The World of
Nanoparticles
People love
gigantic things. Giant machines, for example, make us feel we control the world and can
change it to suit our own designs. Anyone who has stood close to a brown-coal excavator in
an open-cast mine knows this feeling. However, big changes can also be achieved with
mini-machines – in the microcosm. This move into the microcosm began with computer
technology. Ever smaller structures – strip conductors and transistors – were
crammed onto silicon chips, enabling us carry out ever faster operations in the digital
world. Then we started combining the electronic part with sensor technology on the chips.
For example, tiny fluctuating structures were etched into the chips to measure
accelerations. The staying power of these small masses was enough to control processes in
the macro world: for example to initiate the inflation of an airbag when a car crashes. In
another case, the tiny structures on a chip can form the elements of an artificial nose.
Certain molecules dock onto a wafer or tongue, depending on what substance it is coated
with; this makes these mobile tongues heavier, bending them accordingly, and tells the
electronic systems how much of a certain substance there is in the air.
In this
microcosm, today we are even able to arrange individual atoms and molecules in a specific
way. In other words, we have arrived in the nanoworld. Nanos comes from the Greek and
means dwarf. Scientifically, it means the range within a billionth of a metre. In this
world, fine metal points scan surfaces and measure the changes in the electrical field
caused by the atoms. In other words, individual atoms can be "seen." Conversely,
by applying a voltage from outside we can place individual atoms or molecules onto these
surfaces and arrange them as we wish. To this extent, we have come closer to the vision of
building nanodevices. These ideas have inspired several adventures in movies, with
mini-robots floating through our body’s arteries and repairing faults: breaking up
blood clots or patching up broken artery walls. Some of the things that really are
possible today include mini-pumps integrated into chips, motors etched into wafers, and
the precursors of molecular drives, which have been copied from micro-organisms.
The nanoworld is
always good for surprises. The forces acting on the individual parts are largely
determined by the attraction between the molecules themselves. As a result, the classical
scientific laws on how liquids flow no longer fully apply here, and friction gains a
completely different significance. However, if we can deliberately change materials even
at atomic dimensions, then new effects can be achieved. For example, we are already making
car paints more scratchproof by adding individual molecules; there is a skin just a few
nanometres thick enclosing microcapsules of fragrances which, when sprayed onto a car
seat, break when sat on, giving off their pleasant smells; and tubular structures on a
nanoscale made of carbon atoms, when added in the right amounts, can make plastics
electrically conductive and form the basis for a new type of screen (electrons can be shot
with precision from the nanotubes – an important condition for a fluorescent screen).
Ongoing research into the nanoworld is opening up more and more new possibilities. For
example, semiconductor crystals – known as quantum points – can be made on a
molecular scale which light up when exposed to laser light. They are attached to genes or
proteins as "markers," enabling us to trace the movements of individual
biomolecules within a living cell. In future, we hope to deliver certain medicines in the
form of nanoparticles straight to diseased tissue in the body, where they can have their
healing effect. Of course, you need the right tools to be able to handle individual atoms
or molecules. The decisive invention that makes that possible in the nanocosm is the
Raster Tunnel Microscope. It consists of the above-mentioned fine metal points enabling
scientists to scan surfaces and change the position and arrangement of individual atoms.
The German
physicist Gerd Binnig was awarded the Nobel Prize for Physics in 1986 for the development
of this Raster Tunnel Microscope. Nanotechnology has made rapid strides ahead since this
important achievement; here, too, German researchers are playing a crucial role in various
laboratories. July 26, 2004 (Text Courtesy: Deutschland Magazine, Embassy of Germany,
Nepal)
World
Bank report examines trade regimes in South Asia
South Asian economies can benefit from further trade policy reform
Dhaka, November
8, 2004 — A new World Bank report suggests that the poor of South Asia would be among
the significant beneficiaries of wider and faster trade liberalization in the region. The
Trade Policies in South Asia: An Overview, released today in Dhaka, describes key aspects
of the current trade regimes in the five largest South Asian countries and concludes that,
despite progress towards liberalization, protectionist forces are still strong in the
region hampering growth and poverty reduction.
The report looks
into key aspects of the current trade regimes in Bangladesh, India, Nepal, Pakistan, and
Sri Lanka, and offers recommendations on some of the key issues facing policymakers on
trade reform. The report is the first comprehensive review of South Asian trade regimes,
examining policies within the countries and in light of the global context.
"Trade
policies of the South Asian countries are now much more open than they were in the
past," says Zaidi Sattar, task manager and coauthor of the report. "Most
non-tariff barriers to imports have been removed and tariffs substantially reduced. Even
though comprehensive trade liberalization reforms have been implemented in all of the
countries, protection and protectionist forces are still strong and a difficult and
challenging trade policy reform agenda lies ahead."
Trade regimes are
examined in their current state, their evolution over the past decade or so, and their
future directions. The report provides a comprehensive overview of some of the major
issues facing progress in the region, including agricultural subsidies and preferential
trading arrangements.
