Voice of Progress

A Sample Problem.

Find the electric field at a distance $z$ above the midpoint of a straight line segment of length $2L$ , which carries a uniform line charge $\lambda$ .

Solution: It is advantageous to chop the line up into symmetrically placed pairs ( at $\pm x$ ), for then the horizontal components of the two fields cancel, and the net field of the pair is

$\begin{equation*} d \textbf{E} = 2 \frac {1} {4 \pi \epsilon_0} \left ( \frac { \lambda ~ dx} { \textit {r} ^2} \right) \cos\theta ~ \hat{ \textbf{z}}. \end{equation*}$

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Here $\cos \theta = z/r$ , $r = \sqrt { z^2 + x^2 }$ , and $x$ runs from $0$ to $L$ :

$\begin{eqnarray*} E & = & \frac {1} {4 \pi \epsilon_0} \int ^L _0 \frac {2\lambda z} { (z^2 + x^2 )^{3/2} }dx \\ &=& \frac {2 \lambda z} {4 \pi \epsilon_0} \left[ \frac {x} { z^2 \sqrt {z^2 + x^2 } }\right ] ^L _0 \\ &=& \frac {1} {4 \pi \epsilon_0} \frac {2\lambda L} {z \sqrt {z^2 + L^2}}. \end{eqnarray*}$

and it aims in the $z$ -direction.

For points far from the line $( z >> L )$ , this result simplifies:

$\begin{equation*} E \cong \frac {1} { 4 \pi \epsilon_0} \frac {2 \lambda L} { z^2} , \end{equation*}$

which makes sense: From far away the line “looks” like a point charge $q = 2 \lambda L$ , so the field reduces to that of a point charge $q/ ( 4 \pi \epsilon_0 z^2 )$ . In the limit $L \longrightarrow \infty$ , on the other hand, we obtain the field of an infinite straight wire:

$\begin{equation*} E & = & \frac {1} { 4 \pi \epsilon_0} \frac {2 \lambda} { z} ; \end{equation*}$

where $z$ is the distance from the wire.

May 5, 2011

CONFIDENCE

Spirituality

(This talk was given by Sri Chinmoy at University of Cambridge; Cambridge, England on 21 June 1976)

Dear friends, dear brothers and sisters, dear seekers, I wish to give a short talk on confidence. Here we are in Cambridge. Cambridge immediately awakens confidence in us. What we call confidence in the outer world is nothing short of assurance in the inner world. Therefore, I bow to the confidence and the assurance in Cambridge.

Confidence awakens our physical. Confidence energises our vital. Confidence illumines our mind. Confidence purifies our heart. A pure heart, an illumined mind, an energetic and dynamic vital and a wakeful body can and will manifest the divine realities here on earth.

Confidence is a divine revelation of our inner assurance. There is an unseen reality within us, a divine Pilot, an Inner Pilot who moulds and shapes our lives. When we hear the message of the Inner Pilot, in our outer life we feel confidence. Confidence is an outer gift from Above, whereas assurance is an inner gift from Above.

Confidence is self-awareness. We want to be aware of ourselves. We want to know what our source is, where we came from, what we are doing here on earth. We want to know our respective roles in this Cosmic Game, this Lila. Our confidence brings to the fore the inner vision, the reality that we are aiming at, that we want to grow into.

Confidence is not a display of our egocentric life. Confidence is a divine force. Ego binds us and blinds us. Ego offers us the message of separativity and self- enjoyment. Confidence, on the other hand, wants to express its universal oneness. It is for all; it is for the Infinite, the Vast. Confidence cannot be satisfied all by itself. It wants to grow into the Universal Light and Transcendental Height.

When we have confidence in ourselves, we realise the Ultimate Truth and Light, the Absolute Supreme. When God has confidence in us, He makes us not only His perfect instruments, but conscious representatives of His Divinity, His Reality, His Infinity, His Eternity and His Immortality on earth. With our confidence in God, we go up and reach His Transcendental Height. With God’s Confidence in us, God comes down and makes us His Infinity, His Eternity, His Immortality. And this is not the end of His Game. Then He wants us to manifest what we have become.

Confidence is introduction. Confidence introduces our earthly reality to the divine Reality. And the divine Reality introduces its wealth—infinite Peace, Light and Bliss—to us when we are confident.

