Jakhong Village

Jakhong Village

Jakhong is a small village in West Khasi Hills District of Meghalaya State, India. It belongs to Mairang Constituency with 130 houses and around 700 people living in it. Jakhong is a village bordered with river Khri in the east and north, river Umlah in the south and river Rahkep in the west. Mawkarah, Umpongdeng, Khlawmariaw, Umriah, Umiin, Warmawsaw and Jingkieng ingding are some of its neighboring villages. Jakong village is surrounded with thick jungles and splendid waterfalls. Till now Jakhong provides and opportunity for tourist to see the natural habitat of animals like elephants, tigers, deer, bear, hyenas, jackals, monkeys and others.

Jakhong is richly blessed with many medicinal plants, animals, birds and fish. The soil is very fertile and so the people could cultivate paddy of different kinds, potatoes, maize, sesame, pumpkins, mustard leaves and different types of vegetables and fruits. Jakhong is also well known for the supply of soft-brooms, timber, pineapple, pumpkins, local rice and others.

Bynniaw ki nong Jakhong namar ka Surok

“Hangno kong phi kha ia ine I khun”, la kylli I doctor ia I longkmie na Jakhong ba wan shim dawai, bad ita I longkmie I la jubab, “nga kha ha lynti iew por ba mut leit kha ha hospital doctor”. Katno sngewshongpap bad sngewsangsot ba haduh mynta dang don kum kine ki jingjia ha ka Ri Tipbriew tipblei jongngi. Tangba kane kam dei tang ka apot jong kane kawei ka longkmie. Wan sha kine ki thain Jakhong, Khlawmariaw, Umpongdeng, Nongrilong bad kiwei de kin sa iathuh iaphi ba kumno ki la shem jynjar bad lanot dei naka daw ba ym don surok. Ki briew ki la shu kha bad iap ha ki lynti iew ne ki iing ki sem dei tang nakadaw ba kim lah ban poi hospital bad ym don dispensary ha jan. Lada don dispensary kum ha Jakhong ym don pat sa ki nongtrei. Balei mo ka sorkar bad ki nongmihkhmat ki dang matlah ia ki jingeh jong ki paidbah? Bunsien ka sorkar wat lada ka buh ia ka thong kaba ha khmat ban pynioh ia ki surok, hynrei ka la shu kut tang ha kaba buh ia ka thong khem da pyntreikam pat.

Ka shnong Jakhong, ba hap ha Mairang constituency bad ba long kum ka centre ia kiwei pat ki shnong ha kine ki thain, ka la ioh ia ka surok kyndew PWD naduh u snem 1997. Leit sha kane ka shnong bad phin sa iohi ka la long kumno kane ka surok mynta. Kane ka surok ka la long kum ki jaka dem ki shynreh bad ki don ki jaka ba wat ki briew kim nud shuh ban iaid namar ba ka lah kylla thliew. Ki Rangbah Shnong kine ki thain ki la leit sha ka sorkar hynrei ka sorkar ka pynshah da ka shkor kynriang bad ka pynshad shrieh pynban iaki katba ki leit. Katkum I paieid Krispin, “ka sorkar ka patiaw ia ngi tang ha ka por election bad hadien katta patde ki pynlong nongwei iangi”. Ka shnong Jakhong ka long ka shnong ba seisoh bha ha ka rep ka riang hynrei dei ba ym don surok ban pynpoi ha iew, ki jingthung jingtep ki shu sah pyut ha iing bad ha klaw. Te kumno kein ki briew kin lah ban kyntiew ia ka roi ka par bad ia ka ioh ka kot, haba kim don ia ka surok ka babit babiang? Lada ka sorkar ka sngew ba ka don ia ka thong ban kyntiew ia ka ioh ka kot bad ka roi ka par kam donkam ban ai ia kiwei ki kam pynroi, hynrei kaba hakhmat eh ai shuwa ia ka surok kaba bit babiang bad ia kiwei ki kam pynroi sa ia peit pat hadien.

