Diagnostic analysis of offensive odorants in a large municipal waste treatment plant in an urban area

A diagnostic study was conducted to examine the effectiveness of malodor removal from a large-scale municipal waste treatment plant in an urban area. To this end, the odor pollution status was investigated from a total of 16 spots in the treatment facility to cover the dual treatment lines consisting of regenerative thermal oxidation (first stage) and a wet chemical scrubber (second stage). As a simple means to learn more about the odorant removal efficiency of different treatment units, samples collected from ambient spots as well as before and after each treatment unit were analyzed for 22 key offensive odorants (i.e., reduced sulfur compounds, carbonyl compounds, nitrogenous compounds, volatile organic compounds, and fatty acids) along with dilution-to-threshold ratios based on the air dilution sensory test. The removal patterns differed greatly between different odorant groups across different processing units. The effectiveness of this dual treatment system was optimized for such odorants as hydrogen sulfide and ammonia, while it was not the case for others (e.g., some aldehydes and organic acids). The results thus suggest the need for the validation of the efficiency in many types of odor processing units and for establishing new control techniques to cover a list of odorants un-subordinate to preexisting methods.     

From polygons to politics: Everyday practice and environmental governance in Veracruz,Mexico

This article argues that everyday practices can matter as much as organized social movements or outright resistance in environmental governance outcomes. While governance has become an important analytical category for understanding the institutional and epistemological systems through which resources are accessed and managed, existing characterizations of environmental governance are based on organized social movements and/or institutional re-scalings. This research reveals how state strategies to govern resources and reorder space were thwarted by the everyday practices of both farmers and state actors. Using a case study from a historic coffee-producing region in Veracruz, Mexico, this article presents ethnographic data to demonstrate how government attempts to control the environment are bound together in mutually constitutive processes of transformation with the actual places, peoples, and practices that make up the landscape.     

The distribution of total and methylmercury concentrations in soils near the Idrija mercury mine, Slovenia, and the dependence of the mercury concentrations on the chemical composition and organic carbon levels of the soil

Although the mining activity of the Idrija mine in Slovenia ceased in 1995, a large amount of mining dregs containing high concentrations of mercury remains in the area. The mining dregs were transported with river flow and deposition along the Idrija River. To estimate the dispersion and change in the chemical form of mercury, a total of 28 soil core samples were taken around the river. The individual core samples were separated into layers for the analysis of their chemical composition, carbon contents, total mercury (T-Hg) and methylmercury (MeHg) concentrations. The chemical composition measured by X-ray fluorescence spectrometry was useful to estimate the dispersion of tailings: the fluvial terrace soil had a chemical composition similar to that of the tailings and could be distinguished clearly from the forest soil. The highest T-Hg concentration, 1,100 mg kg⁻¹, was observed in the fluvial terrace soil near the mine. Although the concentration decreased gradually along with distance from the mine, concentrations higher than 200 mg kg⁻¹ of T-Hg were still observed in the fluvial terrace soil approximately 20 km downstream from the mine. In the vertical distribution of T-Hg in the hillslope soil, a higher value was observed in the upper layers, which suggests the recent atmospheric deposition of mercury. The concentration of MeHg was the lowest at the riverside and higher in the hillslope soil, which was the opposite of the T-Hg distribution. The total organic carbon content tracked similarly with the distribution of MeHg and a linear relation with a significantly high correlation coefficient was obtained. The distinction may be related to the different dispersion process of mercury, and the organic carbon contents may be an important factor for MeHg formation.     

Material characteristics and deterioration evaluation for the 13th century Korean stone pagoda of Magoksa temple

This study focused on the quantitative deterioration evaluation for the Magoksa temple stone pagoda of the thirteenth century in Korea, based on the deterioration map by precise observation and ultrasonic velocity measurements. The stone pagoda is composed mainly of fine-grained quartz diorite with some granodiorite used in the second story and dew bowl, and the replacement stone for restoration in the basement is biotite granite. The deterioration map and the 2D contour map projecting ultrasonic velocity showed that the most serious deterioration was to the north face of the pagoda, which has about 81.2% deterioration rate and a low velocity range compared with the other directions. Thus, it is required to prepare conservation schemes to reduce deterioration and reinforce the structure. It is also required to carry out ground exploitation for calculation of load carrying strength and ground strength together with continuous structural monitoring. The results will be important for the stable and long-term conservation of the pagoda and will further serve to establish scientific conservation systems of stone cultural heritages in the future.     