Life is either meaningful or meaningless. For those who do not seek, life is meaningless, a barren desert. For seekers, at every moment life is meaningful and fruitful; life has a purpose, a meaning, a reality and an Ultimate Goal. What brings us the message of the Ultimate Goal, what brings us the reality of the inner world, the more illumining, more fulfilling higher world? It is our confidence. With our confidence-light, we dig deep within and, while digging within, we cultivate the bumper-crop of realisation, liberation and perfection.

An unaspiring person talks to himself and talks to the world. But he cannot talk to the Ultimate Reality. It is only a man of confidence, inner confidence, divine confidence, supreme confidence who can talk to the highest Reality: the Transcendental Vision and the Universal Reality.

One portion of divinity comes down into the world and another remains Above. The one that remains Above is known as the Father-Reality and the one that comes down is known as the Son-Reality. Again, there comes a time when the two realities become inseparably one and tell the world of their oneness. Jesus Christ, the Saviour, announced, “I and my Father are one.” His confidence-light he brought down into the world; and it was his confidence-light that uttered, “I and my Father are one.” When Divinity enters into humanity and illumines humanity, at that time humanity claims Divinity as its very own.

Confidence is oneness with the Beyond, the oneness of earth-life with Heaven-life. Where God is, confidence is bound to be. God has given us the secret key to open up His Heart’s Door and that secret key is confidence. We pray, we meditate, only to cultivate one divine quality and that one divine quality is confidence. Confidence shows us the way to go ahead, the way to dive deep within, the way to fly above. Confidence is the pioneer that constantly leads us, guides us, beckons us to the Ultimate Source.

Each individual has teeming questions: “Who am I? Where do I come from? What is my Ultimate Goal?” All the questions of our inner and outer life can be answered by one solitary thing: confidence. If we have confidence, then we can explore the inner world. If we have confidence, then we can explore the outer world.

Here we are all seekers. We want to know the reality that we eternally are and that we are going to offer to the world at large. And for that what we need is perfection, self-perfection. It is only in self-perfection that we can please the Inner Pilot, the Supreme Pilot, the world around us, the world within us. This perfection is our constant confidence in ourselves and in our Inner Pilot.

Again, this confidence has a Source. Its Source is God’s Compassion-Light and Compassion-Delight. God grants us Light in boundless measure at our journey’s start. And it is He, the Supreme, the Eternal Pilot, who grants us eternal, boundless Delight as we continue along the way. Light energises us. Light leads us, guides us to our Ultimate Destination, where we see the transformation of Light into Delight. Delight fulfils us. Delight immortalises us.

We aspire to become good, to become loving, to become devoted, to become useful to the world at large. But this aspiration also needs something from us. It is confidence that aspiration expects from each seeker. If the seeker is wanting in confidence, then his aspiration can never be regular, it can never be spontaneous, it can never be continuous. But if, inside his aspiration, confidence looms large, then he walks along a sunlit road to his Destined Goal.

A child has confidence in his parents. He feels that his parents know everything, have everything and are everything for him. Similarly, a seeker has all confidence in his Inner Pilot, the Supreme, who is guiding his destiny, his life, his aspiration, his realisation, his reality to the Ultimate Goal.

Each day we are granted by the Author of all good, out of His infinite Bounty, confidence both in our inner life and in our outer life. But if we use our physical mind—our earth-bound, sophisticated, obscure, unlit, unaspiring, intellectual mind—to search, we may not feel God’s Confidence-Light. For the earth-bound mind feels that it is complete in itself; it does not need any reality other than its own existence.

But the heart constantly feels that it can house something more, that it can see something more, that it can grow into something more, that it has something more to offer to the world at large. The heart has the eagerness to receive and to achieve from the world within and from the world without. The heart has a constant, inner thirst to be universal, to be transcendental. Therefore, the heart always looks within and around to grasp and invoke the infinite Realities that abide in God’s entire Creation. The heart comes to realise that there is only one way to achieve and grow into these infinite Realities and that is the way of self-giving. What is self-giving today, tomorrow that very thing is God-becoming. On the strength of self-giving, our aspiring heart becomes both universal and transcendental. This self-giving heart has a source of its own and that source is confidence. Confidence also has its source. Its source is God’s Compassion, God’s infinite, unconditional, immortal Compassion in man, for man.

