3,317,656 research outputs found

    Commercial energy efficiency and the environment

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    The production and use of energy create serious, extensive environmental affects at every level, in every country, argue the authors. That impact may be more serious in developing than in developed countries as developing countries depend more on natural resources and lack the economic strength to withstand environmental consequences. At the same time, a reliable energy supply is vital to economic growth and development. Energy consumption and economic growth have been somewhat delinked at high income levels, but increased energy consumption (especially of electricity) is inevitable with higher GDP. Greater energy efficiency in developing countries and Eastern Europe is a high-priority way to mitigate the harm to the environment of growing energy consumption, say the authors. They outline four advantages of greater energy efficiency. It requires measures that are in the economic self-interest of those regions. Political obstacles make these measures difficult, but there are well-established techniques for addressing concerns about low-income consumers (such as direct income support or life-line rates). It will help conserve the world supply of nonrenewable (especially fossil) fuels. It will encourage appropriate fuel switching. It addresses every level of concern, up to the global effects of global warming. Any strategy to make energy use and production more efficient must rely more extensively than before on markets that are allowed to function with less government interference. The crucial components of such a straetegy (also crucial to economic development generally) are: more domestic and external competition; the gradual elimination of energy pricing distortions; the reduction of macroeconomic and sectoral distortions (for example, in foreign exchange and credit markets); the reform of energy supply enterprises - reducing state interference, providing more financial autonomy and a greater role for the private sector; consumer incentives to select more efficient lights, space heating, and so on. The authors are not convinced of the need for nonmarket approaches beyond those geared to correct externalities, provide essential information, support basic research and development, and possibly promote pilot projects. They also conclude that a government is far more likely to take action to reduce an environmental externality if it captures benefits within its own national boundaries that exceed the cost of the action. Reducing the large difference between energy prices and economic costs in developing countries and Eastern Europe is a more immediate issue than carbon taxes. The developed countries, say the authors, have an indispensable role to play in improving energy efficiency in the developing countries and Eastern Europe. They can encourage the flow of efficient technology, they can increase conventional aid, and they must accept a greater share of the burden of protecting the global commonalities.Energy and Environment,Environmental Economics&Policies,Energy Demand,Transport and Environment,Power&Energy Conversion

    Environment and Energy Injection Effects in GRB Afterglows

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    In a recent paper (Dai & Lu 1999), we have proposed a simple model in which the steepening in the light curve of the R-band afterglow of the gamma-ray burst (GRB) 990123 is caused by the adiabatic shock which has evolved from an ultrarelativistic phase to a nonrelativistic phase in a dense medium. We find that such a model is quite consistent with observations if the medium density is about 3×106cm33\times 10^6 {\rm cm}^{-3}. Here we discuss this model in more details. In particular, we investigate the effects of synchrotron self absorption and energy injection. A shock in a dense medium becomes nonrelativistic rapidly after a short relativistic phase. The afterglow from the shock at the nonrelativistic stage decays more rapidly than at the relativistic stage. Since some models for GRB energy sources predict that a strongly magnetic millisecond pulsar may be born during the formation of GRB, we discuss the effect of such a pulsar on the evolution of the nonrelativistic shock through magnetic dipole radiation. We find that after the energy which the shock obtains from the pulsar is much more than the initial energy of the shock, the afterglow decay will flatten significantly. When the pulsar energy input effect disappears, the decay will steepen again. These features are in excellent agreement with the afterglows of GRB 980519, GRB 990510 and GRB 980326. Furthermore, our model fits very well all the observational data of GRB 980519 including the last two detections.Comment: 21 pages, LaTeX, accepted for publication in ApJ, one paragraph adde

    Energy-water-environment nexus underpinning future desalination sustainability

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    Energy-water-environment nexus is very important to attain COP21 goal, maintaining environment temperature increase below 2 °C, but unfortunately two third share of CO2 emission has already been used and the remaining will be exhausted by 2050. A number of technological developments in power and desalination sectors improved their efficiencies to save energy and carbon emission but still they are operating at 35% and 10% of their thermodynamic limits. Research in desalination processes contributing to fuel World population for their improved living standard and to reduce specific energy consumption and to protect environment. Recently developed highly efficient nature-inspired membranes (aquaporin & graphene) and trend in thermally driven cycle's hybridization could potentially lower then energy requirement for water purification. This paper presents a state of art review on energy, water and environment interconnection and future energy efficient desalination possibilities to save energy and protect environment