Assessing homogeneous regions relative to drought class transitions using an ANOVA-like inference. Application to Alentejo, Portugal

In the present study, an ANOVA-like inference technique is used aiming at to assess if Alentejo, southern Portugal, could be considered a homogeneous region for drought management purposes. First, Alentejo was divided into four sub-regions according to latitude (north and south), and longitude (west and east). Inside each sub-region, 10 weather stations were considered. The time series of the Standardized Precipitation Index (SPI) were obtained for these stations using precipitation data for the period 1932–1999 (67 years). Contingency tables for the transitions between SPI drought classes were obtained for these time series. Loglinear models were fitted to these contingency tables to estimate the probabilities for drought class transitions. An ANOVA-like inference was applied considering the four sub-regions like treatments of a two way layout with two factors, latitude and longitude, each one with two levels, north and south, and west and east respectively. The weather stations of each sub-region were treated as replicates. Significant differences between west and east were found, that allowed to consider that Alentejo could be composed by two sub-regions.     

Geochemical evidence of hydrothermal recharge in Lake Baringo,central Kenya Rift Valley

Lake Baringo, a freshwater lake in the central Kenya Rift Valley, is fed by perennial and ephemeral rivers, direct rainfall, and hot springs on Ol Kokwe Island near the centre of the lake. The lake has no surface outlet, but despite high evaporation rates it maintains dilute waters by subsurface seepage through permeable sediments and faulted lavas. New geochemical analyses (major ions, trace elements) of the river, lake, and hot spring waters and the suspended sediments have been made to determine the main controls of lake water quality. The results show that evaporative concentration and the binary mixing between two end members (rivers and thermal waters) can explain the hydrochemistry of the lake waters. Two zones are recognized from water composition. The southern part of the lake near sites of perennial river inflow is weakly influenced by evaporation, has low total dissolved species (TDS), and has a seasonally variable load of mainly detrital suspended sediments. In contrast, waters of the northern part of the lake show evidence for strong evaporation (TDS of up to eight times inflow). Authigenic clay minerals and calcite may be precipitating from those more concentrated fluids. The subaerial hot‐spring waters have a distinctive chemistry and are enriched in some elements that are also present in the lake water. Comparison of the chemical composition of the inflowing surface waters and lake water shows (1) an enrichment of some species (HCO₃^?, Cl, SO₄^2?, F, Na, B, V, Cr, As, Mo, Ba and U) in the lake, (2) a depletion in SiO₂ in the lake, and (3) a possible hydrothermal origin for most F. The rare earth element distribution and the F/Cl and Na/Cl ratios give valuable information on the rate of mixing of the river and hydrothermal fluids in the lake water. Calculations imply that thermal fluids may be seeping upward locally into the lake through grid‐faulted lavas, particularly south of Ol Kokwe Island. Copyright © 2006 John Wiley & Sons, Ltd.     

The dynamic neptunian ring arcs: evidence for a gradual disappearance of Liberté and resonant jump of courage

We present Adaptive Optics observations of Neptune's ring system at 1.6 and 2.2 μm, taken with the 10-m W.M. Keck II telescope in July 2002 and October 2003. We recovered the full Adams and Le Verrier rings for the first time since the Voyager era (1989), and show that the overall appearance of these rings did not change much, except for the ring arcs. Both the location and intensity of all arcs changed drastically relative to trailing arc Fraternité, which has a mean orbital motion of 820.1118 ± 0.0001 deg/day, equal to that of Nicholson et al.'s (1995, Icarus 113, 295-330) solution 2. Our data suggest that all arcs may have decayed over the last decade, while Liberté, in 2003, may be on the verge of disappearing completely. The observed changes in the relative intensities and locations of all arcs further indicate that material is migrating between resonance sites; leading arc Courage, for example, has jumped ∼8°, or, when adopting Namouni and Porco's (2002, Nature 417, 45-47) CER (corotation eccentricity resonance) theory, it advanced by one full corotation potential maximum. Overall, our observations reveal a system that is surprisingly dynamic, and no comprehensive theory exists as of yet that can explain all the observed intricacies.     

