Modeling the effect of flow-induced mechanical erosion during coffee filtration

A long-term sediment budget (1947−1985) for northern Richards Island shows that, when ground ice and offshore erosion are accounted for, there is a near balance between headland erosion and coastal deposition. Excess ice constitutes about 20% of the total volume of eroded material from the headlands, with massive ground ice contributing nearly 9% and segregated ice lenses and ice wedges making up the remainder. Coastal response to major storms in 1987 and 1993 suggests that erosion is episodic, with short periods of intense disruption followed by readjustment of cliff profiles. Processes characteristic of this environment include mechanical erosion of ice-bonded sediments creating unstable erosional niches, mechanical failure of niches along ice-wedge planes, and longer term thermal erosion of ice-bonded sediments. Where ice contents are high, localized thaw slumps initiated by coastal erosion may retreat at rates substantially higher than those observed at other sections of the coast. Cliff-top retreat rates may be out of phase with storm-event chronology.

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Effect of Organo Montmorillonite Nanoclay on Mechanical Properties Thermal Stability and Ablative Rate of Carbon fiber Polybenzoxazine Resin Composites

Defence Science Journal ◽

10.14429/dsj.71.16630 ◽

2021 ◽

Vol 71 (5) ◽

pp. 682-690

Author(s):

Golla Rama Rao ◽

Ivaturi Srikanth ◽

K. Laxma Reddy

Keyword(s):

Thermal Stability ◽

Carbon Fiber ◽

Ablation Rate ◽

Constant Heat Flux ◽

Type I ◽

Type Ii ◽

Weight Percentage ◽

Mechanical Erosion ◽

Interlaminar Shear ◽

Rate Behaviour

Organo-Montmorillonite (o-MMT) nanoclay added polybenzoxazine resin (type I composites) were prepared with varying amounts of clay (0, 1, 2, 4 and 6 wt %). Clay dispersion, changes in curing behaviour and thermal stability were assessed in type I composites. Findings from these studies of type I composites were used to understand thermal stability, mechanical, and mass ablation rate behaviour of nanoclay added carbon fiber reinforced polybenzoxazine composites (type II). Interlaminar shear strength and flexural strength of type II composites increase by 25% and 27%, respectively at 2 wt% addition of clay. An oxy-acetylene torch test with a constant heat flux of 125 w/cm2 was used to investigate mass ablation rate of type II composites. The ablation rate has increased as the weight percentage of clay has increased. This is contradicting to type I composites with up to 6 wt% clay and type II composites with up to 4 wt% clay, which have improved thermal stability. The microstructure of the ablated composites was examined using scanning electron microscopy. Increased ablation rates are due to the reaction of charred matrix with nanoclay, which exposes bare fibers to the ablation front, resulting in higher mechanical erosion losses.

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Evaluation of Mechanical and Tribological properties of Biowaste and Biowaste Based Silica Particulate Epoxy Composites

10.21203/rs.3.rs-511554/v1 ◽

2021 ◽

Author(s):

V. Pranay ◽

S. Ojha ◽

Raghavendra G ◽

G. Dheeraj ◽

A. Anjali

Keyword(s):

Rice Husk ◽

Silica Content ◽

Filler Loading ◽

Epoxy Composites ◽

Erosion Wear ◽

Wear Properties ◽

Pure Epoxy ◽

Mechanical And Tribological Properties ◽

Silica Fillers ◽

Mechanical Erosion

Abstract This paper reports the mechanical-erosion wear properties of extracted silica from Biowaste (rice husk) and pure rice husk-filled epoxy composites. A comparison is made on the influence of dispersed silica and rice husk particles on the properties of the epoxy composites. The composites are fabricated by hand lay-up process. The specimens are tested as per the ASTM standards for three different filler loadings of each silica and rice husk separately (2,4 and 6wt%). It is perceived that with the increase in the rice husk filler loading in epoxy, there is a decline in tensile, flexural, and erosion wear properties. It is also evident that, with the increase in silica content until 6%, the tensile and flexural strength have displayed consistent enhancement. Alongside, erosion results confirm that the properties of the pure epoxy had exhibited transition from semi-brittle to ductile nature due to the addition of silica fillers.

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Late Pleistocene Detrital Sediment Yield of the Jura Glacier, France

Quaternary Research ◽

10.1006/qres.2001.2243 ◽

2001 ◽

Vol 56 (1) ◽

pp. 51-61 ◽

Cited By ~ 7

Author(s):

Jean-François Buoncristiani ◽

Michel Campy

Keyword(s):

Late Pleistocene ◽

Sediment Yield ◽

Source Area ◽

Sediment Source ◽

Glacial Period ◽

Denudation Rate ◽

Lake System ◽

Mechanical Erosion ◽

Detrital Sediment ◽

Proglacial Lake

AbstractMeasures of present-day glacial erosion vary widely with the technique employed. This paper quantifies the glacial material trapped in a proglacial lake during the Würm glacial period. The Combe d'Ain site was occupied by a meltwater lake where all the detrital material entering it from the Jura glacier accumulated. Sediment yield is computed from three factors: (1) the size of the sediment source area, (2) the length of time the system operated, and (3) the volume of sediment trapped. The sediment budget of the lake system suggests a detrital sediment yield of 4400±1700 metric tons per square kilometer and per calendar year. This represents a denudation rate of 1.6±0.6 mm per year, illustrating that mechanical erosion by the Jura glacier is more intensive than other processes of erosion.

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Quantification of biogeomorphic interactions between small-scale sediment transport and primary vegetation succession on proglacial slopes of the Gepatschferner, Austria

10.5194/egusphere-egu21-16278 ◽

2021 ◽

Author(s):

Stefan Haselberger ◽

Lisa-Maria Ohler ◽

Jan-Christoph Otto ◽

Robert R. Junker ◽

Thomas Glade ◽

...

Keyword(s):

Sediment Transport ◽

Sediment Yield ◽

Plant Cover ◽

Species Abundance ◽

Small Scale ◽

Vegetation Composition ◽

Mechanical Erosion ◽

Successional Stages ◽

Three Stages ◽

Specific Sediment Yield

Proglacial slopes provide suitable conditions to observe the co-development of abiotic and biotic systems. The frequency and magnitude of geomorphic processes and composition of plants govern this interplay, which is described in the biogeormorphic feedback window for glacier forelands. The study sets out to quantify small-scale sediment transport via mechanical erosion plots along a plant cover gradient and to investigate the multidirectional interactions between abiotic and biotic processes. We aim to generate quantitative data to test the biogeomorphic feedback window.Small-scale biogeomorphic interactions were investigated on 30 test plots of 2 x 3 m size on proglacial slopes of the Gepatschferner (Kaunertal) in the Austrian Alps during snow-free summer months over three consecutive years. The experimental plots were established on slopes along a plant cover gradient. A detailed vegetation survey was carried out to capture biotic conditions and specific sediment yield was measured at each plot. Species abundance and composition at each site, as well as plant functional types reflected successional stages.We observed a strong decline in geomorphic activity on plots with above 30% plant cover. Mean monthly rates of specific sediment yield decreased from 111 g m-2 to 37 g m-2. Non-metric multidimensional scaling showed distinct vegetation composition for the three stages of biogeomorphic succession. Quantified process rates and observed vegetation composition support the concept of biogeomorphic feedback windows. The findings help to narrow down a stage during succession where the importance of biotic processes start to dominate.

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