Showing papers on "Energy source published in 2001"

Wind Energy Handbook

Abstract: As environmental concerns have focused attention on the generation of electricity from clean and renewable sources wind energy has become the world's fastest growing energy source. The Wind Energy Handbook draws on the authors' collective industrial and academic experience to highlight the interdisciplinary nature of wind energy research and provide a comprehensive treatment of wind energy for electricity generation. Features include: * An authoritative overview of wind turbine technology and wind farm design and development * In-depth examination of the aerodynamics and performance of land-based horizontal axis wind turbines * A survey of alternative machine architectures and an introduction to the design of the key components * Description of the wind resource in terms of wind speed frequency distribution and the structure of turbulence * Coverage of site wind speed prediction techniques * Discussions of wind farm siting constraints and the assessment of environmental impact * The integration of wind farms into the electrical power system, including power quality and system stability * Functions of wind turbine controllers and design and analysis techniques With coverage ranging from practical concerns about component design to the economic importance of sustainable power sources, the Wind Energy Handbook will be an asset to engineers, turbine designers, wind energy consultants and graduate engineering students.

Ammonia-Oxidizing Bacteria: A Model for Molecular Microbial Ecology

Abstract: ▪ Abstract The eutrophication of many ecosystems in recent decades has led to an increased interest in the ecology of nitrogen transformation. Chemolitho-autotrophic ammonia-oxidizing bacteria are responsible for the rate-limiting step of nitrification in a wide variety of environments, making them important in the global cycling of nitrogen. These organisms are unique in their ability to use the conversion of ammonia to nitrite as their sole energy source. Because of the importance of this functional group of bacteria, understanding of their ecology and physiology has become a subject of intense research over recent years. The monophyletic nature of these bacteria in terrestrial environments has facilitated molecular biological approaches in studying their ecology, and progress in this field has been rapid. The ammonia-oxidizing bacteria of the β-subclass Proteobacteria have become somewhat of a model system within molecular microbial ecology, and this chapter reviews recent progress in our knowledge of ...

Fuel ethanol production from lignocellulose: a challenge for metabolic engineering and process integration.

Abstract: With industrial development growing rapidly, there is a need for environmentally sustainable energy sources. Bioethanol (ethanol from biomass) is an attractive, sustainable energy source to fuel transportation. Based on the premise that fuel bioethanol can contribute to a cleaner environment and with the implementation of environmental protection laws in many countries, demand for this fuel is increasing. Efficient ethanol production processes and cheap substrates are needed. Current ethanol production processes using crops such as sugar cane and corn are well-established; however, utilization of a cheaper substrate such as lignocellulose could make bioethanol more competitive with fossil fuel. The processing and utilization of this substrate is complex, differing in many aspects from crop-based ethanol production. One important requirement is an efficient microorganism able to ferment a variety of sugars (pentoses, and hexoses) as well as to tolerate stress conditions. Through metabolic engineering, bacterial and yeast strains have been constructed which feature traits that are advantageous for ethanol production using lignocellulose sugars. After several rounds of modification/evaluation/modification, three main microbial platforms, Saccharomyces cerevisiae, Zymomonas mobilis, and Escherichia coli, have emerged and they have performed well in pilot studies. While there are ongoing efforts to further enhance their properties, improvement of the fermentation process is just one of several factors-that needs to be fully optimized and integrated to generate a competitive lignocellulose ethanol plant.

Surgical system for applying ultrasonic energy to tissue

Abstract: A surgical system for controlled application of ultrasound energy to engaged tissue volumes for creating effective biological welds or seals in tissue. The invention provides an ultrasound transmission assembly including piezoelectric elements coupled to an elongate waveguide that is reciprocatable in an interior of an introducer. The reciprocatable waveguide assembly of the invention is adapted to have multiple functionality: (i) to couple ultrasound energy to both opposing jaws to thereby deliver energy to both sides of engaged tissues to create uniform thermal weld effects; (ii) to apply very high compressive forces to captured tissues over the length of elongate jaws by engaging substantially the entire length of the jaws, and (iii) to transect the captured tissues contemporaneous with the delivery of energy to create the thermal weld. The invention further provides for use of other energy sources to deliver thermal energy to tissue, for example microwave energy, Rf energy and laser energy, either in combination with ultrasound energy or independently.

