Climate change and energy policy in Eastern Europe: Two scenarios for the future

The citizens of Poland, Eastern Germany, Czechoslovakia, Hungary, and Romania inhabit perhaps the most polluted environments in the world, largely because of their countries' inefficient use of energy. Energy use is two to three times greater per unit of economic output than in Western Europe. Energy inefficiency also constrains economic growth by diverting capital to unproductive use. As much as 40% of all industrial investment in Poland was consumed in energy production.The emerging democracies of Eastern Europe have embarked on reforms to make their economies more efficient. We assess their potential for energy efficiency and apply end-use analysis in an energy end-use economic model to evaluate future energy use in the region. We assume that Eastern Europe will approach current Western living standards over the next three decades and that this will in turn increase energy consumption. We have found, nevertheless, that Eastern European nations could hold energy demand virtually constant through structural reform and technical energy-efficiency improvement. The six countries in the region could save as much as 3.5 exajoules per year, with savings yielding an economic benefit of $300 million annually.Capturing the energy-efficiency potential in Eastern Europe would require a combination of market forces and policy initiatives. Such optimistic prediction, however, should not be taken at face value. Financial and technical constraints will impede some of the potential gains in energy efficiency in Eastern Europe. Overcoming them will require national leadership and decisive international cooperation.     

Dynamical energy limits in traditional and work-driven operations II.: Systems with heat and mass transfer

This is the second part of the work that analyses dynamical energy limits for diverse operations with finite rates important in engineering. Our position is that a dynamic limit of a sufficiently high hierarchy may be helpful in modelling and design of a prescribed operation. In particular, we treat active systems with coupled heat and mass transfer important in separation and biological systems. The operations considered occur in separation units, heat and mass exchangers, energy converters and chemical reactors. The energy limits are expressed in terms of classical exergy and a residual minimum of entropy generated in equipment of a fixed dimension. To ensure physical limits we treat sequential work-driven operations, in particular those of dissolving or evaporation which run jointly with thermal machines (e.g. heat pumps). We also compare structures of optimization criteria describing these limits (in particular “endoreversible limits”) in traditional and work-driven operations. Through quantitative analyses we extend to the realm of mass transfer operations the method initiated in Part I that applies “Carnot variables” as suitable controls. Functions of extremum work, which apply a residual minimum entropy production, are found in terms of initial and final states, duration and (in discrete processes) number of stages. Mathematical analogies between entropy production expressions in traditional and work-driven operations are helpful to formulate optimization criteria in both cases.     

Use of the higher spectra in the low-amplitude fatigue testing

Particular place among the methods of vibroacoustic diagnostics is occupied by the problems of early defect detection. Let us note that the process of defect formation may lead to both. The intensification of non-linear phenomena as well as the occurrence of non-stationary effects even if during the early stages the intensity of defects is small while the growth of the level of vibration and noise is negligible, as contrasted with emergency states. A useful method is to test the higher order spectra, which, respectively, define the non-linear effects. A test bed for low-amplitude tests (10⁶-10⁷ cycles) of fatigue processes was built. The authors built a small-dimension test bed for diagnosing the low-amplitude fatigue processes. Small dimensions result from the proposal of mounting the test bed on shaker. The dimensions of test bed are 0.2×0.2×0.2 m and its weight does not exceed 2 kg, with a titan head mounted directly on the piezoelectric generator. The main goal of these investigations is to examine the low-amplitude fatigue strength of a model of the cantilever supported section of a shaft and impact of dynamic stress, which is especially important in the case of high frequency loading which is predominant in mounting elements of rotating machinery.     

Characteristic time,developers’ behavior and leapfrogging dynamics of high-rise buildings

This paper suggests a plausible explanation for the spatial evolution of high-rise buildings. Contrary to intuitive expectations the histograms and spatial distribution in cities indicate peculiar and non-continuous patterns. These patterns evolve as a result of developers’ behavior in real-estate markets. One of the critical variables in decision-making of developers is time. Despite obvious differences in land prices within a particular real-estate market, differences in costs and prices are relatively small in comparison to differences in their time incidence. The paper presents a simple search model of land developer that suggests interesting explanation of the spatial sprawl of cities. The central parameter in our model is “characteristic time”, the period of time from the acquisition of initial property rights in the land and until the first return on the investment is realized. The model leads to leapfrogging patterns, particularly during downturn periods and explains the appearance of high-rise buildings in the urban periphery.