हर इन्सान में कहीं न कहीं होता तो है ही संकोच,
दूसरों को ही वोह खुशी देना चाहता है हर रोज़ ,
छिपाता है दूसरों से और सह लेता है ख़ुद दुःख,
बदले में जो भी मिले दुःख या फ़िर सुख।
वह इंसान जो भी हो , होता तो है ही महान,
दूसरों का सोचने वाला वह कर देता है कीर्तिमान।
वह ख़ुद नहीं जानता कितनी तकलीफें आएँगी और,
मदद तो करना ही है सबकी ,चाहे हो इंसान या फ़िर हैवान।
माँ की ममता में भी संकोच छिपा रहता है,
दर्द होता है यदि पुत्र कुछ सहता है।
ममता भी महानता का ही एक रूप लगती है,
यह महसूस करके पुत्र का भी अश्क निकल बहता है।
वह अश्क में क्या क्या छिपा रहता है,
यह तो सिर्फ़ वह पुत्र ही जानता है,
दया,स्नेह,आदि से भरपूर वो अश्क,
जब निकलता है तो कभी नहीं ठहेरता है।
पुत्र की स्थिती देखकर पिता उसे सहानुभूति देता है,
पुत्र सहानुभूति को भो माँ की ममता समझ लेता है,
पिता ,पुत्र और माँ का यह अनूठा रिश्ता,
भगवान् ही तो बाँध कर देता है.
Saturday, October 24, 2009
Monday, June 15, 2009
Intezaar !! This poem I wrote on 20th may 2007 longing for the result!!
इंतज़ार
खोया हुआ बैठे बैठे करता हूँ मैं इंतज़ार,
बोर होता हूँ लगता है मुझे सबकुछ बेकार,
लगता है वक़्त थम सा गया है सदा के लिए,
बताओ भाई क्या समय का भी होता है व्यापार?
एक क्षण बिताना भी मुश्किल सा हो गया है,
अपने आप को ऐसे देखकर मन क्रोधित सा हो गया है,
कहाँ जाऊं , क्या करूँ, किस्से बात करूँ मैं?
इस दिशा को देखकर मन विचलित सा हो गया है।
किताबों की टेबल और कुर्सी सूनी सी हो गई है,
चेहरे पर इंतज़ार और मन में मासूमियत सी हो गई है,
PET का समय आएगा जब,
तब कहूँगा , उन किताबों की फ़िर से ज़रूरत सी हो गई है।
समय तो चलता है अपनी गति से हर बार,
विश्वास है की वो समय भी आएगा एक बार,
खुशी या ग़म उस समय पता चलेगा,
जब आएगी जीत या फ़िर हार की पुकार।
क्या मालूम आगे क्या होना है?
हँसना है या फ़िर रोना है?
जो होता है अच्छे के लिए होता है,
यह मानके मन को अपने दतोलना है,
महनत का फल अवश्य ही मिलना है ,
तो फ़िर किस बात पर रोना है??
खोया हुआ बैठे बैठे करता हूँ मैं इंतज़ार,
बोर होता हूँ लगता है मुझे सबकुछ बेकार,
लगता है वक़्त थम सा गया है सदा के लिए,
बताओ भाई क्या समय का भी होता है व्यापार?
एक क्षण बिताना भी मुश्किल सा हो गया है,
अपने आप को ऐसे देखकर मन क्रोधित सा हो गया है,
कहाँ जाऊं , क्या करूँ, किस्से बात करूँ मैं?
इस दिशा को देखकर मन विचलित सा हो गया है।
किताबों की टेबल और कुर्सी सूनी सी हो गई है,
चेहरे पर इंतज़ार और मन में मासूमियत सी हो गई है,
PET का समय आएगा जब,
तब कहूँगा , उन किताबों की फ़िर से ज़रूरत सी हो गई है।
समय तो चलता है अपनी गति से हर बार,
विश्वास है की वो समय भी आएगा एक बार,
खुशी या ग़म उस समय पता चलेगा,
जब आएगी जीत या फ़िर हार की पुकार।
क्या मालूम आगे क्या होना है?
हँसना है या फ़िर रोना है?
जो होता है अच्छे के लिए होता है,
यह मानके मन को अपने दतोलना है,
महनत का फल अवश्य ही मिलना है ,
तो फ़िर किस बात पर रोना है??
Sunday, June 7, 2009
Reality........
The world is here, to which i m bound
Nothing seems real, noone's around.
Whatever i feel, whatever i say,
No answers returned, all's made of clay.
When i needed love, was loaded with a cold heart,
When I needed a friend, still it's too hard.
When I needed happiness, to get from this world,
All were impassive, as if they didn't heard.
Was it too much to ask and my expectations high,
Or was it not the world, I dreamed to live by,
Or is it just a dream, reality is something else,
Or is this the REALITY?????
Thursday, May 21, 2009
Aerogel
Aerogel is a solid-state material with the lowest known density[citation needed]; it is derived from gel in which the liquid component of the gel has been replaced with gas. The result is an extremely low-density solid with several remarkable properties, most notably its effectiveness as a thermal insulator. It is nicknamed frozen smoke, solid smoke or blue smoke due to its translucent nature and the way light scatters in the material; however, it feels like expanded polystyrene (styrofoam) to the touch.
The flower kept on Aerogel doesn't get even a bit hotter on subjecting to a flame of 1273K from the other side.
Aerogel was first created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid inside of a jam jar with gas without causing shrinkage.
Aerogels are produced by extracting the liquid component of a gel through supercritical drying. This allows the liquid to be slowly drawn off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation. The first aerogels were produced from silica gels. Kistler's later work involved aerogels based on alumina, chromia and tin oxide. Carbon aerogels were first developed in the late 1980s.
