Characterization of a Catastrophic Flood Sediment Layer: Geological, Geotechnical, Biological, and Geochemical Signatures

2008 ◽  
pp. 87-87-15 ◽  
Author(s):  
H Tremblay ◽  
G Desrosiers ◽  
J Locat ◽  
A Mucci ◽  
É Pelletier
Keyword(s):  
Sediment Layer ◽  
Catastrophic Flood

scholarly journals Exposing Practical, Psychological, and Pedagogical Shadow Sides of Experiential Learning

2018 ◽  
Vol 42 (6) ◽  
pp. 761-771
Author(s):  
April Wright ◽  
Paul Hibbert ◽  
Ross Strong ◽  
Marissa Edwards
Keyword(s):  
Experiential Learning ◽  
Flood Event ◽  
First Person ◽  
General Applicability ◽  
Catastrophic Flood ◽  
Person Experience ◽  
First Person Experience

This article is based first-person experience with experiential learning (EL) practices in an undergraduate introductory management course. We consider how a challenging EL activity, based on volunteering during recovery from a catastrophic flood event, exposed three shadow sides of EL. These shadow sides of EL, which often remain hidden to educators, are practical, psychological, and pedagogical. We provide a characterization of each of these shadow sides and outline strategies for managing them. We also discuss the general applicability of our insights, including tentative theoretical extensions to Kolb’s EL theory. We conclude by considering the potential for the shadow sides of EL to emerge in circumstances that are less confronting and extreme than those encountered by our students.

Clays and zeolite authigenesis in sediments from the flank of the Juan de Fuca Ridge

Clay Minerals ◽  
2002 ◽  
Vol 37 (1) ◽  
pp. 143-155 ◽  
Author(s):  
M. D. Buatier ◽  
A. M. Karpoff ◽  
D. Charpentier
Keyword(s):  
Juan De Fuca Ridge ◽  
Sediment Layer ◽  
Mechanism Of Formation ◽  
Ridge Axis ◽  
Calcium Carbonates ◽  
Fuca Ridge ◽  
Stable Isotopic ◽  
Juan De Fuca

AbstractThis study focuses on the mineralogical and chemical analysis of sediments overlying basaltic basement through which seawater circulates (ODP Leg 168, flank of the Juan de Fuca Ridge). A SEM and TEM-EDX study of the authigenic clays and zeolites allowed the characterization of the hydrothermal phases and the determination of their mechanism of formation. Silicate authigenesis related to hydrothermal alteration of sediment was observed in the sediment layer just above basement at sites located >30 km from the ridge axis. This sediment alteration is particularly intense at Site 1031 where authigenic formation of Fe-Mg- rich smectites (montmorillonite and saponite) and zeolites occur, linked to the dissolution of biogenic calcite. Vertical advection of basement fluid through the sediment column is required to produce this alteration. This process is still active at Site 1031, based on systematic variations in porewater profiles and temperatures obtained from stable isotopic data on calcium carbonates, and the nature of authigenic minerals.

scholarly journals Remediation of Caldas site by natural attenuation

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Renata Dias Abreu Chaves ◽  
Paulo Cesar Horta Rodrigues ◽  
Ana Claudia Queiroz Ladeira
Keyword(s):  
Mine Drainage ◽  
Water Reservoir ◽  
Acid Volatile Sulfide ◽  
Uranium Mine ◽  
Sediment Layer ◽  
Atmospheric Conditions ◽  
Bacterial Oxidation ◽  
Natural Remediation

Acid mine drainage (AMD) is one of the main environmental issue caused by chemical and bacterial oxidation of pyrite (FeS2) and other sulfite minerals when exposed to atmospheric conditions during mining. In Brazil, AMD occurs in a former uranium mine and contains radionuclides and other elements, which are precipitated from acidic water by liming. Due to the inefficiency of the treatment, contaminants overflow to the water reservoir of Indústrias Nucleares do Brasil – INB in Caldas. The multiplicity of interactions that can occur between the contaminants and the sediments of the reservoir requires a broader approach in order to understand the fixation and/or transport of these elements. In this work the natural remediation approach is reviewed and an initial chemical and radiochemical characterization of the reservoir sediments is presented. Uranium was determined by spectrophotometry, Ra-226, Ra-228 and Pb-210 by gamma spectrometry and zinc by ICP-OES. Twenty-six sediment samples were collected in the reservoir and a bathymetry survey by sonar was performed to determine the thickness of the sediment layer. All the data were processed using the ArcGIS program. To assess the potential mobility and bioavailability of contaminants and to study the role of bacterial sulfate reduction in the immobilization of these contaminants, Acid-volatile sulfide (AVS) analyzes will be performed as a further step.