April 28, 2011

Sri Chinmoy Answers – Series 1

Philosophy

Question: What is the best way to get creative inspiration?

Sri Chinmoy: The best way to receive inspiration is through inner aspiration and outer dedication to the one cause. That cause is self-discovery.

Question: Is there a highest art form?

Sri Chinmoy: Yes, the highest art form, the absolutely highest art, the supreme art for a seeker, is the art of God-realisation. God-realisation has to be achieved through aspiration and dedication. Aspiration and dedication go together. If you become a musician for your livelihood, you have to feel that your work is not work, but is a dedicated service to the Supreme. If you take it as work, a kind of work you do in order to make money, then it is not art. When you are playing, you have to aspire to reach the Highest, and you have to feel that you are dedicating your capacity, your willingness, or your achievement to the Supreme in yourself. If you do that, it is the best art on earth, the highest supreme art in your life of aspiration.

April 28, 2011

Poetry of Sri Chinmoy – 1

Poetry

I call it life.

My soul calls it beauty’s temple.

I call it death.

My soul calls it purity’s shrine.

~~~~~~~~

O my heart,

Can you not become

A climbing sun?

O my life,

Can you not become

An expanding sky?

~~~~~~~~

As a doubting mind

Finds no comfort on earth,

Even so a loving heart

Finds no comfort in the grave.

~~~~~~~~

April 28, 2011

Graphene quantum dots embedded within graphane

Physics

Graphene is a one-atom thick sheet of carbon that stacks with other such sheets to form graphite— the main component of pencil “lead.” The pure, flawless crystal conducts electricity faster at room temperature than any other substance.

Graphane is simply graphene modified by hydrogen atoms added to both sides of the matrix, which makes it an insulator. While it’s still technically only a single atom thick, graphane offers great possibilities for the manipulation of the material’s semiconducting properties.

Quantum dots

Quantum dots, also called artificial atoms are really made up of more than one atom, but behave like single atoms in one important way: when you provide the right amount (or quanta) of energy, they will give off coloured light. So when you brighten a quantum dot with the right amount of energy, just like an atom, it will absorb that energy and then give off photons of only particular wavelengths. The wavelengths are determined by the size of the dot, which depends on the number of atoms that make up the dot. A typical artificial atom or quantum dot has dimensions of only 1 to 100 nanometres (1 nanometer is billionth of a meter) and contain somewhere between 1000 and 1000,000 atomic nuclei. The size of a dot determines its band gap – the amount of energy needed to close the circuit – and makes it tunable to a precise degree. The frequencies of light and energy released by activated dots make them particularly useful for chemical sensors, solar cells, medical imaging and nanoscale circuitry. (http://www.voiceofprogress.com/?p=4868)

Graphene quantum dots embedded within graphane

Rice university researchers – Abhishek Singh and Evgeni Penev, both postdoctoral researchers mentored by Professor Boris Yakobson have discovered (based on their theoretical work) that the strategic extraction of hydrogen atoms from a two-dimensional sheet of graphane naturally opens up spaces of pure graphene that look – and act – like quantum dots.

Singh and Penev calculated that removing islands of hydrogen from both sides of a graphane matrix leaves a well (graphene) with all the properties of quantum dots, which may also be useful in creating arrays of dots for many applications.

Their work revealed several interesting characteristics. They found that when chunks of the hydrogen sublattice are removed, the area left behind is always hexagonal, with a sharp interface between the graphene and graphane. This is important, they said, because it means each dot is highly contained; calculations show very little leakage of charge into the graphane host material. (How, precisely, to remove hydrogen atoms from the lattice remains a question for materials scientists, who are working on it, they said.)

The work done by Singh and Penev opens up a new world of possibilities in a class of nanoelectronics that depend on the highly controllable semiconducting properties of quantum dots, particularly in the realm of advanced optics.

Singh said, “You have an atom-like spectra embedded within a media, and then you can play with the band gap by changing the size of the dot. You can essentially tune the optical properties.”

According to Singh along with optical applications, the dots may be useful in single-molecule sensing and could lead to very tiny transistors or semiconductor lasers.

Challenges remain in figuring out how to make arrays of quantum dots in a sheet of graphane, but neither Singh nor Penev sees the obstacles as insurmountable.

Professor Yakobson said, “We arrived at these ideas from an entirely different study of energy storage in a form of hydrogen adsorption on graphene. Abhishek and Evgeni realized that this phase transformation (from graphene to graphane), accompanied by the change from metal to insulator, offers a novel palette for nanoengineering.”

When might their calculations bear commercial fruit?

