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Nanotechnology from an Industrial Ecology Perspective

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Posted by: Karl Ramjohn

There has been much discussion in recent times of the possible impacts on health and the environment, associated with the emerging field of nanotechnology, for example: 

Nanotechnology Not That Green

Nanotechnology’s Public Health Hazard

Nano-pollution: the next scare story?

The following research paper provides a substance-flow analysis (SFA) of carbon nano-tubes from an industrial ecology perspective

Lekas, D. 2005. Analysis of Nanotechnology from an Industrial Ecology Perspective Part II: Substance Flow Analysis of Carbon Nanotubes. Yale School of Forestry & Environmental Studies. November 2005; 22 pp.

Link to full paper —> http://www.nanotechproject.org/file_…ed%20part2.pdf

1. Introduction

The “next plastic,” the future for electronics, a new energy storage material. Such descriptors have been given to the nanomaterial carbon nanotubes. These carbon atom cylinders with diameters under 100 nanometers are quickly becoming the focus of significant research and production around the world. Many people estimate that we will see high penetration of carbon nanotubes into everyday products in the near future. At the same time, however, many have expressed concern over the potential health risks from exposure to nanotubes. In order to better understand the scope of nanotube production, use, and destiny, particularly in terms of their impacts in the environment and on human health, this paper presents findings from an investigation into the feasibility of performing a substance flow analysis on carbon nanotubes.

A substance flow analysis (SFA) is a study of the flow of specific materials throughout the economy from cradle to grave. This approach has been called “a tool for analyzing the societal metabolism of substances,”. It examines and attempts to quantify the inputs of a substance or material into production, end-use applications, and ultimately end-of-life phases. Insight into the material inputs and outputs and other detail at one level or stage (e.g., production) may influence findings at other levels.

A SFA can be an appropriate tool when the material of interest is linked to a particular impact and thus warrants a more focused analysis on the “stocks and flows” and “concentrations in the environment,”. Because of the potential environmental and health impacts of carbon nanotubes (pending their penetration into products and uses), I hypothesized that the SFA approach would help shed light on the uncertain impacts. More specifically, I suspected that information on the quantity of carbon nanotubes produced would better inform understanding on the application of these substances into end uses, and that end-use information would improve the understanding of potential consequences of carbon nanotubes to users and in the environment. 

2. Methodology
3. Nanotube Overview
4. Carbon Nanotube SFA Findings
5. Conclusions

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Recent News on Energy and the Environment 26.10.08

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Biomass Energy – Sustainable Solution to Livestock Wastes?

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Submitted by: Karl Ramjohn

Livestock production is an important food supply and economic activity, the primary goal of which is to supply high-quality protein (meat, eggs, dairy products, etc) for the needs of human populations. The animals serve as concentrated sources of typically dispersed nutrients. Subsidiary products may include leather, fertilizers, inputs to animal feeds, and energy sources (biofuels). The challenge of sustainable livestock production systems is to promote food security in a manner which is economically viable and socially acceptable without causing land degradation or irreversibly affecting ecological resilience. As such, sustainability must promote a favourable cost – benefit ratio, and as far as possible avoid reducing the set of options available to future generations. This has very significant social considerations, as seemingly obvious solutions may be difficult to implement, as they may be biologically but not economically sustainable.

The recycling of materials, and thus minimizing the generation of wastes is a basic process which must be implemented to meet the demands of sustainability in developed and developing countries alike. Systems which utilize energy produced from biomass are examples of energy-recycling systems. All biomass originates through carbon dioxide fixation by photosynthesis. Consequently, biomass utilization may be regarded as a critical component of the global carbon cycle of the biosphere.

Most biomass cannot be directly utilized, and must undergo some sort of transformation before being converted to fuel. Biological processes for the conversion of biomass to fuels include ethanol fermentation by yeast or bacteria, and methane production by microbial consortia under anaerobic conditions. Unlike ethanol fermentation, anaerobic digestion for methane production utilizes organic materials containing carbohydrates, lipids and proteins. Waste materials from livestock production are applicable to anaerobic digestion, with the added advantage of reducing environmental impacts, such as unpleasant odours and water pollution.