scholarly journals Characterization of sediment layer composition in a shallow lake: from open water zones to reed belt areas

2014 ◽  
Vol 11 (11) ◽  
pp. 12627-12657
Author(s):  
I. Kogelbauer ◽  
W. Loiskandl
Keyword(s):  
Shallow Lake ◽  
Open Water ◽  
Penetration Resistance ◽  
Measuring System ◽  
High Water Content ◽  
Sediment Layer ◽  
Soil Physics ◽  
Layer Composition

Abstract. Lake sediment characterization, a pre-requirement for the vulnerability assessment of lake ecosystems, demands reliable in situ methods for the characterization of the sediment layer composition. A unified characterization of lake sediments within different lake ecotopes (open water, open water patches within the reed, and the reed) is still a challenge. Each ecotope is covered by different classical scientific disciplines (hydrography and terrestrial remote sensing to soil physics) with their specific characterization methods. However, a complementary tool that bridges the gap between land- and hydrographic surveying methods is still missing. Therefore a combination of soil physical sensors (a capacitive sensor and a cone penetrometer) in a measuring system (CSPS) was introduced. CSPS is a non-acoustic device for the rapid in situ delineation of water-mud-consolidated lakebed interfaces. The system was successfully applied across the different ecotopes at the Neusiedler See, a well-mixed shallow lake rich in fine-grained sediments. The geo-referenced vertical CSPS profiles show ecotope-specific layer composition. The effect of wind induced turbidity, particle size, and electrical conductivity were analysed. The water–mud interface was precisely delineated at the open water due to a persistent high water content gradient, equivalent to a lutocline. The penetration resistance for open water showed either a shallow and highly-compacted consolidated lakebed or a consolidated lakebed with a partially compacted layer above; while in the reed the penetration resistance smoothly increased until reaching the deepest penetration depths.

scholarly journals Characterization of sediment layer composition in a shallow lake: from open water zones to reed belt areas

2015 ◽  
Vol 19 (3) ◽  
pp. 1427-1438 ◽  
Author(s):  
I. Kogelbauer ◽  
W. Loiskandl
Keyword(s):  
Shallow Lake ◽  
Open Water ◽  
Measuring System ◽  
High Water Content ◽  
Sediment Layer ◽  
Soil Physics ◽  
Lake Ecosystems ◽  
Layer Composition

Abstract. Lake sediment characterization, a prerequisite for the vulnerability assessment of lake ecosystems, demands reliable in situ methods for the characterization of the sediment layer composition. A unified characterization of lake sediments within lake ecotopes (open water, open water patches within the reed, and the reed) is still a challenge. Each ecotope is covered by different classical scientific disciplines (hydrography and terrestrial remote sensing to soil physics) with their specific characterization methods. Recently, a complementary tool that bridges the gap between land and hydrographic surveying methods was introduced. It is a non-acoustic device that combines two soil physical sensors (a capacitive sensor and a cone penetrometer) and GNSS-positioning in a measuring system (CSPS). The CSPS enables rapid in situ delineation of water–mud–consolidated lakebed interfaces. The system was successfully applied across ecotopes at the Neusiedler See, a well-mixed shallow lake rich in fine-grained sediments. The geo-referenced vertical CSPS profiles show ecotope-specific layer composition. The effects of wind-induced turbidity, particle size, and electrical conductivity were analysed. The water–mud interface was precisely delineated at the open water due to a persistent high water content gradient, equivalent to a lutocline. The penetration resistance (PR) for open water showed either a shallow and highly compacted consolidated lakebed or a consolidated lakebed with a partially compacted layer above, while in the reed the PR smoothly increased until reaching the deepest penetration depths.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

1973 ◽  
Vol 31 ◽  
pp. 144-145
Author(s):  
B. H. Kear ◽  
J. M. Oblak
Keyword(s):  
Stable Phase ◽  
Nickel Base Superalloy ◽  
Alloy 718 ◽  
Commercial Alloy ◽  
Precipitate Morphology ◽  
Continuous Precipitation ◽  
Nickel Base ◽  
Base Superalloy ◽  
Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

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