Ka shnong Jakhong ka long tang kawei na ki shnong ba bun ba la shah lehbein ha ka sorkar Meghalaya. Balei mo ka sorkar Meghalaya ka klet ia ki nongkyndong kiba donkam ban ioh ia ka hok? Shaei lut ka pisa ba ai ka sorkar kmie lyngba ka Rural Development scheme? Nga tharai ki briew ba sah sha nongkyndong ruh ki don hok ban ioh ia ka bha ka bynta ba la mang ka sorkar kmie na Delhi. Ngi kum ki khun samla ngi kyrpad ia ka sorkar bad ki NGO ba kin ym tep eitmiaw ia ki nongkyndong namar ki dei ki mynta ba kongsan jong ka jylla Meghalaya. Ka Sorkar ka dei ban pynbiang ia ki jingdonkam ba kongsan kum ka surok, ka lait bad ka um sha ki nongkyndong namar ia ka bam ki lah ioh hi na ka rep ka riang.

Ka Jingkyrpad kam ju sepei ia ki briew ha ki thain Jakhong

Ki nong Jakhong bad ki shnong ba don ha kine ki thain ki la sdang ban iohi ba ka Sorkar ka la sdang ban sngap ia ka sur myllung jongki. Ki nong Jakhong, Umpongdeng, Khlawmariaw, Uming, Umriah, Umsa khlawmariaw ki la sngewnguh ia ki nongpyniaid ka Mairang Constituency ba ki la shim khia ban pyntreikam da kaba shna bad siang surok rong (black topping) noh ia ka surok na Mawkarah sha Jakhong. Mynta ka shong ha ki briew kine ki thain ba kin iatrei lang bad ki contractor bad shna shisha ka surok kaba bha ym ka surok ba shu shna malu mala bad sa tep noh iaka pisa sha ka pla. Ngi don ka jingkyrmen ba kane ka jingthmu ka sorkar ban ai surok rong noh wat tang 10km kan sa iarap shibun ia ki briew kine ki thain ban kham ioh kamet ka bakoit ba khiah, ban kham roi ha ka ioh ka kot (economy) bad ban kham long ka jaka ba ki Tourist ki lah ban wan peit kai ia ki katto katne ki jaka ba ym pat ju poi mano mano. Ki briew kine ki thain ki dei ban iatrei lang bad ka Sorkar ban ioh ka surok babha ym ban shu trei tangdep ia ka surok. Ka jingtrei bha mynta kan sa pynduna ia ki jingjynjar hadien. “Ka jingiatrei lang ka wanrah ia ka roi ka par bad ka jingkmen ha ka jingim jongngi”.

Ka jingkhwai dohkha ba wanrah jingkmen ha Jakhong

“Lah ngat, lah ngat!!! Pyrta jam ki khynnah bad ki longkmie tang shu iohi ia ki dohkha ba kynjut ki nongkhwai ha ka jingpynialeh competition khwai dohkha ba nyngkong tam ha ka shnong Jakhong ha ka 8 tarik October. Ka Jingpynialeh competition khwai dohkha ha ka pung I kong Iobina Lyngdoh bad I bah Carelus Peinlang, ba la pyniaid da I Bah Charles Lyngdoh, Secretary shnong Jakhong bad I Kong Iobina Lyngdoh, ka la khring shibun ki nongkhwai na West Khasi Hills bad na Ri Bhoi Districts bad ka la pynbyrngia shikatdei ia ki khynnah, samla, longkmie longkpa ki ba khlem iashim bynta. La don palat ia ki 70 ngut ki nongkhwai ba la iashim bynta ban pyni ia ka sap khwai jongki bad ban pashad ia la ka bok ka rwiang ha ka pung ha Jakhong ban ioh ia ki dohkha ban ia muja bad ia ka prize pisa ban thep ha ka pla. I nong Umiien I la ioh ka dohkha ba 1.300kg bad I la ioh rah ia ka prize ba nyngkong. Kane ka competition ka la long kum ka Bal-mela ka ba wanrah jingkmen bad jingiakynduh lang jong ki briew na shnong na thaw bad ki briew na ki shnong ba marjan.

