Chemical and environmental compatibility of red mud liners for hazardous waste containment     

D. A. Rubinos  G. Spagnoli  M. T. Barral 《International Journal of Environmental Science and Technology》2016,13(3):773-792

Red mud residue from alumina production has been proposed as an alternative liner material. The chemical and environmental compatibility of red mud upon exposure to representative organic (methanol, heptane, TCE, and acetic acid) and inorganic liquids (CaCl₂ and seawater) was studied. Chemical compatibility assays comprised Atterberg limits and sedimentation and hydraulic conductivity tests for red mud interacted with the chemical liquids, whereas the environmental compatibility was assessed through the leaching of metals from red mud as permeated with the liquids. Methanol greatly reduced the plasticity at concentrations ≥80 % by volume, but it did not increase the hydraulic conductivity of compacted red mud. High concentrations (≥60 % v/v) of acetic acid reduced the plasticity and enhanced the sedimentation of red mud. Conversely, acetic acid concentrations ≤40 % caused dispersion, but damaged the hydraulic properties and structure of red mud. The percolation of a pH 2 acetic acid solution did not adversely affect the hydraulic performance of the red mud liner. Neither diluted heptane nor TCE affected the red mud. However, pure organics suppressed the plasticity and induced aggregation of red mud, suggesting a great detrimental effect on red mud liners. The red mud exhibited great resistance to attack by inorganic salt solutions. Some concerning leaching of metals (primarily Al and Cr) occurred as water, acetic acid, and CaCl₂ solutions percolated through red mud, but effluent metals concentration quickly dropped to permissible levels. In general, red mud exhibited a high resistance against chemical attack; nevertheless, exposure to low-dielectric-constant organic chemicals should be avoided.  相似文献   

Conditioning clayey soils with a dispersant agent for Deep Soil Mixing application: laboratory experiments and artificial neural network interpretation     

Salvatore  Erminio  Modoni  Giuseppe  Spagnoli  Giovanni  Arciero  Michela  Mascolo  Maria Cristina  Ochmański  Maciej 《Acta Geotechnica》2022,17(11):5073-5087

Acta Geotechnica - Plasticity of clays makes Deep Soil Mixing (DSM) problematic due to the tendency of the material to congest the rotating blades, reduce mixing efficiency and remain...  相似文献   

Profiles of the H and K lines of CaII in disk flares     

J. Mckim Malville  Einar Tandberg-Hanssen  Dino Zei 《Solar physics》1969,7(2):253-259

The profiles of the resonance lines of Caii have been studied in two large disk flares and in the surrounding plage. In the brightest portions of the flares no self-reversal in the central emission core was detected; self-reversed cores were present in the less bright portions of the flares. We find that as the intensity of the emission core increases the separation of the H₂ and K₂ peaks decreases monotonically, becoming unobservable at intensities near to 0.90 the local continuum. Possible reasons for the behavior of the H and K lines in flares are considered. It is suggested that the largest density enhancements in flares are found near the strongest magnetic field.  相似文献   

Gully head modelling: A Mediterranean badland case study          下载免费PDF全文

Dino Torri  Jean Poesen  Mauro Rossi  Valerio Amici  Daniele Spennacchi  Cati Cremer 《地球表面变化过程与地形》2018,43(12):2547-2561

Predicting the location of gully heads in various environments is an important step towards predicting gully erosion rates. So far, field data collection and modelling of topographic thresholds for gully head development has mainly focused on gullies that formed in forested areas, rangelands, pastures and cropland. Such information for gullies in badlands however is very scarce. Therefore, this paper aims to extend the database on gully head topographical thresholds through data collection in a badland area and to improve the prediction of gully heads forming at sites with a very low erosion resistance value. For this, we chose a badland site located in central Italy that is characterized by biancana forms and both active and dormant gullies. The definition of the conditions under which present‐day gully heads developed allowed a better modelling of the gully head threshold equation, with modification of a previous model and the exemplification of how to use the updated model. The model shows that the resistance to gully head retreat depends on slope gradient and drainage area at gully heads, land use at the moment of gully development (as numerically expressed using parameters derived from the Runoff Curve Number method), surface rock fragment cover, presence of joints, pipes, and factors/processes affecting detachment rate. This study attempted to better understand environmental conditions that control the development of gully heads in badlands through a combination of field data collection of gully heads, an analysis of land use changes over 10 centuries, focusing on the period 1820–2005, and land use management through repeat photography and a critical examination of historical documents. © 2018 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.  相似文献   

The probabilistic seismic hazard assessment of Germany—version 2016, considering the range of epistemic uncertainties and aleatory variability     

Gottfried Grünthal  Dietrich Stromeyer  Christian Bosse  Fabrice Cotton  Dino Bindi 《Bulletin of Earthquake Engineering》2018,16(10):4339-4395

The basic seismic load parameters for the upcoming national design regulation for DIN EN 1998-1/NA result from the reassessment of the seismic hazard supported by the German Institution for Civil Engineering (DIBt). This 2016 version of the national seismic hazard assessment for Germany is based on a comprehensive involvement of all accessible uncertainties in models and parameters and includes the provision of a rational framework for integrating ranges of epistemic uncertainties and aleatory variabilities in a comprehensive and transparent way. The developed seismic hazard model incorporates significant improvements over previous versions. It is based on updated and extended databases, it includes robust methods to evolve sets of models representing epistemic uncertainties, and a selection of the latest generation of ground motion prediction equations. The new earthquake model is presented here, which consists of a logic tree with 4040 end branches and essential innovations employed for a realistic approach. The output specifications were designed according to the user oriented needs as suggested by two review teams supervising the entire project. Seismic load parameters, for rock conditions of \(v_{S30}\) = 800 m/s, are calculated for three hazard levels (10, 5 and 2% probability of occurrence or exceedance within 50 years) and delivered in the form of uniform hazard spectra, within the spectral period range 0.02–3 s, and seismic hazard maps for peak ground acceleration, spectral response accelerations and for macroseismic intensities. Results are supplied as the mean, the median and the 84th percentile. A broad analysis of resulting uncertainties of calculated seismic load parameters is included. The stability of the hazard maps with respect to previous versions and the cross-border comparison is emphasized.  相似文献   