Contents
■1 Properties
■2 Types
■2.1 Silica aerogels
■2.2 Carbon aerogels
■2.3 Alumina aerogels
■2.4 Other aerogels
■3 Uses
■4 Production
■5 Safety
Properties
A demonstration of aerogel's insulation propertiesTo the touch, aerogels feel like a light but rigid foam, something between Styrofoam and the green floral foam used for arranging flowers. Despite what their name may suggest, aerogels are dry materials and do not resemble a gel in their physical properties; the name comes from the fact that they are derived from gels. Pressing softly on an aerogel typically does not leave a mark; pressing more firmly will leave a permanent dimple. Pressing firmly enough will cause a catastrophic breakdown in the sparse structure, causing it to shatter like glass—a property known as friability. Despite the fact that it is prone to shattering, it is very strong structurally. Its impressive load bearing abilities are due to the dendritic microstructure, in which spherical particles of average size 2-5 nm are fused together into clusters. These clusters form a three-dimensional highly porous structure of almost fractal chains, with pores smaller than 100 nm. The average size and density of the pores can be controlled during the manufacturing process.
Aerogels are good thermal insulators because they almost nullify the three methods of heat transfer (convection, conduction and radiation). They are good convective inhibitors because air cannot circulate throughout the lattice. Silica aerogel is an especially good conductive insulator because silica is a poor conductor of heat—a metallic aerogel, on the other hand, would be a less effective insulator. Carbon aerogel is a good radiative insulator because carbon absorbs the infrared radiation that transfers heat at standard temperatures. The most insulative aerogel is silica aerogel with carbon added to it.
Due to its hygroscopic nature, aerogel feels dry and acts as a strong desiccant. Persons handling aerogel for extended periods of time should wear gloves to prevent the appearance of dry brittle spots on their hands.
Since it is 99.8% air, it appears semi-transparent. The color it does have is due to Rayleigh scattering of the shorter wavelengths of visible light by the nanosized dendritic structure. This causes it to appear smoky blue against dark backgrounds and yellowish against bright backgrounds.
Aerogels by themselves are hydrophilic, but chemical treatment can make them hydrophobic. If they absorb moisture they usually suffer a structural change, such as contraction, and deteriorate, but degradation can be prevented by making them hydrophobic. Aerogels with hydrophobic interiors are less susceptible to degradation than aerogels with only an outer hydrophobic layer, even if a crack penetrates the surface. Hydrophobic treatment facilitates processing because it allows the use of a water jet cutter.
Types
Silica aerogels
Aerogel produced at Florida State University by Elliot Schwartz and Robert PalmerSilica aerogel is the most common type of aerogel and the most extensively studied and used. It is a silica-based substance, derived from silica gel. The world's lowest-density solid is a silica nanofoam at 1 mg/cm3, which is the evacuated version of the record-aerogel of 1.9 mg/cm3. The density of air is 1.2 mg/cm3.
Silica aerogel strongly absorbs infrared radiation. It allows the construction of materials that let light into buildings but trap heat for solar heating.
It has remarkable thermal insulative properties, having an extremely low thermal conductivity: from 0.03 W/m·K down to 0.004 W/m·K,[5] which correspond to R-values of 14 to 105 for 3.5 inch thickness. For comparison, typical wall insulation is 13 for 3.5 inch thickness. Its melting point is 1,473 K (1,200 °C or 2,192 °F).
Silica aerogel holds 15 entries[citation needed] in Guinness World Records for material properties, including best insulator and lowest-density solid.
Carbon aerogels
Carbon aerogels are composed of particles with sizes in the nanometer range, covalently bonded together. They have very high porosity (over 50%, with pore diameter under 100 nm) and surface areas ranging between 400–1000 m²/g. They are often manufactured as composite paper: non-woven paper made of carbon fibers, impregnated with resorcinol-formaldehyde aerogel, and pyrolyzed. Depending on the density, carbon aerogels may be electrically conductive, making composite aerogel paper useful for electrodes in capacitors or deionization electrodes. Due to their extremely high surface area, carbon aerogels are used to create supercapacitors, with values ranging up to thousands of farads based on a capacitance of 104 F/g and 77 F/cm³. Carbon aerogels are also extremely "black" in the infrared spectrum, reflecting only 0.3% of radiation between 250 nm and 14.3 µm, making them efficient for solar energy collectors.
The term "aerogel" has been incorrectly used to describe airy masses of carbon nanotubes produced through certain chemical vapor deposition techniques—such materials can be spun into fibers with strength greater than Kevlar, and unique electrical properties. These materials are not aerogels, however, since they do not have a monolithic internal structure and do not have the regular pore structure characteristic of aerogels.
Alumina aerogels
Aerogels made with aluminium oxide are known as alumina aerogels. These aerogels are used as catalysts, especially when "metal-doped" with another metal. Nickel-alumina aerogel is the most common combination. Alumina aerogels are also examined by NASA for capturing of hypervelocity particles; a formulation doped with gadolinium and terbium could fluoresce at the particle impact site, with amount of fluorescence dependent on impact velocity.
Other aerogels
SEAgel is a material similar to organic aerogel, made of agar.
Chalcogels are a type of aerogel made of chalcogens (the column of elements on the periodic table beginning with oxygen) such as sulfur, selenium, and other elements. Research is ongoing, and metals less expensive than platinum have also been used in its creation.
Aerogels made of Cadmium selenide quantum dots in a porous 3-D network have recently been developed for use in the semiconductor industry.
Uses
The Stardust dust collector with aerogel blocks. (NASA)There are a variety of tasks for which aerogels are used.
■Commercially, aerogels have been used in granular form to add insulation to skylights.
■Transparent silica aerogel would be very suitable as a thermal insulation material for windows, significantly limiting thermal losses of buildings. One research team (http://zerogaerogel.com) has shown that producing aerogel in a weightless environment can produce particles with a more uniform size and reduce the Rayleigh scattering effect in silica aerogel, thus making the aerogel less blue and more transparent.
■Its high surface area leads to many applications, such as a chemical absorber for cleaning up spills (see adsorption). This feature also gives it great potential as a catalyst or a catalyst carrier.
■Aerogel particles are also used as thickening agents in some paints and cosmetics.
■Aerogels are being tested for use in targets for the National Ignition Facility.
■Aerogel performance may be augmented for a specific application by the addition of dopants, reinforcing structures, and hybridizing compounds. Using this approach, the breadth of applications for the material class may be greatly increased.
■Commercial manufacture of aerogel 'blankets' began around the year 2000. An aerogel blanket is a composite of silica aerogel and fibrous reinforcement that turns the brittle aerogel into a durable, flexible material. The mechanical and thermal properties of the product may be varied based upon the choice of reinforcing fibers, the aerogel matrix, and opacification additives included in the composite.