Ka shnong Jakhong ka hap hapoh ka Mairang Constituency, West Khasi Hills bad ka don hajan Warmawsaw, Ri Bhoi District. Te kane ka competition Khwai dohkha ka la khring ia ki ba bun ki briew na baroh ar district ki ba lah poi bad ki bym pat ju poi ha kane ka shnong. La don ruh ki nongkhwai ki bym shym la iohkwai shuh namar ba jah lynti ha khlaw. Ka shnong Jakhong bad ki shnong ha kine ki thain ki la sah dum namar ba ym don surok ba thikna. Ka Jakhong ka la ioh surok khyndew PWD naduh U snem 1997 bad haduh mynta ym pat don surok rong. Ka jingpynkhwai dohkha ha kane ka shnong ba la iashim bynta da bun bha ki nongkhwai, ki ba iaid da ka kjat ban poi sha kane ka shnong, ka pynpaw shai kdar ba ki nongkyndong ruh ki don ki jaka puta ba kongsan bha ha ka jylla Meghalaya ban khring ia ki tourist bad ban pynroi ia ka ioh ka kot ym tang jongki nongkyndong hynrei ia ka jylla baroh kawei. Ia katei ka pung la ioh jingiarap na ka ophis Fisheries bad ka la iarap shisha ia ki briew ym tang ka ioh ka kot hynrei ban ai jingkmen bad ban pyniatylli lang ia ki briew ha kine ki thain.

Pynsngewsarong ka NET exam ia ki Nongkyndong

Ka jingpass jong I Gilbert Armstrong Lyngdoh Marshillong, khun jong I kong Iobina Lyngdoh Marshillong, ia ka NET exam 2011, ka la pysngewsarong shisha ia ki nong Jakhong bad ki briew sha kine ki thain. I Gilbert I la long I wei na ki arngut ki khynnah NEHU Political Science Department ba la pass ia kane ka exam. Katkum ka jingtip jongngi I Gilbert I dei I ba Nyngkong tam ha ka thain Nongkhlaw barohkawei ba la pass ia ka NET exam. Ki briew kane ka thain ki la sngewsarong shisha ba la don I ba pass kum kane ka exam na ka shnong bym pat don surok thikna, bym pat don telephone connection, ka jaka bym pat don skul ba bha ne hospital. Ngi na ka shnong Jakhong ngi ai khublei kitbok kitrwiang ia I ne ki khun binong bishong ka shnong. I la long I briew ba trei shitom shisha bad I la wanrah nam ia ka ki briew ka thain Nongkhlaw baroh kawei. Ka jingpass jongi ka pyni ba wat ki nongkyndong ruh ki don ki sap ki phong ban kiew sha ka kyrdan jong ka nam bad ka burom. Ki rang ki thei nongkyndong kim dei ban sngew ba ki biej ki them bad sah ha jingdum hynrei ki dei ban don ka mynseim ialeh bad bud ia ki dienjat jong U Tirot Sing, U khla kawait ka Ri Khasi jongngi. Haba ngi don ka mon ka lad ka lynti ka plie iangi.

I Gilbert mynta I dang thoh ia ka exam II MA (Pol) ha NEHU. I la long ruh I ba la ioh ia ka award ICYM West Khasi Hills hadien ba I la pass ia ka class XII. I lah ioh Vth rank ruh ha ka degree jongi.

Nga phah shaphi ia ka ne ka khubor ym namar ba ngi kwah pynbna nam ba I Gilbert I la pass ia ka NET exam hynrei ban pyni nuksa ba wat ki Nongkyndong ruh ki ba long majority ha Meghalaya ki lah ban poi sha ka kyrdan jongka nam bad ka burom. Te lada long kaba lah sngewbha seh ai jaka lem wat tang kyndiat ruh ha ka kot khubor jongphi. U Blei un sa kyrkhu ia ka jingbha jongphi.

Ioh 4^th rank na Jakhong

Katno ngi ki nong Jakhong, Mairang ngi sngew sarong ba I Gilbert Armstrong Lyngdoh Marshillong, khun jong I kong Iobina Lyngdoh Marshillong, I la ioh 4^th rank ha ka II MA (Pol) final exam, NEHU 2011. Ngi na ka shnong Jakhong ngi ai khublei kitbok kitrwiang ia I ne I khun binong bishon ka shnong. I Gilbert I la pass ruh ia ka NET exam, 2011, I la ioh ia ka award ICYM West Khasi Hills hadien ba I la pass ia ka class XII na Tripura bad I lah ioh Vth rank ruh ha ka degree jongi. Ka jingpass jongi ka pyni ba wat ki nongkyndong ruh ki don ki sap ki phong ban kiew sha ka kyrdan jong ka nam bad ka burom. Ki rang ki thei nongkyndong kim dei ban sngew ba ki biej ki them bad sah ha jingdum hynrei ki dei ban don ka mynsiem ialeh bad bud ia ki dienjat jong U Tirot Sing, U khla kawait ka Ri Khasi jongngi. Haba ngi don ka mon ka lad ka lynti ka plie iangi. Congratulation Gilbert Armstrong bad nang iai kiew sha phrang.

