Effect of class-interval size on entropy

The value of Shannon entropy for a given set of data depends on the class interval chosen to compute the relative frequency of each class. For three data sets, expressed in dimensional as well as nondimensional form, the entropy value was computed for different class-interval sizes. Entropy was found to decrease with increasing class interval as well as with increasing sampling interval. It is suggested that these intervals should be selected with care.     

Comparison of Fiberglass and Other Polymeric Well Casings, Part I: Susceptibility to Degradation by Chemicals

Previous research has shown that the most commonly used well casing materials-stainless steel. polyvinyl chloride (PVC). and polytetra-fluoroethylene (PTFE)-are not suited for all monitoring environments and applications. This study is part of a series of experiments that were conducted to determine the suitability of four other polymeric well casing materials-acrylonitrile butadiene styrene (ABS), fluorinalcd ethylene propylene (FHP), fiberglass-reinlorced epoxy (FRE), and fiberglass-reinforced plastic (FRP)- for use in ground water monitoring wells. In these studies, these four materials were compared with two other commonly used polymeric well casings, PVC and PTFE. Part I of these studies examines the resistance of these materials to degradation by chemicals. Future reports will consider sorption and leaching of organic and metal contaminants.
In this study, the six materials were exposed to 28 neat organic compounds (including one acid) and to extremely acidic and alkaline aqueous solutions for up to 112 days. This was done to simulate the most aggressive environments to which monitoring well casings may be exposed. The casings were observed for changes in weight and signs of physical degradation (swelling, softening, deterioration, or dissolution).
The two fluorinated polymers (FEP and PTFE) were not degraded by any of the lest chemicals. Among the nonfluorinated products tested. FRE was the most inert. Three organic chemicals caused the glass fibers to separate. and two organic solvents caused weight gains exceeding 10 percent. ABS was the most readily degraded material tested. By the end of the study, only the acid and alkaline solutions had little effect on ABS. FRP was more severely degraded by the organic chemicals than FRH but was less affected than PVC. FRP and FRE. lost weight when exposed to the highly acidic conditions.     

Temporal behaviour of artificial small-scale ionospheric irregularities: Review of experimental results

Features of artificial small-scale ionospheric irregularities (ASI) induced at F-region heights by powerful HF waves are discussed. The investigations presented here were performed during the past two decades at the Zimenki and Sura heating facilities, located at middle latitudes near Nizhniy Novgorod, Russia, as well as at the Gissar facility located at a lower latitude near Dushanbe, Tadzhikistan. The measurements were made by a variety of diagnostic methods employing artificial field-aligned scattering of HF and VHF radio waves, sounding of the disturbed region by means of low-power probing waves and testing of the artificial turbulence by means of stimulated electromagnetic emission (SEE). The dependence of ASI on such parameters as transverse scale length of the artificial irregularities, their location in the disturbed region, the power of the heating wave, the duration of HF radiation, geophysical conditions, aftereffects of the preceding modification, and the schedule of heater operation is considered for both the development stage after pump turn-on and the decay stage after pump turn-off. The temporal evolution of ASI spectral characteristics during the heater period is discussed. An empirical model for the ASI, based on the data available, was elaborated and verified by computer simulation of SEE generation.     

Russia at GHG Market

In the first Kyoto commitment period Russia could be the major supplier for the greenhouse gases (GHG) emissions market. Potential Russian supply depends on the ability of Russia to keep GHG emissions lower than the Kyoto target. In the literature there is no common understanding of the total trading potential of Russia at the international carbon market. In this paper we focus on CO₂ emission, which constituted nearly 80%of Russian GHG emission. We compare different projections of Russian CO₂emission and analyze the most important factors, which predetermine the CO₂emission growth. In a transition economy these factors are: Gross Domestic Product(GDP) dynamic, changes of GDP structure, innovation activity, transformation of export-import flows and response to the market signals. The input-output macroeconomic model with the two different input-output tables representing old and new production technologies has been applied for the analysis to simulate technological innovations and structural changes in the Russian economy during transition period. The Russian supply at the international GHG market without forest sector may be up to 3 billion metric ton of CO₂ equivalent. Earlier actions to reduce CO₂ emission are critical to insure theRussiansupply at the international carbon market. With regard to the current status of the Russian capital market, the forward trading with OECD countries is only the possibility to raise initial investments to roll no-regret and low-cost GHG reduction. This paper discusses uncertainties of RussianCO₂emission dynamics and analyzes the different incentives to lower the emission pathway.     

多年冻土地区金刚石矿的环境问题--以Yakutia 西北部Anabar矿为例

Placer diamond mining in the Anabar area involves various operations that cause long-term (nearly a quarter of a century) environmental impacts. The long history of mining activities, the technology used to mine the placers, as well as the poor assimilative capacity of the natural systems can result in serious environmental impacts in the area. The primary geochemical processes in the diamond-bearing area are affected by the occurrence of permafrost and relict ice, the lengthy duration of ice cover in water bodies, and the widespread development of cryogenic processes. This promotes physical migration of contaminants, cryogenic metamorphization of waters, and long-term accumulation of organic contaminants in low-temperature, reduction and sedimentation barriers. In this paper, some environmental and geochemical effects of diamond mining in the Arctic area are discussed.     

Evolution of sand waves in the Messina Strait, Italy

In the present paper the morphodynamics of sand waves in the Messina Strait, Italy, is analysed by comparing data gathered during two different surveys carried out in 1991 and 2001, respectively. In particular, a morphometric analysis on the most recent data and a qualitative analysis of the differences between bottom bedform patterns, are carried out. At locations characterised by greater depths, only minor changes to the planimetric configuration of the field, i.e. crest orientation (which is seen to be orthogonal to the direction of net gross sand transport) and wave length are observed, while differences in wave length and crest direction are more evident in more shallow areas. On the other hand, wave height has significantly increased in the whole field. A possible explanation of such a change, based on the previsions of a theory which relates sand-wave growth and migration to the main components of the tidal ellipse, is provided.Responsible Editor: Jens Kappenberg     

Statistical Detection and Characterization of a Deviation from the Gutenberg-Richter Distribution above Magnitude 8

— We present a quantitative statistical test for the presence of a crossover c₀ in the Gutenberg-Richter distribution of earthquake seismic moments, separating the usual power-law regime for seismic moments less than c₀ from another faster decaying regime beyond c₀. Our method is based on the transformation of the ordered sample of seismic moments into a series with uniform distribution under condition of no crossover. A simulation method allows us to estimate the statistical significance of the null hypothesis H₀ of an absence of crossover (c₀=infinity). When H₀ is rejected, we estimate the crossover c₀ using two different competing models for the second regime beyond c₀ and the simulation method. For the catalog obtained by aggregating 14 subduction zones of the Circum-Pacific Seismic Belt, our estimate of the crossover point is log(c₀)=28.14 ± 0.40 (c₀ in dyne-cm), corresponding to a crossover magnitude m_W=8.1 ± 0.3. For separate subduction zones, the corresponding estimates are substantially more uncertain, so that the null hypothesis of an identical crossover for all subduction zones cannot be rejected. Such a large value of the crossover magnitude makes it difficult to associate it directly with a seismogenic thickness as proposed by many different authors. Our measure of c₀ may substantiate the concept that the localization of strong shear deformation could propagate significantly in the lower crust and upper mantle, thus increasing the effective size beyond which one should expect a change of regime.