Singh said, “That’s a tough question. It won’t be that far, probably — but there are challenges. I don’t know that we can give it a time frame, but it could happen soon. We think the major conclusions in the paper are enough to excite experimentalists. Some are already working in the directions we explored.”

“Their work is actually supporting what we’re suggesting, that you can do this patterning in a controlled way,” Penev said.

Source: http://www.media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=14302

May 26, 2010

Need for restoring degraded ecosystems

Environment

Ecosystem services: These are multitude of resources and processes that are supplied by natural ecosystems from which mankind benefits. These include direct ecosystem services such as pollination, wood, & erosion prevention and indirect services such as climate moderation, nutrient cycles, and detoxifying natural substances. The ecosystem services are grouped into four broad categories: provisioning, such as the production of food and water; regulating, such as the control of climate and disease; supporting, such as nutrient cycles and crop pollination; and cultural, such as spiritual and recreational benefits.

Ecological restoration is the intentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainability. The practice of ecological restoration includes erosion control, reforestation, removal of non-native species and weeds, revegetation of disturbed areas, daylighting streams, reintroduction of native species, as well as habitat and range improvement for targeted species.

According to researchers from the University of Alcalá, Centre for Ecology & Hydrology and Bournemouth University, ecological restoration in areas of environmental degradation can help reverse global biodiversity (variation of life forms within a given ecosystem) losses.

For their study the research team analysed results from 89 restoration assessments carried out in a wide range of ecosystem types across the globe. On average, ecological restoration increased provision of biodiversity and ecosystem services by 44% and 25% respectively.

At the same time the scientists also noted that measures of biodiversity and ecosystem services are still higher in intact, undamaged reference ecosystems than in restored systems. From this the researchers concluded that it was not only important to apply ecological restoration approaches for addressing environmental degradation in many parts of the world but it was equally important to conserve the intact, undamaged ecosystems.

One of the researchers Professor James Bullock said, “We have shown that across the globe restoration projects are able to help reverse loss of the biodiversity and ecosystem services in areas degraded by human activities. While restoration can help reverse losses, this research shows it is critical for human well-being that we conserve pristine habitats and the biodiversity and ecosystem services they provide.”

Another researcher Professor Adrian Newton, from Bournemouth University said: “These results highlight the importance of ecological restoration approaches for addressing the environmental degradation that has occurred in many parts of the world. The research suggests that restoration can offer a ‘win-win’ solution, by increasing the provision of environmental benefits to people, while at the same time increasing biodiversity.”

Researchers also noted that restoring degraded ecosystems also is a source of green employment.

September 9, 2009

Repeated blows to the head may damage the brain

Medicine

Researchers at the Sahlgrenska Academy at University of Gothenburg and the Erciyes University Medical School in Turkey have found evidence that repeated blows to the head may damage the brain.

For their study they collected samples from 44 Turkish amateur boxers in the beginning of a training camp after a two-month break from boxing. They analyzed these blood samples and compared the results to those found in a healthy control group. The researchers analyzed several proteins that can be used to identify brain damage, and found that the levels of one protein, called NSE (Neuron-specific enolase), were higher among the boxers than in the control group. Henrik Zetterberg, at the Sahlgrenska Academy says, “Their levels were high even after two months off from boxing. This indicates that the harmful processes in the brain continue even if the boxers have not recently experienced head trauma. The blows seem to lead to a deterioration of nerve cells that lasts for a relatively long time. It is important that this is made known to participants in sports that involve kicks and blows to the head and to parents who let their children participate”.

Explaining the importance of their study Zetterberg said, “A blood test is much easier to take, and it would be interesting to test athletes repeatedly following matches and while they recover from knockouts to see how the levels of NSE change over time. These types of biomarkers could be useful in sports medicine to help decide when an athlete should abstain from training and competition. But the method must first be evaluated further”.

These researchers had previously shown that amateur boxing leads to increased levels of brain damage markers in spinal fluid.

Source: http://www.sahlgrenska.gu.se/english/

August 24, 2009

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