Nanotubes are dream come true in Science and Technology

Nanotubes are dream come true in Science and Technology

Table of Contents

General Introduction

Definition of Nano Technology

Definition of Nanotubes

Types of Nanotubes

1. Zigzag nanotube (n, 0)

2. Armchair nanotube (n,n)

3. Chiral nanotube (n,m)

4. Membrane nanotubes, membrane nanotubules or cytonemes

5. Inorganic nanotube

6. DNA nanotube

7. Carbon nanotubes

7.1.Types of Carbon Nanotubes

7.1.1. Single-walled Carbon nanotubes

7.1.2. Multi-walled Carbon nanotubes

7.1.3. Nanotorus

7.1.4. Carbon nanobuds

7.1.5. Cup stacked carbon nanotubes

7.2.Properties of Carbon Nanotubes

Application of Nanotubes

Conclusion

Bibliography

Nanotubes are dream come true in Science and Technology

“Life is in flux”, said Heraclitus. Nothing in this universe is fixed. Human being and Cosmos keeps changing from time to time. Static life could be said as an enemy of human being because human being wants to move from good, better, best and beyond. In the process of evolving or changing science and technology also change from traditional to modern or from simplicity to complexity. Science and technology have changed from slow aircraft of Wright brothers to supersonic plane and people can perform experiment on tiniest particles which cannot be seen with our naked eyes. Science existed since the beginning of the universe and in fact the formation of the universe itself is part of science. Science and technology have a tremendous impact in human life and in Cosmos. Our body according to mechanical engineering is a complex machine. The different parts of our body, internal and external could be known and healed when we get sick due to the help of science and technology. Mentally, spiritually, physically, socially and even in our educational system we are affected by science and technology. Science and technology is a very broad concept because it includes every aspects of macro, medium and micro sciences and it includes space, time, mass, motion and simultaneity. It is wise to know different aspects of science and technology but it is also foolish to deal it in one single study. So here I will dwell only in one aspect of Science that is Nano-technology and within it I will talk more about Nano-tubes.

Ralph C. Merkle, Ph.D said, “Nanotechnology: It’s a Small, Small, Small, Small World”. Nano literally means 10 to the power -9. Nanotechnology is an innovative development in science and technology. It covers different walks of life like health, education, business, transports, and many more. Nanoscience is the world of atoms, molecules, macromolecules, quantum, dots, and macromolecular assemblies. Nanotechnology is the design, characterization, production and application of structures, devices and systems. The term “nanotechnology” was defined by Tokyo University professor Norio Taniguchi in 1974 as, “Nano-technology mainly consists of the processing, separation, consolidation, and deformation of materials by one atom of one molecule”. Nanotechnology includes many techniques used to create structures at a size scale below 100nm, including those used for fabrication of nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, further ion beam machining, nanoimprint lithography, and molecular vapor deposition, and copolymers.[1]

Nanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometers. One nanometer (nm) is one billionth, or 10−9, of a meter. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biomaterials and energy production.[2] Nano technology is a technology of rearranging and processing of atoms and molecules to fabricate materials to nano specifications such as a nanometre. Materials and devices designed and made at the molecular level would be quite different from those of daily use today. It is so profound that it will touch all aspects of economy and society. Through the developments in nano technology, energy will be clean and abundant, the environment will have been repaired to a pristine state, and any kind of material artefact can be made for almost no cost.[3] Current applications for nanotechnology are dominated by tools for scientists, and by new materials that are structured on the nanoscale. Such materials are used in cosmetics, health and medicine and in a variety of manufactured goods. The electronics and information technology industries are also a prominent driver for these new technologies. Carbon nanotubes have potential applications in electronics, improved materials, and drug delivery. Studying about nanotechnology would be incomplete without knowing about Nanotubes because they are vital parts of nanotechnology.