■NASA used aerogel to trap space dust particles aboard the Stardust spacecraft. The particles vaporize on impact with solids and pass through gases, but can be trapped in aerogels. NASA also used aerogel for thermal insulation of the Mars Rover and space suits.
■The US Navy is evaluating aerogel undergarments as passive thermal protection for divers.
■Aerogels are also used in particle physics as radiators in Cherenkov effect detectors. ACC system of the Belle detector, used in the Belle Experiment at KEKB, is a recent example of such use. The suitability of aerogels is determined by their low index of refraction, filling the gap between gases and liquids, and their transparency and solid state, making them easier to use than cryogenic liquids or compressed gases. Their low mass is also advantageous for space missions.
■Resorcinol-formaldehyde aerogels (polymers chemically similar to phenol formaldehyde resins) are mostly used as precursors for manufacture of carbon aerogels, or when an organic insulator with large surface is desired. They come as high-density material, with surface area about 600 m²/g.
■The first residential use of aerogel as an insulator is in the Georgia Institute of Technology's Solar Decathlon House where it is used as an insulator in the semi-transparent roof.
■Metal-aerogel nanocomposites can be prepared by impregnating the hydrogel with solution containing ions of the suitable noble or transition metals. The impregnated hydrogel is then irradiated with gamma rays, leading to precipitation of nanoparticles of the metal. Such composites can be used as catalysts, sensors, electromagnetic shielding, and in waste disposal. A prospective use of platinum-on-carbon catalysts is in fuel cells.
■Aerogel can be used as a drug delivery system due to its biocompatibility. Due to its high surface area and porous structure, drugs can be adsorbed from supercritical CO2. The release rate of the drugs can be tailored based on the properties of aerogel.
■Carbon aerogels are used in the construction of small electrochemical double layer supercapacitors. Due to the high surface area of the aerogel, these capacitors can be 1/2000th to 1/5000th the size of similarly rated electrolytic capacitors.Aerogel supercapacitors can have a very low impedance compared to normal supercapacitors and can absorb or produce very high peak currents. At present, such capacitors are polarity-sensitive and need to be wired in series if a working voltage of greater than about 2.75V is needed.
■Dunlop has recently incorporated aerogel into the mold of its new series of tennis racquets, and has previously used it in squash racquets.
■Chalcogels have shown promise in absorbing the heavy metal pollutants mercury, lead and cadmium from water.
■Aerogel is used to introduce disorder into superfluid Helium-3.
Production
Silica aerogel is made by drying a hydrogel composed of colloidal silica in an extreme environment. Specifically, the process starts with a liquid alcohol like ethanol which is mixed with a silicon alkoxide precursor to form a silicon dioxide sol gel (silica gel). Then, through a process called supercritical drying, the alcohol is removed from the gel. This is typically done by exchanging the ethanol for liquid acetone, allowing a better miscibility gradient, and then onto liquid carbon dioxide and then bringing the carbon dioxide above its critical point. A variant on this process involves the direct injection of supercritical carbon dioxide into the pressure vessel containing the aerogel. The end result removes all liquid from the gel and replaces it with gas, without allowing the gel structure to collapse or lose volume.
Aerogel composites have been made using a variety of continuous and discontinuous reinforcements. The high aspect ratio of fibers such as fiberglass have been used to reinforce aerogel composites with significantly improved mechanical properties.
Resorcinol-formaldehyde aerogel (RF aerogel) is made in a way similar to production of silica aerogel.
Carbon aerogel is made from a resorcinol-formaldehyde aerogel by its pyrolysis in inert gas atmosphere, leaving a matrix of carbon. It is commercially available as solid shapes, powders, or composite paper.
Safety
Silica-based aerogels are not known to be carcinogenic or toxic. However, they are a mechanical irritant to the eyes, skin, respiratory tract and digestive system. They also can induce dryness of the skin, eyes and mucous membranes. Therefore, it is recommended that protective gear including gloves and eye goggles be worn whenever handling aerogels.[20]
However, safety depends on the material from which the aerogel is made – it will be carcinogenic or toxic if the solid component has such characteristics.
The flower kept on Aerogel doesn't get even a bit hotter on subjecting to a flame of 1273K from the other side. Aerogel was first created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid inside of a jam jar with gas without causing shrinkage.
Aerogels are produced by extracting the liquid component of a gel through supercritical drying. This allows the liquid to be slowly drawn off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation. The first aerogels were produced from silica gels. Kistler's later work involved aerogels based on alumina, chromia and tin oxide. Carbon aerogels were first developed in the late 1980s.
Contents
■1 Properties
■2 Types
■2.1 Silica aerogels
■2.2 Carbon aerogels
■2.3 Alumina aerogels
■2.4 Other aerogels
■3 Uses
■4 Production
■5 Safety
Properties
A demonstration of aerogel's insulation propertiesTo the touch, aerogels feel like a light but rigid foam, something between Styrofoam and the green floral foam used for arranging flowers. Despite what their name may suggest, aerogels are dry materials and do not resemble a gel in their physical properties; the name comes from the fact that they are derived from gels. Pressing softly on an aerogel typically does not leave a mark; pressing more firmly will leave a permanent dimple. Pressing firmly enough will cause a catastrophic breakdown in the sparse structure, causing it to shatter like glass—a property known as friability. Despite the fact that it is prone to shattering, it is very strong structurally. Its impressive load bearing abilities are due to the dendritic microstructure, in which spherical particles of average size 2-5 nm are fused together into clusters. These clusters form a three-dimensional highly porous structure of almost fractal chains, with pores smaller than 100 nm. The average size and density of the pores can be controlled during the manufacturing process.
Aerogels are good thermal insulators because they almost nullify the three methods of heat transfer (convection, conduction and radiation). They are good convective inhibitors because air cannot circulate throughout the lattice. Silica aerogel is an especially good conductive insulator because silica is a poor conductor of heat—a metallic aerogel, on the other hand, would be a less effective insulator. Carbon aerogel is a good radiative insulator because carbon absorbs the infrared radiation that transfers heat at standard temperatures. The most insulative aerogel is silica aerogel with carbon added to it.
