Part 3. Texts on interdisciplinary research for abstracting and annotating

Interdisciplinary research (IDR) now receives a great deal of attention because of the rich, creative contributions it often generates. But a host of factors — institutional, interpersonal, and intellectual — also make a daunting challenge of conducting research outside one's usual domain. This selection of the texts on interdisciplinary research is our brief guide to the most effective avenues for collaborative and integrative research in different spheres of knowledge.

It provides answers to questions such as what the best way is to conduct interdisciplinary research on topics related to humanitarian issues. Which are the most successful interdisciplinary research programs in these areas? How do you identify appropriate collaborators? How do you find dedicated funding streams? How do you overcome peer-review and publishing challenges? The selection outlines the lessons that can be taken from the IDR study, and presents a series of informative texts revealing the most successful interdisciplinary research ideas and programs. These programs provide a variety of models of how best to undertake interdisciplinary research.

TASKS

· Write synopses and/or annotations in Russian for each of the texts referring to the guidelines for synopses and annotations (appendix 10).

· Discuss the benefits of interdisciplinary research and the central strategies required to achieve them.

· Propose interdisciplinary research in your sphere of knowledge.

Carbon nanotubes: strengths, weaknesses, opportunities and threats

NANO Magazine, Wednesday, 13 October 2010, Issue 20 (http://www.nanomagazine.co.uk/)

Carbon nanotubes hold great promise for adding functionality, conductivity and strength to many existing and future products. For that reason they've become a hot topic for industry, with promised applications across a broad range sectors.

What are Carbon nanotubes?

Carbon nanotubes (CNTs) are allotropes of carbon. A single wall carbon nanotube is a one-atom thick sheet of graphite (called graphene) rolled up into a seamless cylinder with diameter of the order of a nanometer. This results in a nanostructure where the length-to-diameter ratio exceeds 10,000.

Such cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electronics, optics and other fields of materials science. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Inorganic nanotubes have also been synthesized. Nanotubes are members of the fullerene structural family, which also includes buckyballs. Whereas buckyballs are spherical in shape, a nanotube is cylindrical, with at least one end typically capped with a hemisphere of the buckyball structure. Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers (approximately 50,000 times smaller than the width of a human hair), while they can be up to several millimeters in length.

There are two main types of nanotubes: single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs). Single-walled carbon nanotubes consist of one graphite sheet tube of carbon atom hexagons, while multi-walled carbon nanotubes are characterized by multiple concentric tubes both have a diameter of 1 to 100 nanometres, but average at just a few nanometres. Although not a hollow tube, carbon nanofibers (CNF) represent a third type of tubular structure. The ends of nanotubes are either open or capped with fullerenes.

The nature of the bonding of a nanotube is described by applied quantum chemistry, specifically, orbital hybridization. The chemical bonding of nanotubes are composed entirely of sp2 bonds, similar to those of graphite. This bonding structure, which is stronger than the sp3 bonds found in diamond, provides the molecules with their unique strength. Nanotubes naturally align themselves into "ropes" held together by Van der Waals forces. Under high pressure, nanotubes can merge together, trading some sp2 bonds for sp3 bonds, giving great possibility for producing strong, unlimited-length wires through high-pressure nanotube linking.

They are not unlike other carbon materials, such as diamond or the carbon black that can be found in pencils or car tyres. They have a completely different structure, however, which gives them interesting and very promising properties. Normal graphite is built of sheets with a honeycomb structure of carbon atoms. These sheets are very strong, stable and flexible, but adjoining sheets lack a strong cohesion. In nanotubes, however, these sheets are larger and are “rolled-up” to form long, thin spiral patterns. The significant interest in the production, research and development of carbon nanotubes stems from the unique chemical, mechanical, and physical properties inherent in these materials as. These desired properties include high tensile strength, high electric and thermal conductivity, lightweight, high surface area per gram, advantages in hydrogen storing and catalyzing, absorbency, and flexibility.

The tensile strength of single-walled nanotubes is 100 times greater than that of steel, at only one sixth of steel weight. In terms of thermal conductivity, carbon nanotubes at 1,200-3,000 W/mK exceed that for diamonds at 700-2,000 W/mK. Because of these properties, many researchers and product developers have been attracted to carbon nanotubes for a broad array of potential applications including composites, displays, sensors, fuel and solar cells, batteries, and pharmaceutical materials.

Production and Synthesis

The Chemical Vapor Deposition (CVD) technique is the most commonly used for making nanotubes. Companies such as CNRI, Nanocyl, NanoLab, Nanoamor, and Shenzhen Nanotech use CVD; MER, Nanocarblab, NanoLedge use arc discharge; ILJIN uses both CVD and arc discharge. The production methods have not yet been mastered and thus nanotubes have yet to be produced in mass quantities. Some SWNT producers may be moving away from the older methods and using fluidized beds and other high throughput methods, in order to scale production with relatively low costs.