A Nanotube is a nanometer-scale tube-like structure. Nanotubes are being studied for use as photon ballistic waveguides as interconnects in quantum dot/quantum effect well photon logic arrays.[4] Nanotubes come in a variety of flavors: long, short, single-walled, multi-walled, open, closed, with different types of spiral structure, etc. Nanotubes are of great importance in the field of industries, education, health, research and construction. One of the recent developments ‘Smart’ bio nanotubes is used to improve the delivery of drugs and gene systems. The nanotubes are ‘smart’ because in the future they could be designed to encapsulate and then open up to deliver a drug or gene in a particular location in the body. Nanotubes are members of the fullerene structural family, that includes the spherical buckyballs and at the ends of a nanotube it may be capped with a hemisphere of the buckyball structure. Nanotubes are considered close cousins of buckminsterfullerene. Nanotubes are mostly found with closed ends on either side, though open tubes are seen. Thus these are three dimensional closed-cage objects, and may be considered as elongated fullerences.[5] Nanotubes can be either electrically conductive or semiconductive, depending on their helicity, leading to nanoscale wires and electrical components. A nanotube is a nanometer-scale tube-like structure and may refer to Carbon nanotube, Inorganic nanotube, DNA nanotube, Membrane nanotube, Zigzag nanotube, Armchair nanotube and Chiral nanotube.

Types of Nanotubes

Nanotubes are stiffer than steel, and are essentially rolled-up sheets of carbon hexagons. Electrically, nanotubes can be insulators, semiconductors, or conductors and are expected to exhibit magnetoresistance qualities .[6] For every effect there will be a cause and so depending on the rolling angle, the types of nanotubes that are possible: Armchair, Zigzag, Chiral, Membrane nanotubes, Inorganic nanotube, DNA nanotube and Carbon nanotubes. The names ‘armchair’ and ‘zigzag’ refer to the pattern of carbon bonds around the tube’s circumference. The nanotube's chirality, along with its diameter, determine its electrical properties. The armchair structure has metallic characteristics. Both zigzag and chiral structures produce band gaps, making these nanotubes semiconductors. Types of Nanotubes are;

1. Zigzag nanotube (n, 0)

A carbon nanotube formed from a graphite sheet that is rolled up so that it has a zigzag is known as Zigzag nanotube. A thirty degree roll (green to blue) produces an armchair pattern and a zero degree roll (green to red) makes a zigzag.

2. Armchair nanotube (n,n)

When a carbon nanotube is formed from a graphite sheet that is rolled up so that the edge is in the shape of armchairs is known as Armchair nanotube. Carbon nanotubes at the fundamental level are a single sheet of graphite (hybridization) that is rolled upon itself and connected at the edge. Armchair nanotubes correspond to the configuration with no ‘twist’ in the rolling. The armchair structure has metallic characteristics. The thinnest carbon nanotube is armchair (2,2) CNT with a diameter of 3 A.[7]

3. Chiral nanotube (n,m)

When a carbon nanotube is formed from a graphite sheet that is rolled up so that the succession of hexagons of carbon atoms on a particular cylinder makes an angle with the axis of the nanotube it is known as Chiral nanotube. Rolling the lattice at different angles creates a visible twist or spiral in the nanotube’s molecular structure, though the overall shape remains cylindrical.[8] The nanotube's chirality, along with its diameter, determines its electrical properties. Nanotubes can have different electronic properties depending on the chirality.

4. Membrane nanotubes, membrane nanotubules or cytonemes

Membrane nanotubes, membrane nanotubules or cytonemes are long and thin tubes formed from the plasma membrane that connects different animal cells over long distances. The structures of these nanotubes may be involved in cell-to-cell communication, transfer of nucleic acids between cells in a tissue, and the spread of pathogens or toxins such as HIV and prions. Membrane nanotubes were first described in a 1999 Cell article examining the development of Drosophila melanogaster wing imaginal discs.[9] A membrane structure also connects various types of immune cell together, connects between cells in tissue culture, interconnect plant cells and interconnect plastids.

5. Inorganic nanotube

An inorganic nanotube is a cylindrical molecule often composed of metal oxides, and morphologically similar to a carbon nanotube. Inorganic nanotubes have been observed to occur naturally in some mineral deposits.[10] Inorganic nanotubes have been made out of materials like Tungsten disulfide, Boron nitride, Silicon, Titanium dioxide, Molybdenum disulfide, Copper, and Bismuth. Inorganic nanotubes are heavier than carbon nanotubes and not as strong under tensile stress, but they are particularly strong under compression, leading to potential applications in impact-resistant applications such as bulletproof vests. [11] Recent findings revealed that inorganic nanotubes are constructed from main group elements, boron nitride (borazine).

