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Zonal Jets in Rotating Shallow Water Turbulence
G. Di Nitto,
S. Espa,
A. Cenedese
Issue:
Volume 2, Issue 2, April 2013
Pages:
23-30
Abstract: During the last three decades, the appearance of multiple zonal jets in planetary atmospheres and in the Earth’s oceans has widely studied. Evidences of this phenomenon were recovered in numerical simulations [1], laboratory experi-ments [2-4] and in field measurements of giant planets’ atmosphere [5]. Recent studies have revealed the presence of zonation also in the Earth’s oceans; in fact, zonal jets were recovered in the outputs of Oceanic General Circulation Models-GCMs [6] and from satellite altimetry observations [7]. In previous works [3-4], we have investigated the impact of several experimental parameters on jets organization both in decaying and forced regimes. This work shows new results in the context of continuously forced flows obtained performing experiments in a bigger domain. The experimental set-up consists of a rotating tank where the initial distribution of vorticity is generated via the Lorentz force in an electromagnetic cell and the latitudinal variation of the Coriolis parameter is simulated by the parabolic profile assumed by the free surface of the rotating fluid. The velocity fields were measured using an image analysis technique. The flow is characterized in terms of zonal and radial flow pattern, flow variability and jet scales.
Abstract: During the last three decades, the appearance of multiple zonal jets in planetary atmospheres and in the Earth’s oceans has widely studied. Evidences of this phenomenon were recovered in numerical simulations [1], laboratory experi-ments [2-4] and in field measurements of giant planets’ atmosphere [5]. Recent studies have revealed the presence of z...
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Influence of the Design on Slope Stability in Solid Waste Landfills
Francisco J. Colomer-Mendoza,
Joan Esteban-Altabella,
Ferran García-Darás,
Antonio Gallardo-Izquierdo
Issue:
Volume 2, Issue 2, April 2013
Pages:
31-39
Abstract: This paper presents, firstly, the influence of the geometry of a slope in the safety factor (SF). In order to do this, the SF is compared among three types of slopes: with berms every 7 m high and a dam at the toe, without berms and with a dam at the toe, and without berms nor dams. It was observed that, for the same inclination, the berms do not significantly influence the stability. However, the construction of an earth dam at the base increases safety, especially with little height and slope in waste with poor mechanical properties. On the other hand, a set of diagrams to learn, quickly and easily, the safety factor of a landfill slope has been developed. Thus, this set of diagrams allows calculations from the SF height (from 17 to 80 m) and slope inclination (from 45° to 14°) with values of effective cohesion of the waste (C'o) from 1 to 3 t/m2 and effective friction angle (') of 10° to 25°.
Abstract: This paper presents, firstly, the influence of the geometry of a slope in the safety factor (SF). In order to do this, the SF is compared among three types of slopes: with berms every 7 m high and a dam at the toe, without berms and with a dam at the toe, and without berms nor dams. It was observed that, for the same inclination, the berms do not s...
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Recycling of Solid Waste Material In Hong Kong: I. Properties of Modified Clay Mineral Waste Material and its Application for Removal of Cadmium In Water
Y. N. Jiang,
H. D. Ruan,
S. Y. Lai,
C. H. Lee,
C. F. Yu,
Z. Wu,
X. Chen,
S. He
Issue:
Volume 2, Issue 2, April 2013
Pages:
40-46
Abstract: Large quantities of solid waste are disposed to landfill sites in Hong Kong each year and these landfill sites will be filled within five years. Recycling of solid waste material has become a very urgent task and evaluation of its application in environmental remediation has been functioned recently. Mineral-containing waste material, which is one of the common solid waste components to be disposed to landfill sites in Hong Kong, was used to produce the modified clay mineral waste material (MCMWM) for removal of cadmium (Cd) in water. The physical, chemical and mineralogical properties of MCMWM related to Cd adsorption were investigated using scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET specific surface area (SSA) and pore size distribution (PSD) measurements, and inductively coupled plasma optical emission spectroscopy (ICP-OES). The particle size of MCMWM ranged from less than a few to tens of micrometers, and the particles had rough surface and structural defects. Specific surface area was 5.6 m2/g, with different types of external and internal pores being observed. The minerals in MCMWM were mainly 2:1 clay minerals. Smectite, illite, chlorite, feldspars, quartz, and calcium hydroxide were detected. Heavy metals including arsenic, cadmium, chromium, mercury and lead detected in MCMWM were much lower than the maximum allowed level for each kind of heavy metal based on the Dutch Standard that has been used worldwide. Cadmium adsorption by MCMWM was very rapid in solid/liquid interface as up to 90% of Cd2+ can be adsorbed within half hour of reaction. The amount of Cd2+ adsorbed increased but the rate of adsorption decreased with increasing concentration of Cd2+ in solution. The Cd2+ adsorption was related to the surface structure and chemistry, including SSA, PSD, surface defect, charge and bonding in MCMWM.
Abstract: Large quantities of solid waste are disposed to landfill sites in Hong Kong each year and these landfill sites will be filled within five years. Recycling of solid waste material has become a very urgent task and evaluation of its application in environmental remediation has been functioned recently. Mineral-containing waste material, which is one...
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Method for Determining the Potential Strain Energy Stored in the Earth before a Large Earthquake
Issue:
Volume 2, Issue 2, April 2013
Pages:
47-57
Abstract: This paper describes a technique for determining the potential energy of deformed material around a future earthquake rupture, with this energy being stored during the precursory period. The basic parameters are the following: rupture length on the Earth’s surface after the earthquake has occurred , rupture depth h, and the relative block movement along the rupture strike line . We compared the results for 44 large earthquakes with those derived by determining seismic wave energy from earthquake magnitude.
Abstract: This paper describes a technique for determining the potential energy of deformed material around a future earthquake rupture, with this energy being stored during the precursory period. The basic parameters are the following: rupture length on the Earth’s surface after the earthquake has occurred , rupture depth h, and the relative block movement...
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Unsaturated Volcanic Tephra and Its Effect for Soil Movement in El Salvador
José Alexander Chávez Hernández,
José Alexander Chávez Hernández,
Jiři Šebesta,
Lubomir Kopecky,
Reynaldo López Landaverde,
José Landaverde
Issue:
Volume 2, Issue 2, April 2013
Pages:
58-65
Abstract: In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera are the more problematic region in the Metropolitan Area of San Salvador. In El Salvador during the summer and rainy season the groundwater level remains low in most of the areas, this means that the soils in the country are unsaturated and there are capillary forces that act on the soil structure making that an “apparent cohesion” (suction) improve the strength of the soil; this circumstance makes that the slopes are almost vertical and temporally stable, but will collapse when wetted or during seismic events. To that problematic is possible to add that the majority of the water pipelines are in bad condition and when they fail is possible to expect the collapse of entire streets or houses. Wetting of the soil is likely to occur following construction development, because evaporation is reduced by covering the ground surface with a structure. For unsaturated soils the use of two independent stress variables: net stress and suction are needed. Suction values of TBJ “G” unit of the proximal facie were obtained using pressure plate, tensiometer and filter paper to obtain a Soil-Water Retention Curve (SWRC); the use of this curve into finite elements software can help to obtain the shear strength and permeability properties. For monitoring, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed, because it could be a way to build a field methodology for early warning system for the slopes for urban planning and risk assessment.
Abstract: In El Salvador during the rainy season or when major earthquakes affect the area, processes like mass move-ments, liquefaction, erosion and floods affect the territory leaving environmental, social and economic damages. The vol-canic tephras called "Tierra Blanca Joven" (TBJ) which is a product of the last plinian eruption of the Ilopango Caldera a...
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