Nanotech shines: Rice University researcher Yao Zhao demonstrates a setup that uses a carbon nanotube cable to carry standard electrical current to a fluorescent lightbulb.
Credit: Rice University

ENERGY

Nanotube Cables Hit a Milestone: As Good as Copper

Researchers achieve a goal they've been after since the 1980s—the advance could make cars and airplanes lighter, and renewable energy more practical.

• BY KATHERINE BOURZAC

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For the first time, researchers have made carbon-nanotube electrical cables that can carry as much current as copper wires. These nanotube cables could help carry more renewable power farther in the electrical grid, provide lightweight wiring for more-fuel-efficient vehicles and planes, and make connections in low-power computer chips. Researchers at Rice University have now demonstrated carbon-nanotube cables in a practical system and are designing a manufacturing line for commercial production.

Making lightweight, efficient carbon nanotube wiring as conductive as copper has been a goal of nanotechnologists since the 1980s. Individual carbon nanotubes—hollow nanoscale tubes of pure carbon—are mechanically strong and an order of magnitude more conductive than copper. But unless carbon nanotubes are put together just so, larger structures made from them don't have the superlative properties of the individual tubes.

Years of tinkering in the lab to find the right assembly techniques and ingredients have enabled researchers led by Rice materials science professors Pulickel Ajayan and Enrique Barrera to finally make carbon nanotube cables as good as copper cables. The group's nano cables boast a combination of properties that's so far unprecedented. They're mechanically strong, yet flexible enough to be knotted or woven together into long lengths of wire. They carry about 100,000 amps of current per square centimeter of material, about the same amount as copper wires, but weigh one-sixth as much. They outperform copper on a metric called current density, which means they should be able to carry more electricity over longer distances without losing energy to heat—a problem with today's electrical grid, and with computer chips. And because they're made of carbon, not metal, they don't corrode.

Carbon nanotubes vary in their conductivity, length, and number of layers. The Rice group found that what worked best were relatively long, double-walled nanotubes provided by collaborators from Tsinghua University in Beijing. Electrons move through individual nanotubes very quickly, but current slows down when the electrons must jump from nanotube to nanotube. The longer the nanotubes, the fewer such jumps the electrons have to make in a given length of wire.

The process of making nano cables begins with a lump of double-walled nanotubes that have been treated to remove impurities. The researchers add sulfuric acid to the nanotubes so they can spread them into a thin film. They then grasp the edge of the film with tweezers to start making a fiber, and pull with a steady force to yield a long cable—similar to how wool yarn is made by pulling and twisting fleece. They rinse the acid from the cable and expose it to iodine vapor at high temperatures. The iodine penetrates into the nanotubes within the cable and increases the cable's conductivity without compromising its mechanical properties. And the Rice group has shown that conductivity isn't affected when the cables are knotted together to make greater lengths.

To demonstrate that cables made in this way can transmit a standard line voltage, they used one to connect a fluorescent lightbulb to a wall socket and left the light on for days. This work is described online in the journal Nature Scientific Reports.

Nano cable: This cable, made of carbon nanotubes, can carry as much electrical current as a copper wire.
Credit: Rice University

"It is a testament to how mature these materials are becoming that they are able to measure conductivities that now exceed common metals," says Michael Strano, a professor of chemical engineering at MIT who was not involved with the work. Surpassing metals, he says, "represents a milestone."

"This is very exciting, especially considering the enormous importance of decreasing the weight of [electrical] cables in airplanes and cars" to improve fuel efficiency, says Ray Baughman, director of the NanoTech Institute and professor of chemistry at the University of Texas at Dallas. Baughman was not involved with the work.

Aerospace giant Boeing is among the companies supporting the Rice group. Other collaborators and supporters include Chevron, the U.S. Department of Energy, and NanoRidge Materials of Houston.

"The goal is to make an engineered product," says Rice's Barrera. "We believe what we've been able to do is scalable to continuous production methods." The group has mapped out how this would be done on a manufacturing line and is currently exploring commercialization with various companies, though they have not disclosed any deals.

Though the cables are now good enough to begin thinking seriously about commercial applications, Ajayan wants to make them even better. Ajayan notes that, so far, they've only tested the double-walled cables' ability to carry direct current, the kind that comes out of wall sockets and that's used to move electricity over short distances in an airplane, for example. Electricity is transmitted over long distances in the form of alternating current. A separate goal, Ajayan says, is to make the cables even more conductive than copper. One way to do this is to make workable cables from single-walled carbon nanotubes, which are inherently more conductive, but have been difficult to spin into fibers.