Energy storage systems for advanced power applications

Abstract: While energy storage technologies do not represent energy sources, they provide valuable added benefits to improve stability power quality, and reliability of supply. Battery technologies have improved significantly in order to meet the challenges of practical electric vehicles and utility applications. Flywheel technologies are now used in advanced nonpolluting uninterruptible power supplies. Advanced capacitors are being considered as energy storage for power quality applications. Superconducting energy storage systems are still in their prototype stages but receiving attention for utility applications. The latest technology developments, some performance analysis, and cost considerations are addressed. This paper concentrates on the performance benefits of adding energy storage to power electronic compensators for utility applications.

Hydrogen Production. Green Algae as a Source of Energy

Abstract: Hydrogen gas is thought to be the ideal fuel for a world in which air pollution has been alleviated, global warming has been arrested, and the environment has been protected in an economically sustainable manner. Hydrogen and electricity could team to provide attractive options in transportation and power generation. Interconversion between these two forms of energy suggests on-site utilization of hydrogen to generate electricity, with the electrical power grid serving in energy transportation, distribution utilization, and hydrogen regeneration as needed. A challenging problem in establishing H2 as a source of energy for the future is the renewable and environmentally friendly generation of large quantities of H2 gas. Thus, processes that are presently conceptual in nature, or at a developmental stage in the laboratory, need to be encouraged,

Recent developments in lithium ion batteries

Abstract: Lithium ion rechargeable batteries are used as the power supply of cellular phones and several other portable electrical devices at present, and demand appears to increase exponentially. The concern about energy sources in the near future, either for electric vehicles (EV) or for large-scale batteries for electricity power storage, has made lithium ion rechargeable battery development into a growth area which has gained high momentum for its research activities. Here, while presenting the state of the art of lithium ion battery technology, the current research into materials, which constitute anode, electrolyte and cathode is described and the underlying problems associated with their development, advantages and drawbacks is analyzed. Both polymer electrolytes, which is a recent topic, as well as conventional organic liquids electrolyte, are also described.

Soyfood Intake during Adolescence and Subsequent Risk of Breast Cancer among Chinese Women

Abstract: Many experimental but few epidemiological studies have suggested that soyfoods and their constituents have cancer-inhibitory effects on breast cancer. No epidemiological study has evaluated the association of adolescent soyfood intake with the risk of breast cancer. To evaluate the effect of soyfood intake during adolescence, one of the periods that breast tissue is most sensitive to environmental stimuli, on subsequent risk of breast cancer, we analyzed data from a population-based case-control of 1459 breast cancer cases and 1556 age-matched controls (respective response rates were 91.1% and 90.3%). Information on dietary intake from ages 13-15 years was obtained by interview from all study participants and, in addition, from mothers of subjects less than 45 years of age (296 cases and 359 controls). Odds ratios (ORs) and 95% confidence intervals (CIs) derived from unconditional logistic models were used to measure soyfood intake and breast cancer risk. After adjustment for a variety of other risk factors, adolescent soyfood intake was inversely associated with risk, with ORs of 1.0 (reference), 0.75 (95% CI, 0.60-0.93), 0.69 (95% CI, 0.55-0.87), 0.69 (95% CI, 0.55-0.86), and 0.51 (95% CI, 0.40-0.65), respectively, for the lowest to highest quintiles of total soyfood intake (trend test, P < 0.001). The inverse association was observed for each of the soyfoods examined and existed for both pre- and postmenopausal women. Adolescent soyfood intakes reported by participants' mothers were also inversely associated with breast cancer risk (P for trend < 0.001), with an OR of 0.35 (95% CI, 0.21-0.60) for women in the highest soyfood intake group. Adjustment for rice and wheat products, the major energy source in the study population, and usual adult soyfood intake did not change the soyfood associations. Our study suggests that high soy intake during adolescence may reduce the risk of breast cancer in later life.