Due to its hygroscopic nature, aerogel feels dry and acts as a strong desiccant. Persons handling aerogel for extended periods of time should wear gloves to prevent the appearance of dry brittle spots on their hands.
Since it is 99.8% air, it appears semi-transparent. The color it does have is due to Rayleigh scattering of the shorter wavelengths of visible light by the nanosized dendritic structure. This causes it to appear smoky blue against dark backgrounds and yellowish against bright backgrounds.
Aerogels by themselves are hydrophilic, but chemical treatment can make them hydrophobic. If they absorb moisture they usually suffer a structural change, such as contraction, and deteriorate, but degradation can be prevented by making them hydrophobic. Aerogels with hydrophobic interiors are less susceptible to degradation than aerogels with only an outer hydrophobic layer, even if a crack penetrates the surface. Hydrophobic treatment facilitates processing because it allows the use of a water jet cutter.
Types
Silica aerogels
Aerogel produced at Florida State University by Elliot Schwartz and Robert PalmerSilica aerogel is the most common type of aerogel and the most extensively studied and used. It is a silica-based substance, derived from silica gel. The world's lowest-density solid is a silica nanofoam at 1 mg/cm3, which is the evacuated version of the record-aerogel of 1.9 mg/cm3. The density of air is 1.2 mg/cm3.
Silica aerogel strongly absorbs infrared radiation. It allows the construction of materials that let light into buildings but trap heat for solar heating.
It has remarkable thermal insulative properties, having an extremely low thermal conductivity: from 0.03 W/m·K down to 0.004 W/m·K,[5] which correspond to R-values of 14 to 105 for 3.5 inch thickness. For comparison, typical wall insulation is 13 for 3.5 inch thickness. Its melting point is 1,473 K (1,200 °C or 2,192 °F).
Silica aerogel holds 15 entries[citation needed] in Guinness World Records for material properties, including best insulator and lowest-density solid.
Carbon aerogels
Carbon aerogels are composed of particles with sizes in the nanometer range, covalently bonded together. They have very high porosity (over 50%, with pore diameter under 100 nm) and surface areas ranging between 400–1000 m²/g. They are often manufactured as composite paper: non-woven paper made of carbon fibers, impregnated with resorcinol-formaldehyde aerogel, and pyrolyzed. Depending on the density, carbon aerogels may be electrically conductive, making composite aerogel paper useful for electrodes in capacitors or deionization electrodes. Due to their extremely high surface area, carbon aerogels are used to create supercapacitors, with values ranging up to thousands of farads based on a capacitance of 104 F/g and 77 F/cm³. Carbon aerogels are also extremely "black" in the infrared spectrum, reflecting only 0.3% of radiation between 250 nm and 14.3 µm, making them efficient for solar energy collectors.
The term "aerogel" has been incorrectly used to describe airy masses of carbon nanotubes produced through certain chemical vapor deposition techniques—such materials can be spun into fibers with strength greater than Kevlar, and unique electrical properties. These materials are not aerogels, however, since they do not have a monolithic internal structure and do not have the regular pore structure characteristic of aerogels.
Alumina aerogels
Aerogels made with aluminium oxide are known as alumina aerogels. These aerogels are used as catalysts, especially when "metal-doped" with another metal. Nickel-alumina aerogel is the most common combination. Alumina aerogels are also examined by NASA for capturing of hypervelocity particles; a formulation doped with gadolinium and terbium could fluoresce at the particle impact site, with amount of fluorescence dependent on impact velocity.
Other aerogels
SEAgel is a material similar to organic aerogel, made of agar.
Chalcogels are a type of aerogel made of chalcogens (the column of elements on the periodic table beginning with oxygen) such as sulfur, selenium, and other elements. Research is ongoing, and metals less expensive than platinum have also been used in its creation.
Aerogels made of Cadmium selenide quantum dots in a porous 3-D network have recently been developed for use in the semiconductor industry.
Uses
The Stardust dust collector with aerogel blocks. (NASA)There are a variety of tasks for which aerogels are used.
■Commercially, aerogels have been used in granular form to add insulation to skylights.
■Transparent silica aerogel would be very suitable as a thermal insulation material for windows, significantly limiting thermal losses of buildings. One research team (http://zerogaerogel.com) has shown that producing aerogel in a weightless environment can produce particles with a more uniform size and reduce the Rayleigh scattering effect in silica aerogel, thus making the aerogel less blue and more transparent.
■Its high surface area leads to many applications, such as a chemical absorber for cleaning up spills (see adsorption). This feature also gives it great potential as a catalyst or a catalyst carrier.
■Aerogel particles are also used as thickening agents in some paints and cosmetics.
■Aerogels are being tested for use in targets for the National Ignition Facility.
■Aerogel performance may be augmented for a specific application by the addition of dopants, reinforcing structures, and hybridizing compounds. Using this approach, the breadth of applications for the material class may be greatly increased.
■Commercial manufacture of aerogel 'blankets' began around the year 2000. An aerogel blanket is a composite of silica aerogel and fibrous reinforcement that turns the brittle aerogel into a durable, flexible material. The mechanical and thermal properties of the product may be varied based upon the choice of reinforcing fibers, the aerogel matrix, and opacification additives included in the composite.
■NASA used aerogel to trap space dust particles aboard the Stardust spacecraft. The particles vaporize on impact with solids and pass through gases, but can be trapped in aerogels. NASA also used aerogel for thermal insulation of the Mars Rover and space suits.
■The US Navy is evaluating aerogel undergarments as passive thermal protection for divers.
■Aerogels are also used in particle physics as radiators in Cherenkov effect detectors. ACC system of the Belle detector, used in the Belle Experiment at KEKB, is a recent example of such use. The suitability of aerogels is determined by their low index of refraction, filling the gap between gases and liquids, and their transparency and solid state, making them easier to use than cryogenic liquids or compressed gases. Their low mass is also advantageous for space missions.
■Resorcinol-formaldehyde aerogels (polymers chemically similar to phenol formaldehyde resins) are mostly used as precursors for manufacture of carbon aerogels, or when an organic insulator with large surface is desired. They come as high-density material, with surface area about 600 m²/g.
■The first residential use of aerogel as an insulator is in the Georgia Institute of Technology's Solar Decathlon House where it is used as an insulator in the semi-transparent roof.