Erratum to: Partially non-ergodic region specific GMPE for Europe and Middle-East     

Sreeram Reddy Kotha  Dino Bindi  Fabrice Cotton 《Bulletin of Earthquake Engineering》2016,14(8):2435-2435

  相似文献   

A Refinement of the McMillen (1988) Recursive Digital Filter for the Analysis of Atmospheric Turbulence     

Marco Falocchi  Lorenzo Giovannini  Massimiliano de Franceschi  Dino Zardi 《Boundary-Layer Meteorology》2018,168(3):517-523

We present a refinement of the recursive digital filter proposed by McMillen (Boundary-Layer Meteorol 43:231–245, 1988), for separating surface-layer turbulence from low-frequency fluctuations affecting the mean flow, especially over complex terrain. In fact, a straightforward application of the filter causes both an amplitude attenuation and a forward phase shift in the filtered signal. As a consequence turbulence fluctuations, evaluated as the difference between the original series and the filtered one, as well as higher-order moments calculated from them, may be affected by serious inaccuracies. The new algorithm (i) produces a rigorous zero-phase filter, (ii) restores the amplitude of the low-frequency signal, and (iii) corrects all filter-induced signal distortions.  相似文献   

Micropiping processes and biancana evolution in southeast Tuscany, Italy   总被引：1，自引：0，他引：1  

Dino Torri  Rorke Brya 《Geomorphology》1997,20(3-4)

Biancane badlands consisting of small domes dissected by rills and micropipes, with rough disordered microrehef, can be found along the Apennines in Italy. The dominant processes forming biancane differ from those of badlands formed on smectite-rich mudrocks, as micropipes associated with pseudokarstic enlargement of pores and cracks predominate and form the main routes for evacuation of eroded material.Biancana evolution is controlled by water infiltration into intact bedrock, producing an erodible weathering ‘rind’ which is more porous than intact rock. This rind is easily removed by rill or micropipe flow, and erosion is therefore ‘weathering-controlled’, depending on rind production by infiltrating water. Infiltration is initially slow and stepped, due to slow water movement through very small capillary pores in intact rock alternating with rapid filling of macropores and cracks. This occurs due to rapid matrix pore enlargement by dispersion and/or dissolution. The infiltration pattern is accurately reproduced by a model built on progressive development of weathering layers by moisture penetration. Model results are consistent with weathering rind depths and erosion observed in the field, and show that a pipe network can be generated on newly exposed rock by the rainfall of one year.Propagation of the pipe network diverts a progressively larger proportion of runoff into micropipes, expanding weathering rind production within the biancana as well as on the surface. Internal weathering and flow progressively dominate with few unweathered corestones, and the biancana gradually collapses into a penultimate “soufflé-like” form.  相似文献   

The Lago di Varano: Hydrologic Characteristics and Sediment Composition     

Federico Spagnoli  Antonietta Specchiulli  Tommaso Scirocco  Gerardo Carapella  Paolo Villani  Giovanni Casolino  Primiano Schiavone  Massimo Franchi 《Marine Ecology》2002,23(S1):384-394

Abstract. The Lago di Varano is situated on the north side of the Gargano National Park (southeast Italy) and covers a surface area of about 65 km². It communicates with the Adriatic Sea through two artificial canals (Foce Capoiale and Foce Varano) located at the two ends of a long and narrow coastal dune. This work presents preliminary results of four seasonal surveys (1999–2000) carried out to measure chemical and physical parameters of the water column (temperature, salinity, dissolved oxygen and pH) and to analyse a number of biogeochemical characteristics of surface sediments (organic matter, total phosphorus, total nitrogen and total Hg, As, Pb, Cd, Cr, Cu and Ni content). Water analysis indicated poor exchange between the coastal pond and the open sea, limited to autumn and winter. Surface sediments were rich in organic matter, whose distribution was influenced by chemical-physical and hydrodynamic variations in the water column. At the sediment level, the highest values of Cd were found in the central zone of the basin, while the highest Cr values were measured in the central and southeastern areas. With the exception of Cd and Pb, the metal content did not indicate anthropogenic pollution, in particular when compared with the Venice Lagoon and the Central Adriatic Sea.  相似文献   

A review on the behavior of helical piles as a potential offshore foundation system     

Giovanni Spagnoli  Cristina de Hollanda Cavalcanti Tsuha 《Marine Georesources & Geotechnology》2020,38(9):1013-1036

Abstract

Helical piles are used mainly to resist tension forces generated by uplift and overturning moments of various structures, therefore they have been suggested as a potential alternative to driven piles as offshore pile because they provide a large uplift capacity due to the anchor effect of the helix. To date no standards are available for the assessment of the use of helical piles in the offshore environment. State-of-the art installation and uplift capacity assessment is based on field onshore tests on small helical piles. The purpose of this review is to critically evaluate the current knowledge on helical piles considering uplift capacity, cyclic load, installation torque models and the parameters affecting the installation torque, to understand whether they can be considered for potential offshore applications. The paper could be of valuable interest for engineers and contractors involved in the offshore installation of piles.  相似文献