Methane fermentation is therefore a versatile biotechnology, which can convert almost all types of polymeric materials to methane and carbon dioxide under anaerobic conditions. It converts the waste products of livestock systems into useful products of commercial value, while reducing the environmental costs associated with other methods of livestock waste disposal. As such, it offers an effective means of pollution reduction, superior to that achieved by conventional aerobic processes. It is also an efficient method of converting unused biomass resources (crop residues, forestry, industrial/municipal and livestock wastes) into biofuels and fertilizers.

The digested slurry (by-product of methane production) retains the nitrogen and other mineral nutrients which are lost when biomass wastes are directly burned, while reducing BOD/COD. Methane is a principal constituent of natural gas, and extraction of this resource from livestock waste is a small-scale but useful method of supplementing extraction from geologic deposits. It also mitigates the problems associated with slow decomposition on the land surface, in the context of the large “greenhouse effect” of methane – up to 25 times that of carbon dioxide. The pathogens are also destroyed, reducing the health effects of the digested biomass, which also does not attract flies or rodents.

Biomass conversion is economically feasible within the constraints of scale and location. The main problems associated with biomass digestors is the relatively high price of implementation, the fact that the technology is still somewhat experimental, and the high standard of management and maintenance required.

Overriding issues in the future of biological energy systems are the overall efficiency of converting biomass to fuels, the economics of such processes, their environmental impacts, their competitiveness with thermochemical processes for biomass, and their compatibility with evolving economic and political structures.

Related:

http://tropicalenv.conforums.com/index.cgi?board=landuse04&action=display&num=1218573241

Integrated Food–Energy Systems (IFES)

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Submitted by: Karl Ramjohn

Our life on Earth depends on a dynamic complex of linkages, synergies and interactions among the processes, components and sub-systems of the atmosphere, hydrosphere, lithosphere and biosphere. The ecological view of sustainability focuses on the stability of biological and physical systems. Of particular importance is the viability of sub-systems that are crucial to the global stability of the overall ecosystem. Protection of biodiversity is a key aspect. Furthermore “natural” ecosystems may be interpreted to include all aspects of the biosphere, including man-made environments like intensive agriculture, cities and industrial estates. The emphasis is on preserving the resilience and dynamic ability of the totality of systems to adapt to change, rather than conservation of some “ideal” static state of the environment. Therefore, expansion of renewable bio-energy will require not only advances in technology, but also tangible economic accounting of their environmental and social benefits, compared to fossil fuels.

The development of sustainable, multi-purpose, integrated biomass conversion systems, is based on highly efficient photosynthesis and microbial processes, generating a number of products including energy resources (biofuels). Such systems have the potential for reducing the adverse impacts of agriculture and forestry, while providing food, fibre, pharmaceuticals and supplementary biofuels, to enhance the requirements for an acceptable standard of living. Energy production via biomass conversion of agricultural wastes reduces the environmental costs of food production systems, and provides economic benefit for the farmer, as well as reducing social impacts. As such, it provides a platform for integrating food and energy production in a sustainable manner.

The major social aims of Integrated Food – Energy Systems (IFES) is to maximize synergies between food crops, livestock, fish production and sources of renewable energy (e.g. biodigestion of wastes). This is achieved by adoption of agro-industrial technology that allows maximum utilization of by-products, diversification of raw materials, waste production on a smaller scale, and encouraging recycling and economic utilization of residues, for harmonization of energy and food production.

The essential features of IFES include:

• Using technology mix to provide a minimum cost alternative;
• Meeting energy needs not only for agriculture, but also other social needs (e.g. domestic, commercial, industrial);
• Maximizing utilization of available bio-resources with minimum environmental impact;
• Benefiting all classes of the community;
• Increasing food productivity;
• Generating additional income and employment opportunities; and
• Requirement of minimum maintenance to integrate community participation in management.

