Friday, February 29, 2008
Dr. Nitish Priyadarshi
Carbon dioxide is probably the most important of the greenhouse gases as it accounts for the largest proportion of the 'trace gases' and is currently responsible for 60% of the 'enhanced greenhouse effect'. It is thought that it's been in the atmosphere for over 4 billion of the Earth's 4.6 billion year geological history and in much larger proportions (up to 80%) than today.
Most of the carbon dioxide was removed from the atmosphere as early organisms evolved photosynthesis. This locked away carbon dioxide as carbonate minerals, oil shale and coal, and petroleum in the Earth's crust when the organisms died. This left 0.03% in the atmosphere today.
The natural carbon dioxide cycle:
Atmospheric carbon dioxide comes from a number of natural sources, mainly the decay of plants, volcanic eruptions and as a waste product of animal respiration.
It is removed from the atmosphere by photosynthesis in plants and by dissolving in water, especially on the surface of oceans.
Carbon dioxide stays in the atmosphere for approximately 100 years.
The amount of carbon dioxide taken out of the atmosphere by plants is almost perfectly balanced with the amount put back into the atmosphere by respiration and decay. Small changes as a result of human activities can have a large impact on this delicate balance.
The impact of human activities:
Over the past three centuries, concentration of carbon dioxide is reported to be increasing in the Earth’s atmosphere, due to human activities like the burning of fossil fuels and deforestation that cause the release of carbon dioxide into the atmosphere.
Burning fossil fuels releases the carbon dioxide stored millions of years ago. We use fossil fuels to run vehicles (petrol, diesel and kerosene), heat homes, businesses and power factories. Deforestation releases the carbon stored in trees and also results in less carbon dioxide being removed from the atmosphere.
From the early 1700s, carbon dioxide has increased from 280 ppm to 360 ppm in 1990. many studies suggest that higher concentration of carbon dioxide in the atmosphere will enhance the green house effect making the earth warmer. It is likely that the thinning of ice masses, and retreat of glaciers of Himalaya and trans-Himalayan region during the last 150 years or so is an affect of such warming.
Most computer models suggest that the globe will warm up 1.5 degree centigrade to 4.5 degree centigrade if carbon dioxide reaches the predicted level of 600 ppm by the 2050. although this may be largely true, there are other possible mechanisms that could act in the opposite direction. For instance the sulphate aerosols-the tiny bit of dust that are also added to the atmosphere when fossil fuels are burned by human activity, may cool the climate. The aerosols reflect away the sun’s radiation. Thus, they partially counter the warming that may be caused by the greenhouse gases. However, the degree to which these emissions might reduce the impact of greenhouse gases is not yet fully understood.
Studies suggest that an increase in ocean temperatures associated with global warming could lead to increase in emission of dimethyl sulfide by photosynthesis. This would in turn increase the concentration of sulphate aerosols in the marine boundary layer causing an increase in the number of cloud drops. The net result of the cloud will be to cool the Earth to offset the warming by the greenhouse effect.
Sulphate aerosol is a type of solid compound commonly found in the atmosphere. Sulphate particles play an important role in reflecting, absorbing, and scattering incoming solar energy. The source of these compounds is both natural and man-made. Most of the man-made particles come from combustion of fossil fuels.
It is therefore possible that increased levels of trace gases in the atmosphere would lead to cooling of the Earth rather than to a net heating.
• Mathur, U.B. 2005. Quaternary Geology Indian Perspective. Geological Society of India, Bangalore.
Tuesday, February 26, 2008
QUATERNARY CLIMATE CHANGE
Dr. Nitish Priyadarshi
In recent years, the global climate has been exhibiting signs of change that can neither be overlooked nor fully explained in the terms of natural climate variations. In this context, scientists, environmentalists, policy makers and others interested in the subject of climate change have been posing several fundamental questions like:
· Is the earth’s climate really changing?
· How has the climate changed in the past?
· Why does climate change?
· How much is the human influence on climate?
· What will the future climate be like?
· What are the likely impacts of climate change?
These questions are not new, but we are in a much better position to answer them today than ever before. We have come a long way towards a clearer understanding about connections among the different components of the climate system, the nature of the feedback mechanisms and the natural dynamics of the natural system.
The climate system is subjected to external forcings like the incoming solar radiation, and is also influenced by internal interactions among its five components viz., the atmosphere, hydrosphere, cryosphere, lithosphere and the biosphere. In the past, scientists have treated them individually and it is only now that the linkages among these components are being brought into proper perspective.