Geothermal energy for the benefit of the people

Abstract: Geothermal energy for electricity generation has been produced commercially since 1913, and for four decades on the scale of hundreds of MW both for electricity generation and direct use. The utilization has increased rapidly during the last three decades. In 2000, geothermal resources have been identified in over 80 countries and there are quantified records of geothermal utilization in 58 countries in the world. The worldwide use of geothermal energy amounts to 49 TWh/a of electricity and 53 TWh/a for direct use. Electricity is produced with geothermal steam in 21 countries spread over all continents. Five countries obtain 10–22% of their electricity from geothermal energy. Only a small fraction of the geothermal potential has been developed so far, and there is ample space for an accelerated use of geothermal energy both for electricity generation and direct applications. A comparison of the renewable energy sources (data from the UN World Energy Assessment Report) shows the current electrical energy cost to be 2–10 US¢/kWh for geothermal and hydro, 5–13 US¢/kWh for wind, 5–15 US¢/kWh for biomass, 25–125 US¢/kWh for solar photovoltaic and 12–18 US¢/kWh for solar thermal electricity. Of the total electricity production from renewables of 2826 TWh in 1998, 92% came from hydropower, 5.5% from biomass, 1.6% from geothermal and 0.6% from wind. Solar electricity contributed 0.05% and tidal 0.02%. Comparing four “new” renewable energy sources (geothermal, wind, solar and tidal), shows 70% of the electricity generated by the four to come from geothermal with only 42% of the total installed capacity. Wind energy contributes 27% of the electricity, but has 52% of the installed capacity. Solar energy produces 2% of the electricity and tidal energy 1%. Biomass constitutes 93% of the total direct heat production from renewables, geothermal 5%, and solar heating 2%. Heat production from renewables is commercially competitive with conventional energy sources. The current cost of direct heat from biomass is 1–5 US¢/kWh, geothermal 0.5–5 US¢/kWh, and solar heating 3–20 US¢/kWh. Geothermal energy, with its proven technology and abundant resources, can make a significant contribution towards reducing the emission of greenhouse gases.

Modern Electric Vehicle Technology

Abstract: 1. Engineering Philosophy of EV Developments 2. EV and HEV Developments 3. EV Systems 4. HEV Systems 5. Electric Propulsion 6. Energy Sources 7. EV Auxiliaries 8. EV Simulation 9. EV Infrastructure 10. Energy, environment and economy

Implications for energy flow in lotic food webs

Abstract: Stable-isotope ratios of carbon (13C/12C or 813C) have been widely used to determine the energy base of stream food webs, but such use is controversial due to un- explained variability in algal 813C. I used published 813C data from temperate headwater streams through medium-sized rivers (0.2-4000 km2 watershed area) collected during sum- mer baseflows and original data from streams in northern California to analyze energy pathways through river food webs. The analyses showed three important results. First, epilithic algal 813C and watershed area are positively related, suggesting that effects of carbon limitation on algal carbon uptake result in 13C enrichment of algal 813C in larger; more productive rivers. Second, epilithic algae and terrestrial detritus 813C values are often distinct in small shaded streams but overlap in some larger unshaded streams and rivers. Measurements of 813C values may be most useful in distinguishing algal and terrestrial energy sources in unproductive streams with supersaturated dissolved CO2 concentrations, and some productive rivers where CO2 concentrations are low relative to photosynthetic rates. Finally, consumer 813C values are more strongly related to algal 813C than terrestrial 813C. The relative contribution of terrestrial and algal carbon sources often varied by func- tional feeding group within and between sites. However, with the exception of shredders and scrapers, which respectively relied on terrestrial and algal carbon sources, patterns of consumer 813C clearly show a transition from terrestrial to algal carbon sources for many lotic food webs in streams with ?10 km2 watershed area. The observed transition to algal carbon sources is likely related to increasing primary production rates as forest canopy cover declines in larger streams, although decreasing retention or quality of terrestrial carbon may also play a role. Improved analyses of algal 813C and 815N combined with quantitative study of organic matter dynamics and food web structure should allow the relative im- portance of these factors to be distinguished in future food web studies.

Stable-carbon-isotope ratios of river biota:implications for energy flow in lotic food webs