The design of IFES requires a simultaneous consideration of:

• The bio-physical components of resource management;
• The social and ecological impacts of technologies used; and
• The institutional settings involved

For each site-specific configuration of climatic and environmental conditions, several socially desirable, ecologically sustainable and economically efficient production systems are conceivable, differing in output mix, forms of social organization and community participation, size of operation, complexity of design and technical sophistication. Ideally, they should have a modular structure, allowing progressive implementation by adding new modules to the initial structure. While, in practice, these systems are often implemented as private enterprises, they can provide a template for the design and adoption of IFES technology at the community level in other circumstances, with appropriate modification, to mitigate environmental impacts and supply other benefits, towards improving the sustainability of food and energy production systems.

Related Posts:

http://tropicalenv.conforums.com/index.cgi?board=energy03&action=display&num=1217141112

http://www.sustainabilityforum.com/forum/sustainable-energy/2034-integrated-food-energy-systems-ifes.html

http://213.238.59.20/app/forum?op=showarticles;id=8635448;articleid=8635448

http://www.theenvironmentsite.org/forum/biofuel-forum/11964-integrated-food-energy-systems-ifes.html

http://discuss.greenoptions.com/viewtopic.php?f=40&t=500

http://www.unu.edu/unupress/unupbooks/80757e/80757E03.htm

“Spatial Footprint” Challenges of Solar Energy Use

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Submitted by: Karl Ramjohn

Solar energy can be utilized in either passive or active systems. Passive systems do not contain any internal energy sources, and can be used for direct heating (e.g. solar dryers, water heaters, etc.) or day-time lighting (e.g. “green” office buildings). Photovoltaic devices are an example of active systems based on semiconductor technology, often using silicon (an indirect semiconductor).

The advantages of using solar radiation are well established and often cited – such as their ability (with proper design) to lower energy costs, reduce emissions and other environmental pollution, thereby initiating the process of competitively replacing hydrocarbon use, and thus contributing to sustainable development.

Solar energy approaches are also frequently suggested as a sustainable solution in less-developed countries in the tropical environment, on the assumption of having less seasonal variation in day-length and more hours of direct sunlight each day (i.e., usually a higher intensity and longer duration of incident solar radiation each day). The fuel medium (solar radiation) is also an “open-access” resource (no direct user cost). The overall decline in the operational costs seen over the past 35+ years is also typically acknowledged.

However, one major challenge remains with regard to conversion to solar energy use – their spatial footprint (land use requirement) in the event that larger scale utilization is proven feasible. In particular, for the use of flat-plate collectors or PV systems in tropical environments, this becomes an issue.

The primary reason is that to optimize the use of solar radiation, the panels (or plates) need to be sloped so as to correspond to the latitude of the specific area of the Earth, hence taking up more horizontal space in the tropics. If we take the example of an island in the middle-tropics such Trinidad & Tobago, implementation will require the slope of the panels to be 10 degrees (corresponding to latitude) for the same technology that may be placed at an angle of 40 degrees in countries within temperate regions. The implication is that the area set aside for power generation (or other solar energy use) will no longer be available for other land uses (such as agriculture) and this may be a significant limiting factor, especially in the case of small-island developing states. After all, any large-scale conversion will require much more than a rooftop, and island geography often restricts the feasibility of wind energy.

Some recent discussions aimed at solving or mitigating these potential challenges to sustainable energy:

http://cr4.globalspec.com/thread/20329

https://www.xing.com/app/forum?op=showarticles;id=8635831

http://www.sustainabilityforum.com/forum/sustainable-energy/2032-spatial-footprint-challenges-solar-energy-use.html

Non-Turbine Wind Generator

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From: Green Tech Gazette – June 23, 2008

An interesting article (with video) on a non-traditional form of Wind Energy: Non-Turbine Wind Generator | Green Tech Gazette

According to that article, instead of generating electricity using a turbine based on the traditional two- or three-blade design, the non-turbine wind generator is based upon the flutter of long strands of kite material spanning a gap and connected to button magnets on the ends that produce electrical current. The design was conceived to provide an inexpensive solution to micro-wind energy, but has the option to be scaled up to meet larger power generation needs.

