this accomplished?

Each day upon rising we must begin to renew ourselves by recognizing the great masterful work of art ALLAH formed when He created you.  You must look in the mirror and say to yourself how good you look.  Arm your mind with positive thoughts and keep the evil ones (Shatan) from convincing you that you are otherwise.

After recognition of your greatness, resolve to be grateful to ALLAH by taking care of this great creation – you.  Make sure you bathe and keep yourself clean.  Shampoo your hair and use conditioner to enhance its appearance and health.  Try to eat sensibly to reduce stress on your body.  Exercise at least moderately to keep your temple in the best shape.

Above all, try to live as uneventful a life as possible.  We learn in science that the brain responds to stress by secreting a hormone called cortisol.  This chemical balances the stress levels in your body and helps you to cope with the ups and downs of your life.  We know everybody has stress but it’s smart to keep it to a minimum because too much secretion of this cortisol is harmful to your body.  It causes excess plaque build-up in the blood vessels and contributes to heart attack, stroke, diabetes, and many other ailments.  These are things that could be prevented by living a moderate life as dictated by your Creator, Almighty ALLAH.

So when you concentrate on this constant renewal of yourself, it will make you grateful and put you in the best possible position to reach out to others.  We will be able to love and see the benefit and beauty of our spouse and help them see the benefit and beauty of themselves.  This is very important because then everybody wins and ALLAH is pleased because you are carrying out His desires for creating you in the first place.  And if ALLAH is pleased with you, you can ask for no better reward.

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India Wants “Peace” with Pakistan

July 2, 2009 by · 1 Comment 

By Nilofar Suhrawardy, MMNS India Correspondent

NEW DELHI: Indo-Pak talks have been on hold since Mumbai-strikes in November last year. The two sides agreed to revive talks at first top-level contact last month in Russia on sidelines of a summit. Indian Prime Minister Manmohan Singh held talks with Pakistan President Asif Ali Zardari (June 16). On his return, while briefing media on his Russia-visit, regarding his talks with Zardari, Singh said: “We discussed India-Pakistan relations, which remain under considerable stress. The primary cause of this, as everyone knows, is terrorist attacks against India from Pakistani territory. I conveyed to President Zardari the full extent of our expectation that the Government of Pakistan take strong and effective action to prevent use of Pakistan’s territory for terrorist attacks against India, act against perpetrators of past attacks and dismantle infrastructure of terrorism in Pakistan. The President of Pakistan told me of Pakistan’s efforts to deal with this menace and the difficulties that they face.” “We agreed that our foreign secretaries will discuss what Pakistan is doing and can do to prevent terrorism from Pakistan against India and to bring those responsible for these attacks to justice including the horrendous crime of the attacks in Mumbai. They will report to us and we will take stock of the situation when we are at Sharm-el-Sheikh for the Non-aligned Summit in mid-July,” Singh said.

“I have spoken before of my vision of a cooperative subcontinent, and of the vital interest that India and the people of the subcontinent have in peace. For this we must try again to make peace with Pakistan. It also requires effective and strong action against the enemies of peace. If the leaders of Pakistan have the courage, determination and statesmanship to take the high road to peace, India will meet them more than half-way,” Singh said.

Undeniably, Singh’s comments suggest that India and Pakistan are making most of opportunities available to discuss terrorism and revival of their stalled talks. It was with this aim that Singh held talks with Zardari, without any “structured agenda.” During their talks, they also set the stage for subsequent meetings between them and at other levels. Not surprisingly, Indian External Affairs Minister S.M. Krishna met his Pakistani counterpart Shah Mehmood Qureshi, on sidelines of G8 Outreach Af-Pak Summit in Italy’s Trieste city (June 26). It was the second high-level contact in a month. After his meeting with Qureshi, Krishna told media: “I am glad that this international conference has provided an opportunity for bilateral meeting with my counterpart from Pakistan.” The two ministers reviewed current status of Indo-Pak relations, which have remained under “considerable stress” because of terrorist attacks on India by elements based in Pakistan, Krishna said. They agreed on “vast potential that exist in India-Pakistan relations.” Krishna conveyed New Delhi’s stand, that India is “ready to meet Pakistan more than half way to utilize and harness that potential for our mutual benefit. At the same time, we have to address centrally why our relations come under stress recurrently.”

Efforts being made to bring Indo-Pak ties on track assume significance, as United States is also keen on improvement in their bilateral relations. In keeping with Af-Pak policy being pursued by President Barack Obama, United States National Security Adviser James Jones was here last week after stops in Afghanistan and Pakistan. Jones held separate talks with Prime Minister Manmohan Singh, his Indian counterpart M.K. Narayanan and other Indian leaders (June 26). Jones is first high-ranking US official to visit India following India and Pakistan’s agreement to revive stalled talks and discuss steps taken by Islamabad on tackling terrorism targeting India by militants based in Pakistan. Jones’ visit also assumes significance with it taking place ahead of proposed visit of US Secretary of State Hillary Clinton this month.

The key issues touched on during talks Jones held with Indian leaders were: “Pakistan and terrorism emanating from there against India.” Jones is also understood to have shared his assessment of situation in Afghanistan and Pakistan, where operations are continuing against Taliban militants. During his talks in Islamabad and New Delhi, Jones laid stress that attacks such as Mumbai-strikes must be prevented, according to sources. He also “vowed” United States’ move to help India and Pakistan improve their ties and combat militant threat.

In Washington, Assistant Secretary of State for South and Central Asia, Robert O. Blake told a panel of House of Representatives last week: “India and Pakistan face common challenges, and we will support continuing dialogue to find joint solutions to counter terrorism and to promote regional stability.” “The timing, scope, and content of any such dialogue are strictly matters for Pakistani and Indian leaders to decide,” he said.

Though India remains dissatisfied with Pakistan having not taken necessary steps against those responsible for Mumbai-strikes, there is no doubt that two countries have displayed serious interest in recent past to revive their talks. Indian Defense Minister A.K. Antony told a group of senior military commanders last week: “We must be vigilant about happenings on our western border, while at the same time, try to make peace with our neighbor.” Asserting that India should not be viewed as a “threat” by Pakistan, Chief of Army Staff Deepak Kapoor said: “It’s their own perception of threat, but India has never been a threat to Pakistan despite having superior forces” (June 27). Speaking to newsmen at the Combined Graduation Parade of the Indian Air Force cadets at the Air Force Academy at Dindigul near Hyderabad, he said: “We on our side like to live as peaceful neighbors. We will be happy if Pakistan fights terror not only on its western borders but also on the eastern border.”

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