The term Quaternary is derived from the Latin word “quatern” and refer to the most recent period of the Earth’s history covering a span of the past ca 1.77 m.y. (million years) and extends upto the present day. The Quaternary period is subdivided into Pleistocene and Holocene epochs. Originally the term Pleistocene was proposed for the epoch which comprises 70% of the species that are still living. The term Holocene was introduced for the part of the Quaternary that contains only species that are still living.
During the short interval of the Quaternary, some very important events took place, which are of great consequence for us today. It is characterized by dramatic climatic changes, including repeated glacial and interglacial events.
Climate change is a dynamic phenomenon. Climate is continuously changing, sometimes at a slow pace, sometimes faster. In the geological past, the earth was probably warmer for most of the time than at present, with little or no polar ice. However at frequent intervals, extensive glaciations occurred in the past. The last glaciation, prior to the Quaternary ice ages, took place during late Carboniferous to basal Permian ca 300 m.y. ago.
The world began to cool rapidly in late Tertiary about 40 m.y. ago. By about 2.6 m.y. ago, the world had cooled so much that ice sheets began to form in northern Canada and Scandinavia. In the Indian sub-continent, glaciers spread far and wide over Potwar, Kashmir, Kangra, and in Ladakh-Tibet regions. From this time onwards, climate changes were more dramatic than during earlier geological times. During certain time intervals of Quaternary, temperatures dropped too low forming large ice sheets. However at other times the climate was warm, comparable to that of today, or even warmer.
Early only four glacial periods, of varying duration and severity, with the intervening interglacial periods, during which the climate became warmer, were recognized during the quaternary. Now it is certain that the number of such episodes exceeded four.
Another important feature of Quaternary was intense dune-building activity from time to time. In the deserts of Sahara (Africa), India, the Middle East and Australia, the time of peak aridity and maximum dune activity was during the last glacial period about 20 k.y. to 12 k.y. ago. One estimate is that the tropical arid zones were five times larger during the times of peak glaciation. Sea level was lower at these times (consequently exposing large continental shelf area to erosion), water was colder, and tropical cyclones were less extensive, resulting in decreased rainfall.
During glaciations, lower sea-level brought about another important geological effect on the land. The rivers started down-cutting their valleys and sedimentation pattern changed. There were many other similar changes consequent to the climate changes during Quaternary, like lake-level change and lowering of river discharge because of changes in precipitation.
Indian Monsoon during Holocene:
From palaeoclimate studies of the Indian monsoon, it is postulated that four monsoon maxima occurred during the last 150,000 years in association with solar radiation changes.
Pollen density sequences from lake beds of northwestern India and lake levels suggest that the monsoon were weak before 18,000 years B.P., that a warm and humid climate existed between 10,000 and 5,000 years B.P. or early Holocene, and that trend towards aridity set in around 3,500 years B.P. Tibetan ice core analysis indicate prolonged drought during the 18th century A.D. Extensive sampling of tree rings over western Himalayas has shown signatures both of the little Ice Age and the Medieval Warm Period. The northern limit of the monsoon reaching the desert margins has undergone wide fluctuations in the past, coinciding with the rise and decline of civilization such as the Indus Valley Civilization (2300-1700 B.C.), ‘Painted Grayware’ Culture (700-300 B.C.) and the Rangamahal Culture (100-200 A.D.).
Until recently, human activities have been considered to be an insignificant force in natural dynamics. Today, their impact has begun to match, and even exceed, that of natural processes. Fossil fuel reserves that were generated over a period of several hundred million years are now on the verge of depletion. As much as 50% of the land surface has been transformed by direct human action, with significant consequences for biodiversity, nutrient cycling, soil structure, biology and climate.
It appears that we are in a process of transition from the Holocene into a new epoch, for which the Nobel Prize winner, Paul Crutzen, and other scientists have coined the term “Anthropocene”.
- Quaternary Geology Indian Perspective (2005) by U.B. Mathur. Geological Society of India.
- The Indian Monsoon as a component of the climate system during the Holocene,(2006) by R.R. Kelkar, In journal of Geological Society of India, Vol.68, no.3.
Thursday, February 21, 2008
What is Hydrazine?
Dr. Nitish Priyadarshi
U.S officials say a missile launched from a Navy ship in the Pacific successfully hit a U.S. spy satellite more than 200 kilometers above the Earth today on 21Feb. 2008. The dying satellite stopped communicating with controllers on Earth shortly after it was launched 14 months ago, and it began to slowly fall. The shoot-down was intended to destroy a tank aboard the craft holding 450 kilograms of a toxic fuel called hydrazine. Officials said the fuel posed a danger to humans if the tank survived re-entry.