6. DNA nanotube

DNA nanotube is a branch of nanotechnology which uses the molecular recognition properties of DNA and other nucleic acids to create designed, artificial structures out of DNA for technological purposes. In DNA nanotube DNA is used as a structural material rather than as a carrier of genetic information, making it an example of bio-nanotechnology. DNA nanotechnology has applications in molecular self-assembly and in DNA computing.[12]The design of DNA nanotubes can be Structural design and Sequence design. Structural design includes Tile-based structures which breaks the target structure into smaller units and is used for DNA computing. Folding structures is a design which makes the nanostructure out of a single long strand. Kinetic assembly is a design to control the kinetics of DNA. Sequence design is a design of assigning a specific nucleic acid base sequence to each strand so that they will associate into a desired conformation.

7. Carbon nanotubes

Silicon is the wonder material of the computer age and Carbon nanotubes are the wonder materials of electronics and computing. One of the most prominent building blocks of nanotechnology is Carbon nanotubes. Carbon nanotubes was discovered by SumioIijima of NEC in 1991. The extraordinary properties of Carbon nanotubes revealed the potential to revolutionize many technologies. Carbon nanotubes (CNTs) are allotropes of carbon which are effectively long, thin cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, significantly larger than any other material. These cylindrical carbon molecules have novel properties, making them potentially useful in many applications in nanotechnology, electronics, optics, and other fields of materials science, as well as potential uses in architectural fields. Carbon nanotubes are basically sheets of graphite rolled up into a tube and it can also be curl in a number of ways. Carbon nanotubes is one hundred times the tensile strength of steel, thermal conductivity better than all but the purest diamond, and electrical conductivity similar to copper, but with the ability to carry much higher currents, they seem to be a wonder material. Carbon nanotubes can conduct heat as efficiently as most diamond, conduct electricity as efficiently as copper, and yet it is also a semiconductor.

Carbon nanotubes are one of the most extensively researched materials today which reveals numerous surprises. In types of nanotubes only carbon nanotubes will be covered in white paper. Carbon nanotubes were first noticed in the graphitic soot deposited on the negatively charged electrode used in the arc-discharge synthesis of fullness.[13] Single-walled nanotubes and Multi-walled nanotubes are microscopic rather than nanoscopic, i.e. greater than 100 nanometers. Carbon Nanotube Transistors exploit the fact that nm- scale nanotubes (NT) are ready-made molecular wires and can be rendered into a conducting, semiconducting, or insulating state, which make them valuable for future nanocomputer design. Carbon nanotubes are quite popular now for their prospective electrical, thermal, and even selective-chemistry applications.[14] The Synthesis of Carbon Nanotubes is Arc discharge, Laser ablation and Chemical vapor deposition (CVD). Carbon nanotubes are basically classified as Single-walled nanotubes (which have a single cylindrical wall), Multi-walled nanotubes (which have cylinders within cylinders), Nanothorus, carbon nanobuds, and Cup stacked carbon nanotubes.

7.1.Types of Carbon Nanotubes

7.1.1. Single-walled Carbon nanotubes

Single-walled nanotubes (SWNT) are those carbon nanotubes which have a diameter of nearly 1 nanometer, with a tube length that can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder. Single-walled nanotubes are the most likely candidate for miniaturizing electronics beyond the micro electromechanical scale currently used in electronics.[15] Single-walled nanotubes (SWNT) can be used for miniaturizing electronics beyond the micro electromechanical scale, electric wire, conductors, and used for intramolecular field-effect transistors (FET). Single-walled nanotubes are more pliable than their multi-walled counterparts and can be twisted, flattened and bent into small circles or around sharp bends without breaking.[16] Single-walled nanotubes have oft-quoted amazing properties because they are basically tubes of graphite and are normally capped at the ends, although the caps can be removed. The electrical behavior of carbon nanotubes usually relate to experiments on the single-walled variety. Single-walled nanotubes are more complex in its structures and required tremendous care when it is in its developing process. To gain greater control over their diameters, lengths, and other properties, such as chirality is the main concerned of the Single-walled nanotubes producers today.