Abstract: Stable-isotope ratios of carbon ( 13 C/ 12 Co rd 13 C) have been widely used to determine the energy base of stream food webs, but such use is controversial due to un- explained variability in algal d 13 C. I used published d 13 C data from temperate headwater streams through medium-sized rivers (0.2-4000 km 2 watershed area) collected during sum- mer baseflows and original data from streams in northern California to analyze energy pathways through river food webs. The analyses showed three important results. First, epilithic algal d 13 C and watershed area are positively related, suggesting that effects of carbon limitation on algal carbon uptake result in 13 C enrichment of algal d 13 C in larger, more productive rivers. Second, epilithic algae and terrestrial detritus d 13 C values are often distinct in small shaded streams but overlap in some larger unshaded streams and rivers. Measurements of d 13 C values may be most useful in distinguishing algal and terrestrial energy sources in unproductive streams with supersaturated dissolved CO2 concentrations, and some productive rivers where CO2 concentrations are low relative to photosynthetic rates. Finally, consumer d 13 C values are more strongly related to algal d 13 C than terrestrial d 13 C. The relative contribution of terrestrial and algal carbon sources often varied by func- tional feeding group within and between sites. However, with the exception of shredders and scrapers, which respectively relied on terrestrial and algal carbon sources, patterns of consumer d 13 C clearly show a transition from terrestrial to algal carbon sources for many lotic food webs in streams with $10 km 2 watershed area. The observed transition to algal carbon sources is likely related to increasing primary production rates as forest canopy cover declines in larger streams, although decreasing retention or quality of terrestrial carbon may also play a role. Improved analyses of algal d 13 C and d 15 N combined with quantitative study of organic matter dynamics and food web structure should allow the relative im- portance of these factors to be distinguished in future food web studies.

Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth

Abstract: The much-studied Murchison meteorite is generally used as the standard reference for organic compounds in extraterrestrial material. Amino acids and other organic compounds important in contemporary biochemistry are thought to have been delivered to the early Earth by asteroids and comets, where they may have played a role in the origin of life. Polyhydroxylated compounds (polyols) such as sugars, sugar alcohols and sugar acids are vital to all known lifeforms-they are components of nucleic acids (RNA, DNA), cell membranes and also act as energy sources. But there has hitherto been no conclusive evidence for the existence of polyols in meteorites, leaving a gap in our understanding of the origins of biologically important organic compounds on Earth. Here we report that a variety of polyols are present in, and indigenous to, the Murchison and Murray meteorites in amounts comparable to amino acids. Analyses of water extracts indicate that extraterrestrial processes including photolysis and formaldehyde chemistry could account for the observed compounds. We conclude from this that polyols were present on the early Earth and therefore at least available for incorporation into the first forms of life.

Ammonia toxicity, tolerance, and excretion

Abstract: Ammonia is an unusual toxicant in that it is produced by, as well as being poisonous to, animals. In aqueous solution ammonia has two species, NH3 and NH4+, total ammonia is the sum of [NH3] + [NH4+] and the pK of this ammonia/ammonium ion reaction is around 9.5. The NH3/NH4+ equilibrium both internally in animals and in ambient water depends on temperature, pressure, ionic strength, and pH; pH is most often of greatest significance to animals. Elevated ammonia levels in the environment are toxic. Temperature has only minor effects on ammonia toxicity expressed as total ammonia in water, and ionic strength of the water can influence ammonia toxicity, but pH has a very marked effect on toxicity. Acid waters ameliorate, whereas alkaline waters exacerbate ammonia toxicity. The threshold concentration of total ammonia ([NH3] + [NH4+]) resulting in unacceptable biological effects in freshwater, promulgated by the EPA (1998), is 3.48 mg N/liter at pH 6.5 and 0.25 mg N/liter at pH 9.0. There is only a relatively small saltwater data set, and a paucity of data on ammonia toxicity in marine environments, particularly chronic toxicity. The national criteria promulgated in the EPA (1989) saltwater document is a criterion continuous concentration (chronic value) of 0.99 mg N/liter total ammonia and a criterion maximum concentration (half the mean acute value) of 6.58 mg N/liter total ammonia, somewhat less than the equivalent freshwater pH 8.0 values of 1.27 and 8.4 mg N/liter total ammonia, respectively. This is consistent with marine species being somewhat more sensitive to ammonia than freshwater species. Toxicity studies are usually carried out on unfed, resting fish in order to facilitate comparison of results. Based on recent studies, however, environmental stresses, including swimming, can have dramatic effects on ammonia toxicity. It is also clear that feeding results in elevated postprandial body ammonia levels. Thus, feeding will probably also exacerbate ammonia toxicity. Fish may be more susceptible to elevated ammonia levels during and following feeding or when swimming. Thus, present ammonia criteria may fail to protect migrating fish and may be inappropriate for fish fed on a regular basis. Most teleost fish are ammonotelic, producing and excreting ammonia by diffusion of NH3 across the gills. They are very susceptible to elevated tissue ammonia levels under adverse conditions. Some fish avoid ammonia toxicity by utilizing several physiologic mechanisms. Suppression of proteolysis and/or amino acid catabolism may be a general mechanism adopted by some fishes during aerial exposure or ammonia loading. Others, like the mudskipper, can undergo partial amino acid catabolism and use amino acids as an energy source, leading to the accumulation of alanine, while active on land. Some fish convert excess ammonia to less toxic compounds including glutamine and other amino acids for storage. A few species have active ornithine—urea cycles and convert ammonia to urea for both storage and excretion. Under conditions of elevated ambient ammonia, the mudskipper P. schlosseri can continue to excrete ammonia by active transport of ammonium ions. There are indications that some fish may be able to manipulate the pH of the body surface to facilitate NH3 volatilization during aerial exposure, or that of the external medium to lower the toxicity of ammonia during ammonia loading. Future investigation of these aspects of “environmental ammonia detoxification” may produce new information on how fish avoid ammonia intoxication.