■Metal-aerogel nanocomposites can be prepared by impregnating the hydrogel with solution containing ions of the suitable noble or transition metals. The impregnated hydrogel is then irradiated with gamma rays, leading to precipitation of nanoparticles of the metal. Such composites can be used as catalysts, sensors, electromagnetic shielding, and in waste disposal. A prospective use of platinum-on-carbon catalysts is in fuel cells.
■Aerogel can be used as a drug delivery system due to its biocompatibility. Due to its high surface area and porous structure, drugs can be adsorbed from supercritical CO2. The release rate of the drugs can be tailored based on the properties of aerogel.
■Carbon aerogels are used in the construction of small electrochemical double layer supercapacitors. Due to the high surface area of the aerogel, these capacitors can be 1/2000th to 1/5000th the size of similarly rated electrolytic capacitors.Aerogel supercapacitors can have a very low impedance compared to normal supercapacitors and can absorb or produce very high peak currents. At present, such capacitors are polarity-sensitive and need to be wired in series if a working voltage of greater than about 2.75V is needed.
■Dunlop has recently incorporated aerogel into the mold of its new series of tennis racquets, and has previously used it in squash racquets.
■Chalcogels have shown promise in absorbing the heavy metal pollutants mercury, lead and cadmium from water.
■Aerogel is used to introduce disorder into superfluid Helium-3.
Production
Silica aerogel is made by drying a hydrogel composed of colloidal silica in an extreme environment. Specifically, the process starts with a liquid alcohol like ethanol which is mixed with a silicon alkoxide precursor to form a silicon dioxide sol gel (silica gel). Then, through a process called supercritical drying, the alcohol is removed from the gel. This is typically done by exchanging the ethanol for liquid acetone, allowing a better miscibility gradient, and then onto liquid carbon dioxide and then bringing the carbon dioxide above its critical point. A variant on this process involves the direct injection of supercritical carbon dioxide into the pressure vessel containing the aerogel. The end result removes all liquid from the gel and replaces it with gas, without allowing the gel structure to collapse or lose volume.
Aerogel composites have been made using a variety of continuous and discontinuous reinforcements. The high aspect ratio of fibers such as fiberglass have been used to reinforce aerogel composites with significantly improved mechanical properties.
Resorcinol-formaldehyde aerogel (RF aerogel) is made in a way similar to production of silica aerogel.
Carbon aerogel is made from a resorcinol-formaldehyde aerogel by its pyrolysis in inert gas atmosphere, leaving a matrix of carbon. It is commercially available as solid shapes, powders, or composite paper.
Safety
Silica-based aerogels are not known to be carcinogenic or toxic. However, they are a mechanical irritant to the eyes, skin, respiratory tract and digestive system. They also can induce dryness of the skin, eyes and mucous membranes. Therefore, it is recommended that protective gear including gloves and eye goggles be worn whenever handling aerogels.[20]
However, safety depends on the material from which the aerogel is made – it will be carcinogenic or toxic if the solid component has such characteristics.
Monday, May 18, 2009
THE PAIN OF REJECTION
Have you ever loved a girl? If the answer to the question is positive you have surely hit a jackpot.
As a matter of fact, each and every guy that I have known to exist has been smitten by a girl at some point of time in his life but out of this lot only a meager amount has confessed to their lady love. Can u guess why? What stops a man from baring his heart in front of the woman he loves? It’s nothing but ‘THE PAIN OF REJECTION’. What if she says no? What if she rejects me out rightly? These kinds of questions brew up in a lover’s mind.
Men simply can’t take the humiliation of being discarded by a girl. Instead of pondering over the process men fear the result. Don’t bother about the reply just say what your heart says. If the answer is yes, then awesome and if it’s a no then I must tell you that you are very lucky because what makes a difference is how you carry ‘THE PAIN OF REJECTION’.
Usually people get bogged down and depressed after being rejected, they loose the reason and motive to live. They find new imperfections in themselves and feel inferior to others.
But if you want your girl you’ll have to rise above the pain of being rejected and roll up your sleeves to get her.
You’ll have to ask yourself the question that ‘What was lacking in me so that she had to overlook me’? Then through an introspecting session and your conscience come up with the flaws in you and try to improve upon them. Then with a new polished and improved version of yourself hit back again to woo the woman of your life but beware u may get more negative replies ( as no one has a control over the matters of heart but god ). But you don’t give up and try until she is impelled to like you. You’ll find that in doing so you have excelled and achieved a great deal in life.
If you don’t believe me I have a petite and true story for you……..
A man named Rajiv Bhatia loved a girl from the deep depths of his heart. He proposed to the girl and she rejected him for a guy named Akshay Kumar. Rajiv was heart broken. But then he decided to do something substantial in his life and show her what she had lost. Now we know this Rajiv as the actor ‘AKSHAY KUMAR’.
So guys don’t sit back dreaming and fantasizing about the girl you love, sweep her by the feet looking into her gleaming eyes & enchant those magical words into her lovely ears hoping to be accepted and if you are not then you have a very good chance of becoming the next ‘AKSHAY KUMAR’ of India.
BY
NIPUN GUPTA
(Straight from the heart)
B-TECH (1st year)
PULP AND PAPER ENG.
IIT ROORKEE
As a matter of fact, each and every guy that I have known to exist has been smitten by a girl at some point of time in his life but out of this lot only a meager amount has confessed to their lady love. Can u guess why? What stops a man from baring his heart in front of the woman he loves? It’s nothing but ‘THE PAIN OF REJECTION’. What if she says no? What if she rejects me out rightly? These kinds of questions brew up in a lover’s mind.
Men simply can’t take the humiliation of being discarded by a girl. Instead of pondering over the process men fear the result. Don’t bother about the reply just say what your heart says. If the answer is yes, then awesome and if it’s a no then I must tell you that you are very lucky because what makes a difference is how you carry ‘THE PAIN OF REJECTION’.
Usually people get bogged down and depressed after being rejected, they loose the reason and motive to live. They find new imperfections in themselves and feel inferior to others.
But if you want your girl you’ll have to rise above the pain of being rejected and roll up your sleeves to get her.