7.1.2. Multi-walled Carbon nanotubes

Multi-walled nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphite and. Mainly there are two models of Multi-walled nanotubes they are the Russian Doll model, in which the sheets of graphite are arranged in concentric cylinders, and the Parchment model, in which a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled newspaper. Multi-walled nanotubes are 100 times longer, wide, have an outer diameters, greater complexity and variety comparing to Multi-walled nanotubes. However, Multi-walled nanotubes have more defects than Single-walled nanotubes and these diminish their desirable properties. Multitudes of exotic shapes and arrangements, often with imaginative names such as bamboo-trunks, sea urchins, necklaces or coils, have also been observed under different processing conditions.[17] For practical purposes Multi-walled nanotubes are easier to produce in large quantities, at a reasonable price and have been available in decent amounts comparing to Single-walled nanotubes. The telescopic motion ability of inner shells and their unique mechanical properties permit to use multi-walled nanotubes as main movable arms in coming nano-mechanical devices.[18] Multi-walled nanotubes are formed with significant quantities of carbonaceous material. One of the way of separating the tubes from the carbon mass is to heat-treat the product.[19] Hyperion Catalysis, Mitsui are some of the companies that produces Multi-walled nanotubes.

7.1.3. Nanotorus

When carbon nanotubes are bent into a torus (doughnut shape) then they are known as Nanotorus. Nanotori are predicted to have many unique properties, such as magnetic moments 1000 times larger than previously expected for certain specific radii. Properties such as magnetic moment, thermal stability, etc. vary widely depending on radius of the torus and radius of the tube.[20]

7.1.4. Carbon nanobuds

Carbon nanobuds is a hybrid materials which combines together carbon nanotubes and fullerenes. In carbon nanobuds the fullerene-like ‘buds’ are join together with the outer sidewalls of the underlying carbon nanotube. In composite materials, the attached fullerene molecules may function as molecular anchors preventing slipping of the nanotubes, thus improving the composite’s mechanical properties.[21] Carbon nanobuds have been found to be exceptionally good field emitters.

7.1.5. Cup stacked carbon nanotubes

Cup-stacked carbon nanotubes (CSCNTs) differ from other quasi-1D carbon structures, which normally behave as quasi-metallic conductors of electrons. They exhibit semiconducting behaviors due to the stacking microstructure of graphene layers.[22]

7.2. Properties of Carbon Nanotubes

Carbon nanotubes are very complex in structures and is made of strong, stiff, soft materials and possesses tensile strength and elastic modulus respectively. The properties of Carbon nanotubes include Hardness, Kinetic, Electrical, Optical, Thermal, Defects, One-dimensional transport and Toxicity. Carbon nanotubes are so hard that it can withstand a pressure up to 24GPa without deformation. The Kinetic aspects of Carbon nanotube is revealed when Multi-walled nanotubes exhibit a striking telescoping property whereby an inner nanotube core may slide, almost without friction, within its outer nanotube shell, thus creating an atomically perfect linear or rotational bearing. The symmetry and unique electronic structure of graphene, the structure of a nanotube strongly affects its electrical properties.[23] Carbon nanotubes are good thermal conductors along the tube and posses a property known as “ballistic conduction”. Carbon nanotubes have a defect which is known as Stone Wales defect due to the existence of a crystallographic defect which occurs in the form of atomic vacancies. Carbon nanotubes are frequently referred to as “one-dimensional” because of the nanoscale dimensions, electrons propagate only along the tube’s axis and electron transport involves many quantum effects. Carbon nanotubes are highly toxic because it involves many combinations of chemicals which are toxic and non toxic.

Application of Nanotubes

Nanotubes have tremendous impact on different fields some of the most prominent potential applications are in Structural design, electrical circuits, electrical cables and wires, paper batteries, Solar cells, Ultra capacitors, Medical, Education and other applications. The strength and flexibility of carbon nanotubes makes them of potential use in controlling other nanoscale structures, the superior mechanical properties of carbon nanotubes makes it possible to prepare varied materials like like clothes and sports gear to combat jackets and space elevators and nanotubes are also building blocks in bio-mimetic hierarchical composite materials because of their exceptional mechanical properties. Carbon nanotubes are also use as electrical cables and wires, paper batteries, solar cells, ultra capacitors, LCD (liquid crystal display) TVs, computer disk drives. The application of Nanotubes is possible to soar very high impacting a wide variety of industries from sports equipment to furniture, from the construction industry to kitchenware, and from automobiles to airplanes and spacecraft. Nanotubes are the ultimate high strength carbon fibers. It is possible to construct a heterojunction by having a junction between nanotubes of different helicities. This approach facilitiates the creation of a device with one molecule.[24] Nanotubes tips can be used for nanoprobes. Nanotubes have been used for various metallocenes such as ferrocene, cobaltocence and nickelocene. In recent times application of nanotubes in CNT-based field emission displays is of great interest in commercial world. One of the most promising applications of nanotubes is a thin panel called a field emitter display (FED). Depending on the charge, the flexible nanotube can bend upward, away from the electrode, or downward, into contact with the electrode. The nanotube-based memory can act like “flash” memory, a reprogrammable type of memory that can retain data even when power is switched off.[25] The characteristics such as increased surface area along with enhanced electrical, optical properties make nanotubes suitable for numerous applications such as nanoelectronics, photovoltaics and chemical, biological sensing. When the spinal cord receive trauma, the brain and the body are often cut off from each other by the lack of nerve signal transmission along the spinal cord but Nanotubes have actually been proven to be able to correct this problem in some patients.[26] Nanotubes have tremendous impact in the fabrication of multiple sensors. Nanotubes are a proving to be useful as molecular components for nanotechnology.