Hydrazine is the chemical compound with the formula (NH2)2. It has an ammonia-like odor, and is derived from ammonia, but its physical properties are more similar to those of water. Hydrazine is usually handled as 60% aqueous solution. It is mainly used in as a blowing agent in preparing polymer foams, but significant applications also include its uses as a precursor to polymerization catalysts and pharmaceuticals. It is used in rocket fuels
Hydrazine is used in many processes including: production of spandex fibers, as a polymerization catalyst; in fuel cells, solder fluxes; and photographic developers, as a chain extender in urethane polymerizations, and heat stabilizers.
Hydrazine a toxic, flammable caustic liquid and a strong reducing agent. Its odour is similar that of ammonia, though less strong. It is slightly soluble in ammonia and methyl-amine. It is soluble in water, methanol, ethanol, UDMH, and ethylenediamine. Hydrazine is manufactured by the Raschig process, which involves the oxidation of ammonia to chloramine, either indirectly with aqueous sodium hypochlorite or directly with chlorine, and subsequent reaction of chloramine with excess ammonia. Raw materials include caustic, ammonia, and chlorine; these are high-tonnage, heavy chemicals.
Hydrazine is highly toxic and dangerously unstable, especially in the anhydrous form. According to the U.S. Environmental Protection Agency:
Symptoms of acute (short-term) exposure to high levels of hydrazine may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, coma in humans. Acute exposure can also damage the liver, kidneys, and central nervous system. The liquid is corrosive and may produce dermatitis from skin contact in humans and animals. Effects to the lungs, liver, spleen, and thyroid have been reported in animals chronically exposed to hydrazine via inhalation. Increased incidences of lung, nasal cavity, and liver tumors have been observed in rodents exposed to hydrazine
Dr. Nitish Priyadarshi
Ruby is an excellent stone for energy. Imparting vigor to life, it energizes and balances but may sometimes over stimulate in delicate or irritable people. Ruby encourages passion for life but never in a self-destructive way. It improves motivation and setting of realistic goals.
Most rubies come from Sri Lanka, but the best quality stones are mined in Burma. The rich red wine colour of these jewels is enhanced by electric light so it is always advisable to examine them in natural day light before purchase.
Because of its colour, the ruby has always been associated with healing diseases of the blood. Eastern mythology calls it ‘a drop of blood from Mother Earth’s heart’.
Red colour of ruby is due to Cr2 03 present in solid solution. In low concentration colour is pale, inclining to pink. With a concentration between 1% and 4%, colour deepens. Some amount of iron is generally present in ruby, which reduces the richness of red shale. With a higher amount of iron ruby turns brownish. Chromium rich rubies impart red fluorescence. Iron rich rubies may not fluorescence at all.
Different crystals now a days are used in medical practices. They are piezoelectric, which means that electricity, and sometimes light, is produced by compression. This property is harnessed in ultrasound machines, which use a piezoelectric crystal to produce a sound wave. Sound is now being applied at the leading edge of the surgery. A tightly focused beam of ultrasound can cauterize wounds deep within the body and blast tumors without the need for invasive procedures.
Crystals were created as the earth formed and they have continued to metamorphose as the planet itself has changed. Crystals are the earth’s DNA, a chemical imprint for evolution. They are the miniature storehouses, containing the records of the development of the earth over million of years.
Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only diamond is harder, with a Mohs 10.0 by definition.
All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form, with heat treatment being the most common practice. However, rubies that are completely untreated are still of excellent quality and command a large premium.
Its color varies from deep cochineal to pale rose red, in some cases inclining to purple, the most valued tint being that know to experts as pigeon’s blood color. On exposure to a high temperature the ruby becomes green, but regains its original color on cooling-a behavior which is consistent with the supposition that the stone owes its color to the presence of oxide of chromium, and indeed in artificial rubies the required tint is always obtained by the use of some compound of chromium.
Ruby stimulates the heart chakra and balances the heart. It promotes positive dreams and clear visualization, and stimulates the pineal gland.
Physically Ruby overcomes exhaustion and lethargy and imparts potency and vigor. Conversely, it calms hyperactivity.
Ruby detoxifies the body, blood and lymph, and treats fever, infectious disease, and restricted blood flow. It stimulates the adrenals, kidneys, reproductive organs and spleen.