Concepts and Methods of Development Planning

 

Introduction

¬  despite many changes there is a general agreement that planning with or without a formal plan document can be very useful in conducting economic affairs of a country, provided certain conditions are met

¬  many advanced free-enterprise economies prove that for planning, heavy government and bureaucratic intervention isn’t always necessary

¬  governments play a minimal role in economic management and do regularly formulate plans to guide the conduct of their economic policies

¬  the alternative to planned development is total reliance on the market to allocate resources

¬  most policy analysts would recommend an approach that avoids both extremes of tight state control and too much reliance on the market

¬  this module aims to introduce the reader to the basic concepts and methods of development planning, which is a specialised subject

Development Planning- International Experience

¬  over the past four decades developing countries in many parts of the world have prepared several development plans, spending vast amounts of resources to do so

¬  however initially they did not have the technical capacity to undertake such work, and so depended heavily on expatriate expertise

¬  in Eastern Europe, Asia and Northern Africa most socialist economies were inspired by the apparent success of the planned development in the former USSR, and so attempted to copy the plans

¬  Sub-Saharan Africa and the Caribbean were often influenced by their colonial rulers and were managed largely by expatriates; along with this external aid agencies also influenced the plans

¬  many of these type of plans however remained mere “show pieces” as they lacked domestic political support; this was also common in Latin America

¬  however the process of plan preparation has brought considerable “side benefits”, despite the lack of implementation, including understanding development problems, improved statistical data collection systems and a core of trained public officials

¬  some countries are motivated to create development plans to attract aid, and often meet these objectives even if the plans themselves are not fully implemented

¬  many countries in East Asia (Japan, the Republic of Korea, Taiwan and Singapore) developed a different, more pragmatic approach  to planned development; managing national resources so the focus is on comprehensiveness as well as having developed a unique partnership between the public and private sector

¬  other East Asian economies-Malaysia, Thailand and Indonesia followed a broadly similar approach

¬  since 1960 the eight “high performing Asian economies” (HPAE) listed, have achieved growth rates twice as high as the rest of East Asia and three times that of South Asia and Latin America

¬  they were also successful in spreading the fruits of growth among their population and so while the average income levels increased rapidly, the number of people living in poverty dramatically declined, as such the human development indicators increased

¬  thus it would appear that development planning appeared to work well in the East Asian area

Development Planning in Sri Lanka: A Chronology of Important Events

¬  Sri Lanka’s experience in development planning generally conforms to the pattern of the majority of developing countries, with no periodic plan actually being implemented as originally intended

¬  this however hasn’t been a wasteful exercise because during the process of plan preparation several side benefits have been brought

¬  over the last fifty years there have been planning experiments at the national level as well as plans being prepared and implemented at other levels such as sectoral plans and strategies/programmes and various regional plans

¬  the earliest sectoral/regional plans were perhaps those related to the various irrigation and colonisation schemes such as Minneriya and Gal Oya (1930s and 1940s)

¬  while a considerable amount of planning has occurred over the last five decades, their continuity had been adversely affected by frequent changes in institutional arrangements

Arguments For and Against Planning

¬  “resource allocation” concerns all decisions taken by numerous economic agents that affect not only the size but also the internal composition of the variables (investment, private consumption, government consumption, imports, and exports)

¬  there is a relationship between investment and growth of the economy that is fundamental to planning at the macro level- the level of investment undertaken during the current period determines the future growth of the economy

¬  the arguments for and against planning may be summarised as follows;

• market based allocation decisions may not address such broader and long- term social objectives and may lead to unfair distribution of incomes across income groups and geographical regions
• however, in practice governments have neither the necessary information and foresight nor the institutional capacity to formulate plans and implement them successfully
• therefore, planned development managed by the Government may lead to excessive controls and price distortions that retard economic growth. The end result may be worse than what would have occurred had there been no intervention
• given this reality, a developing country is best advised to work out an optimal balance between an ‘incomplete market’ and an ‘incomplete government’ to build a system appropriate to its own circumstances
• planning can, in principle lead to better allocation of resources that meet the long-term and broader social and economic objectives of a society

Development Plan- Components and Main Features

¬  a development plan is a way of setting out:

·         the development goals and objectives of the nation as identified by the Government in office and

·         a strategy for achieving these development goals and objectives

¬  in addition, a development plan can include several non-critical or peripheral features such as a situation analysis, priorities, plan targets and a monitoring and implementation scheme

¬  below are the objectives of an actual plan:

¬  despite many changes in our thinking on development issues since its publication, the methodology of the TYP and many of its findings remain generally valid even at present

Classification and Terminology of Development Plans

¬  a plan document is the outcome of a plan-preparation exercise

¬  there is an important difference between planning and plan-preparation; planning is a process of intervention in the economy in pursuance of perceived goals and objectives, while the planning process  involves centralised control of production, distribution and prices

¬  in planning the Government exercises a high degree of control over economic and social affairs and is often referred to as a “Command Economy”