 

 

Written by geoenergy

July 5, 2008 at 3:25 pm

Some perspectives on the science of climate change

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By: Karl Ramjohn – June 2008

“Climate” is distinguished from “weather”, in that weather is the day-to-day state of the atmosphere and environment, whereas climate is the statistical average of weather patterns over a limited region and a long period (usually, minimum 30 years). A number factors have some influence on variations in the climate in the various regions or zones of the Earth – but it must be noted that none of these changes work (or actually initiate themselves) in isolation.

The natural climatic systems of the Earth are primarily determined by a dynamic complex of linkages, synergies and interactions among the processes, components and sub-systems of the atmosphere, hydrosphere, lithosphere and biosphere. The hydrosphere in this context includes all of the Earth’s water – oceans, rivers, lakes and the cryosphere (ice caps and snow). The main variables which characterize climate are temperature and precipitation (rainfall), humidity and cloudiness (special disturbances such as droughts and hurricances are sometimes included). These elements are in turn dependent on the meteorological variables (of weather) – such as insolation (solar radiation), wind speed and direction, ocean surface temperature, etc. To this must be added the variability of the Sun’s radiation and the Earth’s orbit, which result in an extremely complex and dynamic system.

Thus the climate system is a global complex of linkages and interactions. Inhomogeneities of all scales exist from the very large scale (e.g., 10,000 km) to the very small scale (e.g., 1 mm). This complex system is acted upon by a range of stimuli associated with the Sun, the Moon, and the Earth’s orbit around the sun. The main factors affecting climate change (natural variability) include: (1) Diurnal oscillations, due to the Earth’s rotation; (2) Tidal oscillations, due to gravitational effects of the Sun and Moon, with main periods of 12.4 hr and 24.8 hr; (3) Seasonal oscillations, due to the inclination of the equator to the ecliptic, and to changes in Sun-Earth distance; (4) Synoptic oscillations, caused by Rossby waves, with scales of 1000 km and periods of days; (5) Global oscillations with periods from weeks to months; (6) Inter-annual oscillations with periods ranging from 2 to 5 years, including El Niño/La Niña phenomena in the Pacific; and (7) Secular or long period oscillations with periods ranging from years to tens of thousands of years (the ice ages), likely due to orbital variations.

Having established the above – one of the main issues in the current debate is the possible effects of human industrial and other activities on the global climate. Despite the assertions in some quarters, anthropogenic effects are for the moment much less significant than these natural effects, the main concern being time-scales – their effects are felt within lifetimes rather than thousands of years. The critical point, is that many of the factors (“forcers” and “reactors”) in our current environment never existed in the past – many of the culprits (such as CFC) do not occur freely in nature, further to which, the rate of change of the release of naturally occurring greenhouse gases (such as carbon dioxide) over the past 200 yr or so (since the “industrial revolution”) is unprecedented and likely a result of human activities (such as deforestation). While, it is very true that global warming and climate change are a natural process on the Earth; the main issue is that the new or additional parameters added by human activities make it very difficult to use past cycles of “Ice Ages” and “Tropical Ages” to predict what is to be expected. Even if our activities are less significant than natural variations (in the global context), they definitely are not helping the situation. Environmental changes by human activities also affect the micro-climate in which we live, on an obviously much shorter time-scale.

Recent discussions related to this post:

http://www.geo-earth.com/forums/index.php?showtopic=7453

http://discuss.greenoptions.com/viewtopic.php?f=31&t=531

http://www.its2hot.in/viewtopic.php?f=27&t=96

http://debateclimatechange.talk-forums.com/science-of-climate-change-f1/some-perspectives-on-the-science-of-climate-change-t14.htm

http://www.physicsforums.com/showthread.php?t=236709

 

Written by geoenergy

July 5, 2008 at 2:38 pm