In Ancient Greece it was thought that rubies and other crystals could be either male or female. Stones with stronger colours were said to be male while paler varieties of the same crystal indicated that they were female. The ruby is one of several stones said to foretell death. If its colour paled or changed to black, the wearer’s life was in danger.
2. The Crystal Bible by Judy Hall
3. The healing power of crystals by Cass and Janie Jackson.
4. Gems and Gem Industry in India, by R.V. Karanth, Geological society of India.
Wednesday, February 13, 2008
Dr. Nitish Priyadarshi
Nasa’s spirit is seen exploring bright, loose material on the Mars. According to NASA it is a most colorful deposits. It has a powdery and cloddy texture and exhibits a high abundance of salt. Spirit analyzed the bright, yellowish exposures. Scientists hypothesized and then confirmed that these materials have a salty chemistry dominated by iron-bearing sulfates. These salts may record the past presence of water, as they are mostly easily mobilized and concentrated in liquid solution.
But if you see the other side of this concept. This deposit or structure very much resembles abandoned open mines similar to coal mines or Bauxite mines or Iron ore mines on our Earth. The white deposit very much resembles to the clay deposits in coal mines area. Clays are generally treated as mine wastes. But due to lack of evidence of vegetation both at present and past on Mars, formation of coal deposit can be questioned. If it is lost Bauxite mines the white deposits may be clay mineral Kaolinite. The photographs clearly indicate that this is one of the abandoned mines after the exploitation of the minerals. White matter also resembles with Borax. Borax occurs in the waters of saline lakes and in salt pans in desert regions. In both cases derived from solar evaporation of saline waters.
If you see the outer boundary or curve in the photograph it is very similar to open mines here on the Earth. In other words it is more man made than natural.
Mining may have been done either by the lost civilization of Mars or by the other civilization of other planets and left it with this structure after exploiting the minerals.
Dr. Nitish Priyadarshi
Wednesday, February 6, 2008
What is Radiation?
Atoms, the building blocks of the universe, are held together by natural forces. Tremendous amounts of energy are stored in the center of the atom, the nucleus. Although most nuclei are stable, some are unstable. Unstable nuclei, made up of combinations of protons and neutrons that cannot maintain balance, spontaneously change to reach a more stable form through a process known as radioactive decay. During the decay process (that is, the atom changing to reach a more stable form), some of the atom’s natural energy is released. The released energy, known as radiation, can be in the form of particles or waves.
The unstable atoms that undergo radioactive decay are known as radioisotopes or radionuclides. Some unstable isotopes of radium, radon, uranium, and thorium, exist naturally in the Earth. Other radionuclides are continually being made naturally (by cosmic rays) or by human activities, such as the splitting of atoms in a nuclear reactor.
Terrestrial sources contribute about 84 per cent of the total radiation from natural sources to which an individual is exposed. This dose is about 2 mSv per year and includes overall (indoor as well as outdoor) radiation dose. It is an accumulated effect arising from a number of materials around such as rocks, soil, water, air, food and even from within the human body. The sources of terrestrial radiation are certain elements which are radioactive and some radionuclides created at the time of formation of the earth. These radionuclides, while giving out radiation, decay in the form of different chains to result in products known as ‘daughter elements’. At least, there are four well-known radioactive series or chains of elements, one starting with uranium-238, a second with thorium-232, a third with uranium-235 and fourth with plutonium-241.
The earth’s crust contains a very large number of radioactive substances in different geographical regions of the world. A survey of twenty three countries having more than half of the world’s population has shown that exposure to such external radiation is nearly the same. These studies suggested that 95 per cent of the world’s population gets an average annual dose of 0.4 mSv due to outdoor terrestrial radiation. Such areas are in Brazil, Sweden, France, and India. Guarapari, Meaipe, and Pocos de Caldas in Brazil, and coastal areas of Kerala and Tamil Nadu in India have thorium-rich monazite sands which provide much higher doses than the average mentioned above. Similarly, there are active regions rich in granite, in France, with a high Uranium and Thorium content and alum shale, in Sweden, with high uranium and radium concentrations which also provide larger doses of radiation.
Uranium may be found in:
Thorium in the environment
Thorium is surprisingly abundant in the Earth's crust, being almost as abundant as lead and three times more abundant than uranium. It is found in small amounts in most rocks and soils. Granite contains up to 80 ppm of thorium. Because thorium oxide is highly insoluble, very little of this element circulates through the environment. Thorium occurs naturally as the minerals thorite, uranothorite, thorianite, it is a major component of monazite and it is present in significant amounts in the minerals zircon, titanite, gadolinite and betafite
What is radium?