Ablation catheter assembly with radially decreasing helix and method of use

Abstract: A catheter assembly for treatment of cardiac arrhythmia. The catheter assembly includes a catheter body and an ablative energy source. The catheter body includes a proximal portion, an intermediate portion, and a distal portion. The intermediate portion extends from the proximal portion and defines a longitudinal axis. The distal portion extends from the intermediate portion and includes an ablation section and a tip. The ablation section forms a loop defining a diameter greater than an outer dimension of a pulmonary vein ostium. The tip extends distally from the ablation section and is configured to locate a pulmonary vein. Finally, the ablative energy source is associated with the ablation section. With this configuration, upon activation of the energy source, the ablation section ablates a desired lesion pattern. In one preferred embodiment, the ablation section forms a distally decreasing radius helix, whereas the tip includes a relatively linear leader section. With this one preferred configuration, the tip readily locates a pulmonary vein and guides the ablation section to a seated relationship about a pulmonary vein ostium (or extra-ostial).

Biomass conversion to carbon adsorbents and gas

Abstract: A process is created for the utilization of biomass by producing carbon adsorbents and gas. Carbon adsorbents with alkaline character of the surface, tar and gas products are obtained by steam pyrolysis of biomass (almond shells, nut shells, apricot stones, cherry stones, grape seeds). Mixtures of tar obtained during this process and furfural are used for obtaining carbon adsorbents with low ash and sulphur contents and different chemical character of the surface. The chemical character of oxygen functional groups on their surface reveals that they are polyfunctional cationites. Carbon adsorbents obtained have a hydrophilic surface and are suitable for removing metal ions and other pollutants from water. The gas products can be used as energy source.

Glucose and lactate metabolism during brain activation.

Abstract: The dependence of brain function on blood glucose as a fuel does not exclude the possibility that lactate within the brain might be transferred between different cell types and serve as an energy source. It has been recently suggested that 1) about 85% of glucose consumption during brain activation is initiated by aerobic glycolysis in astrocytes, triggered by demand for glycolytically derived energy for Na+ -dependent accumulation of transmitter glutamate and its amidation to glutamine, and 2) the generated lactate is quantitatively transferred to neurons for oxidative degradation. However, astrocytic glutamate uptake can be fueled by either glycolytically or oxidatively derived energy, and the extent to which "metabolic trafficking" of lactate might occur during brain function is unknown. In this review, the potential for an astrocytic-neuronal lactate flux has been estimated by comparing rates of glucose utilization in brain and in cultured neurons and astrocytes with those for lactate release and uptake. Working brain tissue and isolated brain cells release large amounts of lactate. Cellular lactate uptake occurs by carrier-mediated facilitated diffusion and is normally limited by its dependence on metabolism of accumulated lactate to maintain a concentration gradient. The rate of this process is similar in cultured astrocytes and glutamatergic neurons, and, at physiologically occurring lactate concentrations, lactate uptake corresponds at most to 25% of the rate of glucose oxidation, which accordingly is the upper limit for "metabolic trafficking" of lactate. Because of a larger local release than uptake of lactate and the necessity for rapid lactate clearance to maintain the intracellular redox state to support lactate production in the presence of normal oxygen levels, brain activation in vivo is probably, in many cases, accompanied by a substantial overflow of glycolytically generated lactate, both to different brain areas and under some conditions (spreading depression, hyperammonemia) to circulating blood.