Tectonic evolution of an intraplate basin: the Lower Tagus Cenozoic Basin,Portugal

This article focuses on the reinterpretation of well, seismic reflection, magnetic, gravimetric, surface wave and geological surface data, together with the acquisition of seismic noise data to study the Lower Tagus Cenozoic Basin tectono‐sedimentary evolution. For the first time, the structure of the base of the basin in its distal and intermediate sectors is unravelled, which was previously only known in the areas covered by seismic reflection data (distal and small part of intermediate sectors). A complex geometry was found, with three subbasins delimited by NNE‐SSW faults and separated by WNW‐ESE to NW‐SE oriented horsts. In the area covered by seismic reflection data, four horizons were studied: top of the Upper Miocene, Lower to Middle Miocene top, the top of the Palaeogene and the base of Cenozoic. Seismic data show that the major filling of the basin occurred during Upper Miocene. The fault pattern affecting Neogene and Palaeogene units derived here points to that of a polyphasic basin. In the Palaeogene, the Vila Franca de Xira (VFX) and a NNE‐SSW trending previously unknown structure (ABC fault zone) probably acted as the major strike‐slip fault zones of the releasing bend of a pull‐apart basin, which produced a WNW‐ESE to NW‐SE fault system with transtensional kinematic. During the Neogene, as the stress regime rotated anticlockwise to the present NW‐SE to WNW‐ESE orientation, the VFX and Azambuja fault zones acted as the major transpressive fault zones and Mesozoic rocks overthrusted Miocene sediments. The reactivation of WNW‐ESE to NW‐SE fault systems with a dextral strike‐slip component generated a series of horsts and grabens and the partitioning of the basin into several subbasins. Therefore, we propose a polyphasic model for the area, with the formation of an early pull‐apart basin during the Palaeogene caused by an Iberia–Eurasia plates collision that later evolved into an incipient foreland basin along the Neogene due to a NW‐SE to WNE‐ESE oriented Iberia–Nubia convergence. This convergence is producing uplift in the area since the Quaternary except for the Tagus estuary subbasin around the VFX fault, where subsidence is observed. This may be due to the locking or the development of a larger component of strike‐slip movement of the NNE‐SSW to N‐S thrust fault system with the exception of the VFX fault, which is more favourably oriented to the maximum compressive stress.     

A Chart for Judging Optimal Sample Spacing for Ore Grade Estimation

Mineral deposit grades are usually estimated using data from samples of rock cores extracted from drill holes. Commonly, mineral deposit grade estimates are required for each block to be mined. Every estimated grade has always a corresponding error when compared against real grades of blocks. The error depends on various factors, among which the most important is the number of correlated samples used for estimation. Samples may be collected on a regular sampling grid and, as the spacing between samples decreases, the error of grade estimated from the data generally decreases. Sampling can be expensive. The maximum distance between samples that provides an acceptable error of grade estimate is useful for deciding how many samples are adequate. The error also depends on the geometry of a block, as lower errors would be expected when estimating the grade of large-volume blocks, and on the variability of the data within the region of the blocks. Local variability is measured in this study using the coefficient of variation (CV). We show charts analyzing error in block grade estimates as a function of sampling grid (obtained by geostatistical simulation), for various block dimensions (volumes) and for a given CV interval. These charts show results for two different attributes (Au and Ni) of two different deposits. The results show that similar errors were found for the two deposits, although they share similar features: sampling grid, block volume, CV, and continuity model. Consequently, the error for other attributes with similar features could be obtained from a single chart.