You’ll have to ask yourself the question that ‘What was lacking in me so that she had to overlook me’? Then through an introspecting session and your conscience come up with the flaws in you and try to improve upon them. Then with a new polished and improved version of yourself hit back again to woo the woman of your life but beware u may get more negative replies ( as no one has a control over the matters of heart but god ). But you don’t give up and try until she is impelled to like you. You’ll find that in doing so you have excelled and achieved a great deal in life.
If you don’t believe me I have a petite and true story for you……..
A man named Rajiv Bhatia loved a girl from the deep depths of his heart. He proposed to the girl and she rejected him for a guy named Akshay Kumar. Rajiv was heart broken. But then he decided to do something substantial in his life and show her what she had lost. Now we know this Rajiv as the actor ‘AKSHAY KUMAR’.
So guys don’t sit back dreaming and fantasizing about the girl you love, sweep her by the feet looking into her gleaming eyes & enchant those magical words into her lovely ears hoping to be accepted and if you are not then you have a very good chance of becoming the next ‘AKSHAY KUMAR’ of India.
BY
NIPUN GUPTA
(Straight from the heart)
B-TECH (1st year)
PULP AND PAPER ENG.
IIT ROORKEE
Sunday, May 10, 2009
Mother- a Special Gift of God!
Nothing is impossible in this world if one person is with u,nothing can be taken from u if that person is with u,no one can cause u any damage, if that person is with u, even if u r sleeping , then also one person is there who is luking after u, u may be anywhere in this whole world, one person always wishes u to be successful, u may not be with that person, but her wishes, her help, her care ,her support will always be with u, u may forget her, but she can't even think of this , whenever u become sad, there is always one person who becomes more sad than u r and that person is your MOTHER.
Mother , this is a wonderful word in every person's life. Each person is closely attached to his/her mother and why not , after all this attachment is like an eternal relation.It's the greatest gift of God a person can ever have.Mother , mummy, mom, ma, etc are the most wonderful syllables a person have,these words r attached to the bottom of their hearts.
The relation between son and the mother is actually the attachment of their souls.They r so attached that a slightest of the troubles to one person produces great distress to the other.
Right from the childhood, when the child is not able to walk, speak, then it is the mother who luks after the child.She is so much concerned that at nights when the child starts crying she wakes up and then does not sleep until the child sleeps peacefully. She is always concerned abt the child, and always wants her child to be happy evertime and for giving that happiness to that child, she is able to do that which a person can't even think of doing.She does'nt ask for anything from God but the happiness of her child,this shows how greatly concerned she is.It is something which a person even if he wants can't do. This is an extraordinary gift and we must be thankful to God for providing such a divine relationship .
Ma, a monosyllabic word has more than just a sound.It is one of those wonderful words that makes the life on this world a great great one to live for.The mother always wants to hear those words and it gives her that utmost happiness which even the biggest of the gifts can't provide.
Being a full-time mother is one of the highest salaried jobs, since the payment is pure love and this payment is the most difficult to get.Tears start coming out when a person tries to think wat his mother has done for him all these years.It is an incredible work she has done, she has gone through those sleepless nights just to give you that peaceful sleep, she has missed her past just to secure your future, just to make u stand where u r, she has lost her enjoyable days just to ensure u r gearing up in the rite direction, she has been so helping and caring just to ensure that u get all the happiness in this world, when u become sad, she is the one who supports u, when u do some wrong thing, she is the one who teaches u , when u get wat u wanted , she is the most happiest person in the world, when u are saddened, she too gets saddened, when u want something, it is she who provides u, when u are going through the difficult times , it is she who provides u the much needed encouragement and makes u believe that u will overcome this thing and that too very soon.
She is ur support which does'nt decrease with time, she is ur helping shoulder , which is always there, she is ur best friend who enjoys ur success, she is the dearest relation one can ever get, and she is the most precious gift of God to a person and above all
SHE IS YOUR MOTHER!
Happy Mother's day Mumma!!
Mother , this is a wonderful word in every person's life. Each person is closely attached to his/her mother and why not , after all this attachment is like an eternal relation.It's the greatest gift of God a person can ever have.Mother , mummy, mom, ma, etc are the most wonderful syllables a person have,these words r attached to the bottom of their hearts.
The relation between son and the mother is actually the attachment of their souls.They r so attached that a slightest of the troubles to one person produces great distress to the other.
Right from the childhood, when the child is not able to walk, speak, then it is the mother who luks after the child.She is so much concerned that at nights when the child starts crying she wakes up and then does not sleep until the child sleeps peacefully. She is always concerned abt the child, and always wants her child to be happy evertime and for giving that happiness to that child, she is able to do that which a person can't even think of doing.She does'nt ask for anything from God but the happiness of her child,this shows how greatly concerned she is.It is something which a person even if he wants can't do. This is an extraordinary gift and we must be thankful to God for providing such a divine relationship .
Ma, a monosyllabic word has more than just a sound.It is one of those wonderful words that makes the life on this world a great great one to live for.The mother always wants to hear those words and it gives her that utmost happiness which even the biggest of the gifts can't provide.
Being a full-time mother is one of the highest salaried jobs, since the payment is pure love and this payment is the most difficult to get.Tears start coming out when a person tries to think wat his mother has done for him all these years.It is an incredible work she has done, she has gone through those sleepless nights just to give you that peaceful sleep, she has missed her past just to secure your future, just to make u stand where u r, she has lost her enjoyable days just to ensure u r gearing up in the rite direction, she has been so helping and caring just to ensure that u get all the happiness in this world, when u become sad, she is the one who supports u, when u do some wrong thing, she is the one who teaches u , when u get wat u wanted , she is the most happiest person in the world, when u are saddened, she too gets saddened, when u want something, it is she who provides u, when u are going through the difficult times , it is she who provides u the much needed encouragement and makes u believe that u will overcome this thing and that too very soon.
She is ur support which does'nt decrease with time, she is ur helping shoulder , which is always there, she is ur best friend who enjoys ur success, she is the dearest relation one can ever get, and she is the most precious gift of God to a person and above all
SHE IS YOUR MOTHER!
Happy Mother's day Mumma!!
Monday, May 4, 2009
मजाक बन गया मैं .