Raymor Industries utilises a hybrid of existing CVD and Arc processes which uses specially designed plasma torch (design cannot be revealed for competitive reasons) to explode molecules in highly efficient way. It is a clean process; there is no emission of toxic gas. Hydrogen molecules can be recycled for environmental purposes. The process creates a large quantity of nanotubes compared to the original mass. The single-walled nanotubes formed are of a high quality and high purity.

Depending on the method of synthesis, impurities in the form of catalyst particles, amorphous carbon, and non-tubular fullerenes are also produced. Thus, subsequent purification steps are required to separate the tubes from other forms of non-tubular carbon. Purification involves chemical processes like acid reflux, filtration, centrifugation, and repeated washes with solvents and water. Typical nanotube diameters range from 0.4 to 3 nm for SWNTs, and from 1.4 to more than 100 nm for MWNTs. It has been established that a nanotube's properties can be tuned by changing its diameter.

Market Hype

The main driving force for investment in carbon nanotubes R&D is their promise to offer improvements in materials capabilities across a wide range of applications. This is of huge strategic importance to sectors which historically leverage technological advancements. Carbon nanotubes enable radical design changes for a wide variety of markets by permitting combinations of properties not previously possible in materials design and affording multi-functionality for increased efficiency. The challenge is translating the excellent combination of nanotubes properties on the nanoscale to structural properties on the macroscale. Current hindrances include: inconsistent quality of carbon nanotubes supply; dispersion; characterization of carbon nanotubes nanocomposites; and scaling down processing equipment to work around the low CNT supply.

The majority of current global revenues for carbon nanotubes are generated by relatively large-scale manufacturing of bulk materials for applications where electrical conductivity, increased mechanical performance and flame retardancy are primary design drivers. Composites, field emission devices and batteries are the most prominent and commercially viable current applications. Next generation products will incorporate sensing capabilities and multi-functionality and lead to greatly increased revenues over the next 3-10 years. Prices will also fall over the next few years as large companies begin to produce commercial-scale volumes of nanotubes. Large multi-nationals such as Arkema, Bayer and Showa Denko have significantly ramped up production levels; companies in China and Russia are also producing significantly cheaper nanotubes.

Main markets at present for nanotubes are aerospace, automotive, defence and electronics & data storage; generally as multi-purpose compound enhancers. In aerospace, nanotubes already find application as additives for ESD and EMI shielding; as electrostatic coatings and component reinforcement additives in the automotive sector; in various defence applications; and as conductive polymers and composites for field emission displays. This represents the first generation of nanotubes products; the next generation will be based on controlled fabrications leading to multi-functional and sensory capabilities.

The electronics and data storage market is likely to see the biggest penetration to 2015, with the performance enhancing properties of carbon nanotubes allowing electronics manufacturers to meet demanding market needs across a variety of applications. Their incorporation into the displays applications will also increase demand, with a conservative revenue forecast of $1.07 billion by 2015.

There is a great demand in the market for carbon nanotubes, especially in the electronics and polymers sectors; production and price are restraints at present but this is changing. A kilogram of carbon nanotubes used to cost up to $1,000, but now, as a result of targeted research and development activities, companies has managed to significantly lower the price-per-kilogram, thereby enabling the development of new, industrial applications. For example, the automotive industry will soon be able to reduce the cost of painting plastic fenders: adding just minimal amounts makes the semi-finished parts electrically conductive, and this new material property supports more efficient and environmentally friendly coating processes based on counter charged, solvent-free powder coating particles.

In most cases, CNTs are used as an additive to add value to existing products or to develop new products such as Field Emission Displays displays. The advantage as an additive is usually an enhancement of the properties with a low loading of nanotubes. This low loading also offers new possibilities like transparency in coatings. Other advantages can be lower manufacturing cost using a CNT-based technology.

One of the biggest challenges facing the carbon nanotube producers is the ability to obtain significant quantities of the desired type of carbon nanotube. High throughput experimentation is one possible approach that holds promise for searching the best catalyst for growing the desired nanotube. Other issues that assume significant importance is identifying the most likely nanomaterial and then setting up a large infrastructure for a scalable mass-manufacturing process. Some techniques that are used to build electronic components with carbon nanotubes are inappropriate for mass production.

Expensive, small scale production of nanotubes as well as clumping, lack of binding to the bulk material, and temperature effects are therefore key barriers to their application in the industry. Although there are challenges ahead, carbon nanotubes have opened up a host of practical applications in the nanometre scale.