The report
reviews the current status of trade openness on a country-by-country basis, with
particular focus on tariffs, non-tariff barriers, anti-dumping, and export policies. Also
featured are trade policies affecting key sectors like agriculture, fertilizers, and
textiles and clothing. The report notes, for example, that one broad area of notable
advance which has facilitated trade expansion in the region is the move towards more
market-based exchange rate regimes. On the other hand, tariffs are now the principal means
by which the South Asian countries protect their domestic industries.
"On average,
tariffs are much lower than they were in the past, but they are still too high when
considered in the global context" says Garry Pursell, lead consultant for the report.
"In India and Bangladesh, there was some backtracking on tariff reform between about
1997 and 2001, but tariff reductions resumed in 2002, with substantial lowering of rates
in 2004. Pakistan implemented a sweeping tariff reduction and simplification program
between 1997 and 2002. Sri Lanka’s trade policy reforms came much earlier than in the
rest of South Asia, and on average its tariffs are by far the lowest in the region, with
the important exception of high tariffs protecting its import substitution agricultural
sector."
The report has
been prepared following several workshops held in the South Asia region in the past year
to elicit feedback and comments from policymakers, development practitioners, academics,
and business leaders who participated in those workshops.
INDOOR
AIR POLLUTION
THE KILLER IN
THE KITCHEN
The World Health
Organization (WHO) and the United Nations Development Programme (UNDP) are marking World
Rural Women’s Day on 15 October 2004 by drawing attention to indoor air pollution -
one of the major causes of death and disease in the world’s poorest countries. While
the millions of deaths from well-known communicable diseases often make headlines, indoor
air pollution remains a silent and unreported killer. Rural women and children are the
most at risk.
Thick acrid smoke
rising from stoves and fires inside homes is associated with around 1.6 million deaths per
year in developing countries - that’s one life lost every 20 seconds to the killer in
the kitchen.
Nearly half of
the world continues to cook with solid fuels such as dung, wood, agricultural residues and
coal. Smoke from burning these fuels gives off a poisonous cocktail of particles and
chemicals that bypass the body’s defences and more than doubles the risk of
respiratory illnesses such as bronchitis and pneumonia.
The indoor
concentration of health-damaging pollutants from a typical wood-fired cooking stove
creates carbon monoxide and other noxious fumes at anywhere between seven and 500 times
over the allowable limits
(see table
below).
Day in day out,
and for hours at a time, rural women and their children in particular are subjected to
levels of smoke in their homes that far exceed international safety standards. The World
Energy Assessment (1) estimates that the amount of smoke from these fires is the
equivalent of consuming two packs of cigarettes a day - and yet, these families are faced
with what amounts to a non-choice - not cooking using these fuels, or not eating.
Rural women and
their families also pay a high economic price for keeping the fire burning. Up to three
mornings a week are spent collecting fuel such as wood. This perpetual toil denies poor
rural women the chance to be more productive through paid work that would raise their
family’s income, improve the standard of living and enhance their nutritional and
health status. And in the crisis-stricken Darfur region of Sudan, the chore has taken on a
perilous dimension following the rape, kidnap, beatings and murder of women leaving
refugee camps to search for wood.
So what can be
done to put an end to indoor air pollution? Finding cleaner solutions is the main
challenge. Gases, liquids and electricity are the main alternatives. Although today these
energy sources derive mainly from fossil fuels, this needs not be the case in the future
when renewable energies may ease the pressure on natural ecosystems. Other steps include
the recognition and action by governments, the aid community, civil society and other key
actors that indoor smoke is a huge blight on the lives of rural women and their children.
Two years ago, at
the World Summit on Sustainable Development (WSSD) in Johannesburg the Global Partnership
for Clean Indoor Air was launched with the backing of WHO and the international community.
As such, a growing network of experts and organizations are responding to the challenge by
finding innovative and affordable solutions that deploy cleaner stoves, fuels and smoke
hoods. Their implementation will require the development of viable and sustainable
markets, as created through the Liquefied Petroleum Gas (LPG) Rural Energy Challenge for
LPG delivery and consumption, a public-private partnership including UNDP, also
established at the WSSD. But this is just the beginning. WHO recently published the
first-ever comprehensive Atlas of Children’s Environmental Health as a means of
drawing attention to and increasing support for reducing indoor air pollution (and other
environmental health issues). We need the same attention paid to this "killer in the
kitchen" as is paid to other major killers.
Note: using 1 Kg
of wood/hour in 15 ACH 40 m3 kitchens emits, among other pollutants, the following:
Pollutant
Emission (mg/m3) Allowable standard (mg/m3)
Carbon Monoxide
150 10
Particles 3.3 0.1
Benzene 0.8 0.002
1,3-Butadiene
0.15 0.0003
Formaldehyde 0.7
0.1
Source: Based on
the UNDP/DESA/WEC World Energy Assessment
(Courtesy: World
Health Organization) |