Radium is a naturally occurring silvery-white radioactive metal that can exist in several forms called isotopes. Radium is formed when uranium and thorium break down in the environment. Uranium and thorium are found in small amounts in most rocks and soil. Two of the main radium isotopes found in the environment are radium-226 and radium-228.
What happens to radium when it enters the environment?
· Radium is constantly being produced by the radioactive decay of uranium and thorium.
· Radium is present at very low levels in rocks and soil and may strongly attach to those materials.
· Radium may also be found in air.
· High concentrations are found in water in some areas of the country.
· Uranium mining results in higher levels of radium in water near uranium mines.
· Radium in the soil may be absorbed by plants.
· It may concentrate in fish and other aquatic organisms.
It is worthwhile to mention here that, in general, igneous rocks such as granites are more radioactive than the sedimentary rocks. However, highly radioactive shales and phosphates rocks are the exceptions in the category of sedimentary rocks.
We are affected by terrestrial radiation even inside our house. The single most important and all-pervasive source of internal terrestrial radiation in some countries is the odourless gas, radon. It enters buildings mostly from the ground by the process of soil convection or soil diffusion through the underlying or surrounding soils. If the ventilation is inadequate, its concentration in the house may be hundred or even thousand times higher than outside.
Radon is a terrestrial source of radiation that is of particular concern because, although on average it is very rare, this intensely radioactive element can be found in high concentrations in many areas of the world, where it represents a significant health hazard. Radon is a decay product of uranium, which is relatively common in the earth's crust, but generally concentrated in ore-bearing rocks scattered around the worldThe widespread construction of well insulated and sealed homes in the northern industrialized world has led to radon becoming the primary source of background radiation in some localities in northern North America and Europe.
Building materials, such as stone and concrete release higher doses of radiation because of higher concentrations of uranium, thorium and their daughter nuclides, mainly radon gas. In addition to this, large groups of population also get high doses of radiation through drinking water, containing high concentrations of the elements, radium-226 and radon-222. Some of the springs in Austria, Iran, Italy and India as well and several wells in the USA (particularly in Texas and Argonne areas) have a high radioactive content.
Among the internal sources of radiation are potassium-40, lead-210 and polonium-210 which enter our body through our food. Besides these, very minute quantities of uranium, radium, carbon-14 and tritium are already present in our body. While the quantity of potassium is controlled and remains the same in the body, the levels of lead-210 and polonium-210 are affected through the dietary intake. For example, the concentration of these nuclides in sea-food is five times higher in Japan than that in the USA. Similarly, in the northern hemisphere, people who depend for their food mainly on reindeer or caribou meat, show a significantly higher intake of these radionuclides. This is because these animals graze on lichens which are concentrated with lead and polonium. These two radionuclides are also found in tobacco. Among other foods, the radium content in nuts and cereals is higher than that in milk, or meat.
Potassium-40 is a naturally occurring nucleid. It was formed together with the other elements during the creation of the earth. Due to its long half life of 1.28 billion years it is still present on earth. K-40 is the only radioactive isotope of potassium and is present in an amount of 0.0119% in this natural element. Potassium as well as K-40 are present in most terrestrial and biological substances, for ex. it is a macronutrient for plants. The body of a 70 kg person contains ca. 140 g of potassium and thus an activity of 4000 Bq K-40. Due to its presence in almost all foods this nucleid accounts for the greatest proportion of the naturally occurring radiation load through ingestion among people.
Potassium 40 is found in:
· potassium feldspar (orthoclase)
· glauconite (greensand; found in some sedimentary rocks; rare)
What Is the Primary Health Effect?
Potassium-40 can present both an external and an internal health hazard. While in the body, potassium-40 poses a health hazard from both the beta particles and gamma rays. Potassium-40 behaves the same as ordinary potassium, both in the environment and within the human body – it is an essential element for both. Hence, what is taken in is readily absorbed into the bloodstream and distributed throughout the body, with homeostatic controls regulating how much is retained or cleared. The health hazard of potassium-40 is associated with cell damage caused by the ionizing radiation that results from radioactive decay, with the general potential for subsequent cancer induction.
Thus it may be concluded that the radioactive content entering into our body depends upon the type of food we take and the environment in which it is grown.
Jain, H.C. 1994. Radiation and Man. National Book Trust, India.
Wagner, T. 1994. In our backyard. John Wiley & Sons,Inc. New York.