Applications of CNTs

Examples of carbon nanotube-based applications are illustrated in the roadmap. The main markets for nanotubes at present are aerospace, automotive, defence and electronics & data storage; generally as multi-purpose compound enhancers. In aerospace, nanotubes already find application as additives for ESD and EMI shielding. The automotive sector uses them as electrostatic coatings and component reinforcement additives. in various defence applications; and as conductive polymers and in consumer electronics such as composites for FED. This represents the first generation of nanotubes products; the next generation will be based on controlled fabrications.

The ITC market is likely to see the biggest penetration to 2015, with the performance enhancing properties allowing electronics manufacturers to meet demanding market needs. Their incorporation into the displays market will increase demand by 2010, with a revenue forecast in the ITC market of $1.096 billion by 2015. While in the longer run, electronics will continue to dominate nanotube applications as broader use in semiconductors occurs, strong opportunities are also expected from CNT-based products using chemical vapour deposition technology.

It seems the possibilities for carbon nanotubes will continue to develop in the future as research continues to develop on their possibilities. Researchers at the University of Cincinnati (UC) have developed a process to build extremely long aligned carbon nanotube arrays. They've been able to produce 18-mm-long carbon nanotubes which might be spun into nanofibers.

New studies on the strength of these submicroscopic cylinders of carbon from the University of Southern California, LA, indicate that on an ounce-for-ounce basis they are at least 117 times stronger than steel and 30 times stronger than Kevlar, the material used in bulletproof vests and other products. That's twice as strong as they were once thought to be – it seems the future's brighter and stronger for carbon nanotubes.

Prizewinning nanoparticle based ‘sharkskin’ for aeroplanes, ships and wind energy plants

NANO Magazine, 2010, Issue 18 (http://www.nanomagazine.co.uk/)

To lower the fuel consumption of airplanes and ships, it is necessary to reduce their flow resistance, or drag. An innovative paint system makes this possible. This not only lowers costs, it also reduces CO2 emissions.

The inspiration – and model – for the paint‘s structure comes from nature: The scales of fast-swimming sharks have evolved in a manner that significantly diminishes drag, or their resistance to the flow of currents. The challenge was to apply this knowledge to a paint that could withstand the extreme demands of aviation. Temperature fluctuations of -55 to +70 degrees Celsius; intensive UV radiation and high speeds. Yvonne Wilke, Dr. Volkmar Stenzel and Manfred Peschka of the Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research IFAM in Bremen developed not only a paint that reduces aerodynamic drag, but also the associated manufacturing technology. In recognition of their achievement, the team is awarded the 2010 Joseph von Fraunhofer Prize.

The paint involves of a sophisticated formulation. An integral part of the recipe: the nanoparticles, which ensure that the paint withstands UV radiation, temperature change and mechanical loads, on an enduring basis. „Paint offers more advantages," explains Dr. Volkmar Stenzel. „It is applied as the outermost coating on the plane, so that no other layer of material is required. It adds no additional weight, and even when the airplane is stripped – about every five years, the paint has to be completely removed and reapplied – no additional costs are incurred. In addition, it can be applied to complex three-dimensional surfaces without a problem." The next step was to clarify how the paint could be put to practical use on a production scale. „Our solution consisted of not applying the paint directly, but instead through a stencil," says Manfred Peschka. This gives the paint its sharkskin structure. The unique challenge was to apply the fluid paint evenly in a thin layer on the stencil, and at the same time ensure that it can again be detached from the base even after UV radiation, which is required for hardening.

Yvonne Wilke, Dr. Volkmar Stenzel and Manfred Peschka engineered a paint system that can reduce the fl ow resistance of airplanes and ships. That saves fuel.

When applied to every airplane every year throughout the world, the paint could save a volume of 4.48 million tons of fuel. This also applies to ships: The team was able to reduce wall friction by more than five percent in a test with a ship construction testing facility. Extrapolated over one year, that means a potential savings of 2,000 tons of fuel for a large container ship. With this application, the algae or muscles that attach to the hull of a ship only complicate things further. Researchers are working on two solutions for the problem. Yvonne Wilke explains: „One possibility exists in structuring the paint in such a way that fouling organisms cannot get a firm grasp and are simply washed away at high speeds, for example. The second option aims at integrating an anti-fouling element – which is incompatible for nature."

Irrespective of the fuel savings, there are even more interesting applications – for instance, with wind energy farms. Here as well, air resistance has a negative effect on the rotor blades. The new paint would improve the degree of efficiency of the systems – and thus the energy gain.