Conclusion

In nanotechnology a nanotube is a long, cylindrical carbon structure consisting of hexagonal graphite molecules attached at the edges which was developed from Fullerene by R. Buckminster Fuller. Nanotubes are of different designed some may have single concentric cylinders while others may have multiple concentric cylinders with different wall thickness, number of concentric cylinders, cylinder radius, and cylinder length. Nanotubes have the potential for making ultra-strong fabrics as well as reinforcing structural materials in buildings, cars and airplanes and in the future nanotubes may replace silicon in electronic circuits, and prototypes of elementary components have been developed. Nanotubes might be used to build microscopic resistors, capacitors, inductors, diodes, or transistors. Nanotubes have an amazing potential in a wide variety like in Field Emission Display (LED), Conductive plastics, Conductive adhesives & Connectors, Molecular electronics, Energy storage, Thermal materials (conduct or insulate), Structural composites (Boeing 787,buildings,etc), Catalytic & biomedical supports, Medical sciences, electronics engineering, optical technologies, nanotechnology, materials engineering and many others. Nanotubes have made a difference in science and technology in the past and present and it will continue to show wonders in the future. Science and technology with the development of nanotechnology will continue to have a tremendous impact in human life and in Cosmos. Nanotubes are dream come true in Science and Technology and make people in this world to live happier, easier, longer and better than the past life.

References

[1]Poorvi Dutta&Sushmita Gupta; Nano Science and Technology, pg. 5

[2]en.wikipedia.org/wiki/Nanotechnology

[3]IGNOU; Philosophy of Technology, pg. 29

[4]Poorvi Dutta&Sushmita Gupta; Nano Science and Technology, pg. 40

[5] T. Pradeep; NANO: The essentials, pg. 118

[6] http://www.edinformatics.com/interactive_molecules/fullerene.htm

[7] http://en.wikipedia.org/wiki/Carbon_nanotube

[8]http://www.answers.com/topic/chiral-nanotube#ixzz1ZKiDc1XP

[9]http://en.wikipedia.org/wiki/Membrane_nanotube

[10]http://en.wikipedia.org/wiki/nanotube

[11]http://en.wikipedia.org/wiki/Inorganic_nanotube

[12]http://en.wikipedia.org/wiki/DNA_nanotechnology

[13] T. Pradeep; NANO: The essentials, pg. 117

[14] http://www.nanotech-now.com/nanotube-buckyball-sites.htm

[15]http://en.wikipedia.org/wiki/Carbon_nanotube

[16] http://nanoparticles.org/pdf/nanotubes.pdf

[17] http://nanoparticles.org/pdf/nanotubes.pdf

[18] http://en.wikipedia.org/wiki/Carbon_nanotube

[19] T. Pradeep; NANO: The essentials, pg. 119

[20] http://en.wikipedia.org/wiki/Carbon_nanotube

[21] http://en.wikipedia.org/wiki/Carbon_nanotube

[22] http://en.wikipedia.org/wiki/Carbon_nanotube

[23] http://en.wikipedia.org/wiki/Carbon_nanotube

[24] T. Pradeep; NANO: The essentials, pg. 123

[25] http://www.edinformatics.com/interactive_molecules/fullerene.htm

[26] http://nanogloss.com/nanotubes/what-are-the-nanotubes-used-for/#axzz1ZhN1hGdb

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11. http://en.wikipedia.org/wiki/Membrane_nanotube accessed on 1/10/2011.

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