आज मैं आपको अपने बारे में कुछ बता रहा हूँ,
ध्यान एकत्रित करने के लिए कुछ समय मांग रहा हूँ,
माफ़ कीजियेगा अगर मज़ा न आए ,
परन्तु उदासी को भी मज़े के साथ बता रहा हूँ।
बात थी एक ज़माने की ,
थे हम अकल के कच्चे,
मजाक बनाया हमने ज़िन्दगी का,
क्या करें थे नन्हे बच्चे।
आया एक बार शेर मेरे सामने ,
राम राम कह पत्थर उठाकर लगा मैं कांपने,
बलवानों की तरह फेका पत्थर उसकी पीठ पर,
मजाक बन गया मैं जब पता चला की लगा पत्थर कुत्ते की रीढ़ पर।
एक बार लग गया मैं नदी में नहाने में,
नहाते नहाते आ गया जोश गाना गाने में,
आया बहार नदी के पानी में नहाकर,
फ़िर मजाक बन गया मैं जब पता चला आया बहार नाले में छलांग लगाकर।
और अजीब और गरीब किस्से आपको मैं बताता हूँ,
तो सुनिए और मज़ेदार किस्से अब मैं फरमाता हूँ।
था एक ज़माना मैं घुढ़सवारी कर रहा था,
घोडे पे सवारी करना मज़ा बन गया था,
घोडे वाले की बात सुन कर मैं अचम्भे में पड़ गया था,
क्योंकि गधा सवारी करके मैं गधा बन गया था।
उपर लिखे किस्सों से मैं मजाक बन गया था ,
पता नहीं क्यों मेरी नज़रों से मुझे धोखा मिल गया था ?
पता नहीं क्यों हँसी का पात्र बन गया था ?
फ़िर मजाक बन गया मैं जब याद आया की मैं अपना चश्मा लगना भूल गया था।
ध्यान एकत्रित करने के लिए कुछ समय मांग रहा हूँ,
माफ़ कीजियेगा अगर मज़ा न आए ,
परन्तु उदासी को भी मज़े के साथ बता रहा हूँ।
बात थी एक ज़माने की ,
थे हम अकल के कच्चे,
मजाक बनाया हमने ज़िन्दगी का,
क्या करें थे नन्हे बच्चे।
आया एक बार शेर मेरे सामने ,
राम राम कह पत्थर उठाकर लगा मैं कांपने,
बलवानों की तरह फेका पत्थर उसकी पीठ पर,
मजाक बन गया मैं जब पता चला की लगा पत्थर कुत्ते की रीढ़ पर।
एक बार लग गया मैं नदी में नहाने में,
नहाते नहाते आ गया जोश गाना गाने में,
आया बहार नदी के पानी में नहाकर,
फ़िर मजाक बन गया मैं जब पता चला आया बहार नाले में छलांग लगाकर।
और अजीब और गरीब किस्से आपको मैं बताता हूँ,
तो सुनिए और मज़ेदार किस्से अब मैं फरमाता हूँ।
था एक ज़माना मैं घुढ़सवारी कर रहा था,
घोडे पे सवारी करना मज़ा बन गया था,
घोडे वाले की बात सुन कर मैं अचम्भे में पड़ गया था,
क्योंकि गधा सवारी करके मैं गधा बन गया था।
उपर लिखे किस्सों से मैं मजाक बन गया था ,
पता नहीं क्यों मेरी नज़रों से मुझे धोखा मिल गया था ?
पता नहीं क्यों हँसी का पात्र बन गया था ?
फ़िर मजाक बन गया मैं जब याद आया की मैं अपना चश्मा लगना भूल गया था।
Sunday, May 3, 2009
Friday, May 1, 2009
Life- it's all about our thinking!!
This article is based on my experience .After living for this much of time , what I have got to know about life is what I am trying to explain in this post.
Life- what it is?? When people say that my life is good, my life is great etc. etc., I tend to think sometimes what makes the life great, what makes the life so interesting? I asked this question to many people and the ans was great. And then when I asked how ? they told just "aisehe". Infact people have developed this habit of saying that I am really enjoying, well It's great to enjoy but what makes your life this enjoyable is what my query is. What's the reason for you enjoyment?,and how far will you be enjoying?? How do you define fun? How does one define enjoyment??
To proceed, I would say that there is nothing called excitement, nor enjoyment nor boring not sadness. These are all the terms invented by some of the minds who just changed the meaning of life and then tried to associate these words with the lives.If a person pretends that he is happy, one assuumes vow man, what life is he having! Vow what life Amitabh Bachan has!
Kash meri bhi life aise hoti, etc. etc. Well, guys if anyone of you thinks like that then certainly you need to read this article.
According to me , life is nothing but the outcome of what one does.As you sow so shall you reap- a famous quote. Well, this defines what will be the outcome but still one question remains, what makes the life interesting?It may be the case that the reason for enjoyment for one person may not be for another one.Like for example, if one is getting the food everday he thinks that he is happy, but if you go to the rich people, they don't beleive happiness lies in having food everday but what they beleive in is having good food ,no tension etc.etc. for their happiness.So in short, Life's happiness is defined separately by one's choice.A person can redefine the word happiness and can have the most wanted happiness.If one redifines the meaning of these words peace, happiness, enjoyment etc then certainly he is there to enjoy (not only in his own definitions but also in other's as well.)
So friends, Life is great if you are satisfied with what you have or what you are getting day by day.
But this does not mean that you should not aim too high and must be satisfied with where you are :P. enjoy!!
GO ON AND ENJOY BUT ALWAYS AIM HIGH AND DON'T BE SADDENED WITH WHAT YOU DON'T HAVE.
Life- what it is?? When people say that my life is good, my life is great etc. etc., I tend to think sometimes what makes the life great, what makes the life so interesting? I asked this question to many people and the ans was great. And then when I asked how ? they told just "aisehe". Infact people have developed this habit of saying that I am really enjoying, well It's great to enjoy but what makes your life this enjoyable is what my query is. What's the reason for you enjoyment?,and how far will you be enjoying?? How do you define fun? How does one define enjoyment??
To proceed, I would say that there is nothing called excitement, nor enjoyment nor boring not sadness. These are all the terms invented by some of the minds who just changed the meaning of life and then tried to associate these words with the lives.If a person pretends that he is happy, one assuumes vow man, what life is he having! Vow what life Amitabh Bachan has!