¬  while the associated planning process is often referred to as “Dirigistic Planning”

¬  it should also be understood that planning, as described, can exist without any formal planning document

¬  several criteria maybe used to classify development plans, following are some types:

·         comprehensive plan:- covers all key sectors of the economy, placing considerable emphasis on maintaining balanced growth among the sectors

§  technical innovations were developed during the 1950s and 1960s to support such plans

·         partial or strategic plan-  is the alternative to a comprehensive plan , it addresses selected sectors, the emphasis being on developing certain lead sectors which will create conditions for other sectors to develop without too much intervention

§  Public Investment Programme is an example of a strategic plan

·         indicative plan- these provide only a forecast of the future state of  the economy as an attempt to guide the public and private sector agencies in their economic decisions

§  thus they are fundamentally different from comprehensive plans, and seem to be more like dirigistic plans

¬  plans can also be classified according to time periods, and it is possible for them to exist side by side

·         short-term plans- in general are concerned with economic management/stabilization including the conduct of fiscal and monetary policies (1-2 years)

·         medium-term plans- usually emphasize economic growth, income, and employment objectives which are to be achieved through appropriate policy reforms and investment programmes (5-6 years)

·         long-term plan (perspective plan)- incorporate a long-term vision for society and seek to achieve selected goals in accordance with it (10-20 years)

¬  classification can also be based on objectives, where again there are three classifications, which can also exit side by side, and are in fact  complementary

·         macroeconomic plan- provides an overall picture of the existing economic situation as well and indicators of the movement of the economy as a whole

§  it may also describe the strategy for achieving the plan objectives

§  these are generally short-term or medium-term plans

·         sectoral plan- sets forth objectives for a particular sector, and the necessary to achieve such objectives

§  usually medium or long term targets are set for production, employment, incomes, exports, savings and investment

§  preparation of sectoral plans are normally preceded by a detailed sectoral analysis

·         project plan- projects are very important for any development programme because they are the instruments that finally deliver development

§  careful planning prior to the actual launching of the project is essential to ensure maximum benefit is derived from eth resources

§  this applies to all projects equally

¬  the modern approach to project planning is often referred to as  a “project cycle”, which refers to a series of activities/stages involved in designing and implementing a project successfully

                                                         i.            identification

                                                        ii.            preparation

                                                      iii.            appraisal

                                                      iv.            implementation

                                                       v.            evaluation

¬  decisions on selection and design of projects are based on an analysis of costs to be incurred and benefits expected from the project

¬  planning and strategy: strategy is a part of the development plan, but not the plan itself

¬  a strategy normally involve selecting certain critical actions, making decisions on sequencing and timing to implement them, therefore a good development plan invariably includes all these elements

¬  therefore  a development strategy in a typical developing country may involve:      

o   selecting certain priority programmes and projects

o   making policy changes

o   determining time schedules for implementations

o   making suitable arrangements for coordination, monitoring and progress control

¬  planning and policy: the term policy is meaningful only when it is related to a subject

¬  it appears that the actual term “policy” refers to a way of “doing things” representing a choice of one of several possible ways

¬  they maybe classified in two broad groups:

o   economy-wide policies (e.g. monetary policy, fiscal policy, employment policy and wage policy)

o   sectoral policies (e.g. agricultural subsidy policy, health policy and university admissions policy)

¬  policy regime: when all polices are taken together they forma policy regime, or a policy environment

¬  policies have a quality dimension to them, however they can only be judged as good or bad in relation  to the objectives they seek to achieve, not in isolation

¬  at least two common criteria exist that may be used to judge the quality of a policy regime:

1.       al policies should unambiguously work towards the stated objectives

2.       all policies should be consistent

Properties of a Good Development Plan

¬  based on the experiences of countries that have followed a planned approach to development, we can draw some useful generalizations of desirable properties a development planning process should have

¬  they can be summarized as;

·         consultation- giving due consideration to the views and requirements of a  wide cross section of the society in plan preparation; often requiring qualitative judgments as analytical techniques are insufficient; this provided a way of informing the private sector of what government is doing

·         flexibility- adequate provision must be made to adjust targets and reorient the strategy mid-way through implementation, due to uncertainties in the external environment

·         selectivity- governments should be selective in the adoption of goals and instruments for best results

·         policy coordination- there is no prescription for institutional arrangement, though it is necessary for a successful development plan; each country has to develop its own mode depending on its specific socio-political circumstances

·         paying due attention to information collection and monitoring- information is crucial to any planning activity; policy makers need to know where they want to take the economy, as well as  where it currently stands, and this is only attainable via statistical data; monitoring being necessary during implementation, to ensure that planned activities make adequate progress towards the goals, again reliable statistical data becomes importantDownload: eType1.com/f.php?FThoii

 -Mr. S. A. Karunaratne