    China’s New Development Strategy: Environment and Energy Security

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    This paper analyzes China's development strategy by focusing on both global and regional approaches to solving problems of energy security and ecological imbalance by addressing specifically the problems of China’s energy security. PRC’s growing energy dependence has become a major concern for both economic and national security policymakers in that country. The ambitious goal of modernization of the economy along the lines of the other newly industrialized economies(NIEs) of Asia has succeeded only too well, and it is difficult to reorient economic priorities. If examined rigorously, such an economic strategic assumption can be seen to entail the goal of creating further technological capabilities. In particular, China seems to be firmly committed to the creation of a largely self-sustaining innovation system as part of a knowledge-based economy of the future . Such innovation systems, called positive feedback loop innovation systems or POLIS have been created by advanced countries, and NIEs such as South Korea and Taiwan are proceeding to create these as well. But this will add to its energy burden and further dependence on the US as the power which controls the key sea lanes. Only a strategic reorientation to building a self-sustaining POLIS and appropriate regional cooperation institutions can lead to the way out of the current dilemma for China. Fortunately, such a model of POLIS which is distributionally and ecologically sensitive can be built for China and applied strategically to lead towards a sustainable development trajectory. However, time is of the essence. Given the path dependence of development unless strategic disengagement from the existing path followed by a strategic engagement with the alternative strategy is begun within the next five years, it may well be too late. The stakes are indeed very high. A more detailed strategy paper based on the key ideas from the alternative strategy outlined here with concrete quantitative scenarios and feasibility studies along the lines of models sketched in the appendix ( and other, more detailed models) will go some distance towards giving the appropriate analytical foundations for the policy makers. The preliminary results confirm the predictions regarding fossil fuel-based energy shortage and lead towards a serious consideration of alternative energy sources. Achieving the twin goals of energy security and ecological balance are challenging but not impossible for China. Serious policy research can be used effectively if there is the political will to do so. The goal of regional cooperation is also achievable if patient negotiations in good faith can start in earnest. In particular, cooperation with other Asian economies, particularly Japan, Indonesia, Viet Nam and India will be crucial.This paper has sketched out the complexities of cooperation and conflict between China and Japan. Future work will address the problems of Regional cooperation for China in the East, South and South Asian context as well as in the context of Africa and Latin America.China, Development Strategy, Energy, Environment, POLIS, Innovation System, Regional Cooperation

    Is it possible to formulate least action principle for dissipative systems?

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    A longstanding open question in classical mechanics is to formulate the least action principle for dissipative systems. In this work, we give a general formulation of this principle by considering a whole conservative system including the damped moving body and its environment receiving the dissipated energy. This composite system has the conservative Hamiltonian H=K1+V1+H2H=K_1+V_1+H_2 where K1K_1 is the kinetic energy of the moving body, V1V_1 its potential energy and H2H_2 the energy of the environment. The Lagrangian can be derived by using the usual Legendre transformation L=2K1+2K2HL=2K_1+2K_2-H where K2K_2 is the total kinetic energy of the environment. An equivalent expression of this Lagrangian is L=K1V1EdL=K_1-V_1-E_d where EdE_d is the energy dissipated by the friction from the moving body into the environment from the beginning of the motion. The usual variation calculus of least action leads to the correct equation of the damped motion. We also show that this general formulation is a natural consequence of the virtual work principle.Comment: 11 pages, no figur

    Low temperature transport in tunnel junction arrays: Cascade energy relaxation

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    A theory of far-from-equilibrium transport in arrays of tunnel junctions is developed. We show that at low temperatures the energy relaxation ensuring tunneling current can become a cascade two-stage process. First, charge carriers lose their energy to a bosonic environment via non-phonon energy exchange. The role of such an environment can be taken by electromagnetic fluctuations or dipole excitations (electron-hole pairs). The environment, in its turn, relaxes the energy to the thermostat by means of phonon irradiation. We derive the current-voltage characteristics for the arrays and demonstrate that opening the energy gap in the spectrum of the environmental excitations completely suppresses the tunneling current. The consequences of the cascade relaxation in various physical systems are discussed.Comment: 20 pages, 3 figure

    Trade-off analysis and design of a Hydraulic Energy Scavenger

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    In the last years there has been a growing interest in intelligent, autonomous devices for household applications. In the near future this technology will be part of our society; sensing and actuating will be integrated in the environment of our houses by means of energy scavengers and wireless microsystems. These systems will be capable of monitoring the environment, communicating with people and among each other, actuating and supplying themselves independently. This concept is now possible thanks to the low power consumption of electronic devices and accurate design of energy scavengers to harvest energy from the surrounding environment. In principle, an autonomous device comprises three main subsystems: an energy scavenger, an energy storage unit and an operational stage. The energy scavenger is capable of harvesting very small amounts of energy from the surroundings and converting it into electrical energy. This energy can be stored in a small storage unit like a small battery or capacitor, thus being available as a power supply. The operational stage can perform a variety of tasks depending on the application. Inside its application range, this kind of system presents several advantages with respect to regular devices using external energy supplies. They can be simpler to apply as no external connections are needed; they are environmentally friendly and might be economically advantageous in the long term. Furthermore, their autonomous nature permits the application in locations where the local energy grid is not present and allows them to be ‘hidden' in the environment, being independent from interaction with humans. In the present paper an energy-harvesting system used to supply a hydraulic control valve of a heating system for a typical residential application is studied. The system converts the kinetic energy from the water flow inside the pipes of the heating system to power the energy scavenger. The harvesting unit is composed of a hydraulic turbine that converts the kinetic energy of the water flow into rotational motion to drive a small electric generator. The design phases comprise a trade-off analysis to define the most suitable hydraulic turbine and electric generator for the energy scavenger, and an optimization of the components to satisfy the systems specification

    Bolivia: Energy and Environment

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    This unpublished encyclopedia entry gives an overview of Bolivia\u27s energy resources and mining, and describes the mining industry\u27s impact on the environment
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