Kash meri bhi life aise hoti, etc. etc. Well, guys if anyone of you thinks like that then certainly you need to read this article.
According to me , life is nothing but the outcome of what one does.As you sow so shall you reap- a famous quote. Well, this defines what will be the outcome but still one question remains, what makes the life interesting?It may be the case that the reason for enjoyment for one person may not be for another one.Like for example, if one is getting the food everday he thinks that he is happy, but if you go to the rich people, they don't beleive happiness lies in having food everday but what they beleive in is having good food ,no tension etc.etc. for their happiness.So in short, Life's happiness is defined separately by one's choice.A person can redefine the word happiness and can have the most wanted happiness.If one redifines the meaning of these words peace, happiness, enjoyment etc then certainly he is there to enjoy (not only in his own definitions but also in other's as well.)
So friends, Life is great if you are satisfied with what you have or what you are getting day by day.
But this does not mean that you should not aim too high and must be satisfied with where you are :P. enjoy!!
GO ON AND ENJOY BUT ALWAYS AIM HIGH AND DON'T BE SADDENED WITH WHAT YOU DON'T HAVE.
Wednesday, January 21, 2009
wake up..
सपने में कोई अपना
सोच में डूबा हुआ मैंने सोचा एक सपना,
था उसमे एक अजीब इंसान कोई अपना,
उसका चेहरा देखने ke लिए मैंने अनेक सहारे लिए,
मेरे ह्रदय ने मुझसे उस वक्त लाखों प्रशन किए .
पुछा मैंने उससे उसका नाम था,
जानना चाह मैंने उसका काम था,
उत्तर देने से पहले चला गया वोह,
खो गया जैसे की कोई आसमान था।
फ़िर आया वोह उसी तरह अगली रात,
की उससे उसदिन मैंने मुलाक़ात,
उत्तर दिया और बहुत समझाया उसने मुझको,
दे गया वोह मेरे दिल को मात .
samajhaya उसने भविष्य के बारे में,
आदेश दिया छोड़ने को भविष्य उसके सहारे में,
बताया उसने की वोह मेरा भविष्य था,
बनाया मुझे उसने अपना शिष्य था।
आँखें खोल दी उसने जाते ही साथ,
चैन मिला उसके शब्दों से उस रात,
अच्छे और बुरे की पहचान आ गई मुझमें,
हो नहीं पाई फिरसे usase मुलाक़ात।
उसने मेरे कर्मों का वर्णन किया था,
मैंने कौनसे कौनसे ग़लत कामों को किया था,
उसने अपनी शिक्षा से शिक्षक का नाम लिया था,
उसने मुझे अच्छा इंसान बना दिया था .
सोच में डूबा हुआ मैंने सोचा एक सपना,
था उसमे एक अजीब इंसान कोई अपना,
उसका चेहरा देखने ke लिए मैंने अनेक सहारे लिए,
मेरे ह्रदय ने मुझसे उस वक्त लाखों प्रशन किए .
पुछा मैंने उससे उसका नाम था,
जानना चाह मैंने उसका काम था,
उत्तर देने से पहले चला गया वोह,
खो गया जैसे की कोई आसमान था।
फ़िर आया वोह उसी तरह अगली रात,
की उससे उसदिन मैंने मुलाक़ात,
उत्तर दिया और बहुत समझाया उसने मुझको,
दे गया वोह मेरे दिल को मात .
samajhaya उसने भविष्य के बारे में,
आदेश दिया छोड़ने को भविष्य उसके सहारे में,
बताया उसने की वोह मेरा भविष्य था,
बनाया मुझे उसने अपना शिष्य था।
आँखें खोल दी उसने जाते ही साथ,
चैन मिला उसके शब्दों से उस रात,
अच्छे और बुरे की पहचान आ गई मुझमें,
हो नहीं पाई फिरसे usase मुलाक़ात।
उसने मेरे कर्मों का वर्णन किया था,
मैंने कौनसे कौनसे ग़लत कामों को किया था,
उसने अपनी शिक्षा से शिक्षक का नाम लिया था,
उसने मुझे अच्छा इंसान बना दिया था .
Sunday, January 18, 2009
Life and death
जीवन और मृत्यु
एक जानवर की देखी मैंने तस्वीर थी,
मेरे हाथों में उसकी तकदीर थी,
एक तीर चला दिया मैंने,
टूटी हुई जीवन रेखा उसके हाथों की लकीर थी.
मर गया वोह मेरे क़दमों में ,
खो गया वोह मेरी यादों में,
सामने निकला वोह एक रात,
हो गया मुझसे उसदिन अपराध।
बदकिस्मती में आती हैं मुश्किलें सभी,
मरना था उसे कभी न कभी,
अपनानी पड़ेगी मुझे यह कड़वी सच्चाई,
नहीं हो पायेगी मेरे दिल की भरपाई।
मानना पड़ेगा यही सच है,
मारा है जो वह एक गज है,
छोड़ दिया चलाना तीर मैंने आज से,
अमर हो गया वोह पेच्ली रात से।
अपराध करके पा लिया मैंने अंजाम,
शायद यही है जीवन मृत्यु का नाम.
एक जानवर की देखी मैंने तस्वीर थी,
मेरे हाथों में उसकी तकदीर थी,
एक तीर चला दिया मैंने,
टूटी हुई जीवन रेखा उसके हाथों की लकीर थी.
मर गया वोह मेरे क़दमों में ,
खो गया वोह मेरी यादों में,
सामने निकला वोह एक रात,
हो गया मुझसे उसदिन अपराध।
बदकिस्मती में आती हैं मुश्किलें सभी,
मरना था उसे कभी न कभी,
अपनानी पड़ेगी मुझे यह कड़वी सच्चाई,
नहीं हो पायेगी मेरे दिल की भरपाई।
मानना पड़ेगा यही सच है,
मारा है जो वह एक गज है,
छोड़ दिया चलाना तीर मैंने आज से,
अमर हो गया वोह पेच्ली रात से।
अपराध करके पा लिया मैंने अंजाम,
शायद यही है जीवन मृत्यु का नाम.
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