Ten residual biomass fuels for circulating fluidized-bed gasification

Abstract: In co-operation with a Dutch company (NV Afvalzorg) and the Dutch agency for energy and environment (Novem), ECN has successfully tested 10 different biomass residues in its 500 kW th circulating fluidized-bed gasification facility. Among the fuels used are demolition wood (both pure and mixed with sewage sludge and paper sludge), verge grass, railroad ties, cacao shells and different woody fuels. Railroad ties turn out to contain very little (heavy) metals. Initially, fuel feeding problems often impeded smooth operation. Contrary to feeding systems, the circulating fluidized-bed gasification process itself seems very flexible concerning the conversion of different kinds of biomass fuels. The fuel moisture content is one of the most important fuel characteristics. More moisture means that more air is needed to maintain the process temperature resulting in better carbon conversion and lower tar emission but also lower product gas heating value and lower cold gas efficiency. So, for a good comparison of the gasification behaviour of different fuels, the moisture content should be similar. However, the moisture content should be defined on an ash-free basis rather than on total mass (the usual way). Some of the ashes produced and retained in the second cyclone were analysed both for elemental composition and leaching behaviour. It turned out that the leaching rate of Mo and Br, elements only present in small concentrations, are preventing the ash to be considered as inert material according to the Dutch legislation for dumping on landfill sites.

Adenosine 5′-Triphosphate: a P2-Purinergic Agonist in the Myocardium

Abstract: ATP, besides an intracellular energy source, is an agonist when applied to a variety of different cells including cardiomyocytes. Sources of ATP in the extracellular milieu are multiple. Extracellu...

Optimizations for live event, real-time, 3d object tracking

Abstract: Various combinations of camera assembly (500), tracking frequency (510), energy source (520), marker; emission method (530), marker; physical form (540), marker; reflective shape (550), ID: location (560), ID: encoding method (570), ID: obtained (580) and calibration method (590) forming a preferred embodiment (1004) as well as several alternative embodiments for tracking the movement of multiple objects within a predetermined area. Camera assembly (500) optionally comprises fixed volume tracking (502), fixed area tracking (504) and movable volume tracking (506). Tracking frequency (510) optionally comprises visible light (512), infrared light (514) and ultraviolet light (516).

Reliability/Cost Implications of PV and Wind Energy Utilization in Small Isolated Power Systems

Abstract: The application of renewable energy in electric power systems is growing rapidly due to enhanced public concerns for adverse environmental impacts and escalation in energy costs associated with the use of conventional energy sources. Photovoltaics and wind energy sources are being increasingly recognized as cost-effective generation sources in small isolated power systems primarily supplied by costly diesel fuel. The utilization of these energy sources can significantly reduce the system fuel costs but can also have considerable impact on the system reliability. A realistic cost/reliability analysis requires evaluation models that can recognize the highly erratic nature of these energy sources while maintaining the chronology and interdependence of the random variables inherent in them. This paper presents a simulation method that provides objective indicators to help system planners decide on appropriate installation sites, operating policies, and selection of energy types, sizes, and mixes in capacity expansion when utilizing PV and wind energy in small isolated systems.

The Subterranean Forest: Energy Systems and the Industrial Revolution

Abstract: The Subterrranean Forest studies the historical transition from the agrarian solar-energy regime to the use of fossil energy, which has fuelled the industrial transformation of the last 200 years. The author argues that the analysis of historical energy systems provides an explanation for the basic patterns of different social formations. It is the availability of free energy that defines the framework within which socio-metabolic processes can take place. This thesis explains why the industrial revolution started in Britain, where coal was readily available and firewood already depleted or difficult to transport, whereas Germany, with its huge forests next to rivers, came much later. This landmark text was originally published in German in 1982 and was thoroughly revised and updated for the White Horse Press in 2001.

A Prosperous Way Down: Principles And Policies

Abstract: Consider the future with less fossil fuel and no new natural or technological energy sources. How can it be peaceful and prosperous? More and more leaders concerned with the global future are warning of the impending crisis as the surge of unsustainable growth exceeds the capability of the earth's resources to support our civilisation. But while history records the collapse of countless civilisations, some societies and ecosystems have managed to descend in orderly stages, reducing demands and selecting and saving what is most important. Although some scientists predict disaster, this book shows how our world can still thrive and prosper in a future where we live with less and charts a way for our modern civilisation to descend to sustainable levels. The authors make recommendations for a more equitable and co-operative world society, with specific suggestions based upon their evaluations of trends in global population, wealth distribution, energy sources, conservation, urban development, capitalism and international trade, information technology, and education. This thoughtful and provocative book will force us to confront our assumptions and beliefs about our world's future, which is all too often taken for granted.<