Laboratory development of a vertically oriented penetrometer for shallow seabed characterization

Current site investigation practice for offshore pipeline design relies on soil parameters gathered from boreholes or in situ test soundings to depths of 1–2 m below the mudline. At these depths, the fine-grained seabed is very soft and possesses low undrained strength, which can be difficult to measure. This paper describes a centrifuge test programme undertaken to evaluate the feasibility and performance of a novel penetrometer designed to assess the shallow strength of soft seabed over continuous horizontal profiles. This device is termed the vertically oriented penetrometer (VOP). Tests were performed on a normally consolidated kaolin sample, with the VOP translated horizontally at velocities ranging from 1 to 30 mm/s, after embedding the VOP at 30 and 45 mm depths. All tests involved many cycles of VOP forward and backward movement to assess its potential to derive the ratio of intact to fully remoulded strength. Strength determination is achieved by dragging the VOP at a specified embedment depth along the soil surface, and deriving the soil strength from the measured resistance as if the VOP were a laterally loaded pile. The VOP is shown to yield comparable strength measurements to that of a T-bar penetrometer. The VOP is a potentially valuable addition to the range of tools used to characterize soil strength, both in small-scale centrifuge models and, following practical development, potentially also in the field.

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Ecology and distribution of Tephroseris longifolia subsp. moravica in relation to environmental variation at a micro-scale

Biologia ◽

10.2478/s11756-011-0142-y ◽

2012 ◽

Vol 67 (1) ◽

Cited By ~ 6

Author(s):

Monika Janišová ◽

Katarína Hegedüšová ◽

Pavol Kráľ ◽

Iveta Škodová

Keyword(s):

Competitive Ability ◽

Vascular Plant ◽

Environmental Variation ◽

Small Scale ◽

Soil Parameters ◽

Minor Role ◽

Soil Reaction ◽

Ecological Indicator ◽

Rate Of Increase ◽

And Performance

AbstractTephroseris longifolia subsp. moravica is an endemic endangered taxon of European importance. Within the nine recently known populations it occurs in very specific site conditions of ecotone habitats. In our contribution, we try to quantify its realized niche with regard to the measured components of its biotic and abiotic environment. The main aim was to assess the importance of spatial environmental variation on taxon occurrence and performance and to relate the obtained ecological information to data on taxon abundance and demography. Possible reasons of taxon rarity are discussed, too. Comparison of plot pairs indicated that plots containing the taxon had deeper soil and higher soil Na and Mg contents than plots without it. They also contained higher number of species, especially forbs. Several soil parameters were positively correlated with taxon size and density while light parameters played minor role. Negative correlations between cover of vascular plants, especially grasses and taxon size and density suggest its reduced competitive ability. Vascular plant-based ecological indicator values were set for light (6), temperature (5), continentality (4), moisture (5), soil reaction (7) and nutrients (5). The studied sites differed in topography, soil characteristics (pH, soil Na, K, Ca, P and NH4) and cover of herb litter. Size of taxon populations was negatively related to their finite rate of increase which varied between 1.25 and 2.04 and was most sensitive to demographic parameters related to growth. We conclude, that the studied taxon is not strictly stenotopic as the ranges of several environmental variables were rather wide. We suppose, that the narrow limits of recent taxon occurrence are consequences of its low competitive ability and demographic processes related to germination and seedling establishment. The differing requirements of its ontogenetic stages (seedlings and generative individuals) may define the final limits of its small-scale distribution.

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Fabrication and Performance Evaluation of Small Scale Wood Gas Stove for House Hold Purpose Using Water Boiling Test Method

International Journal of Scientific and Research Publications (IJSRP) ◽

10.29322/ijsrp.9.11.2019.p9587 ◽

2019 ◽

Vol 9 (11) ◽

pp. p9587

Author(s):

Ayalew Bekele Demie ◽

Getachew Hailu wondimagegn ◽

Shemsedin Abubeker

Keyword(s):

Performance Evaluation ◽

Test Method ◽

Small Scale ◽

Water Boiling Test ◽

And Performance

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Sensitivity and Performance Analyses of the Distributed Hydrology–Soil–Vegetation Model Using Geomorphons for Landform Mapping

Water ◽

10.3390/w13152032 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2032

Author(s):

Pâmela A. Melo ◽

Lívia A. Alvarenga ◽

Javier Tomasella ◽

Carlos R. Mello ◽

Minella A. Martins ◽

...

Keyword(s):

Complex Terrain ◽

Overland Flow ◽

Hydrological Model ◽

Model Performance ◽

Soil Parameters ◽

Vegetation Model ◽

Landform Classification ◽

Physically Based ◽

And Performance ◽

Streamflow Simulation

Landform classification is important for representing soil physical properties varying continuously across the landscape and for understanding many hydrological processes in watersheds. Considering it, this study aims to use a geomorphology map (Geomorphons) as an input to a physically based hydrological model (Distributed Hydrology Soil Vegetation Model (DHSVM)) in a mountainous headwater watershed. A sensitivity analysis of five soil parameters was evaluated for streamflow simulation in each Geomorphons feature. As infiltration and saturation excess overland flow are important mechanisms for streamflow generation in complex terrain watersheds, the model’s input soil parameters were most sensitive in the “slope”, “hollow”, and “valley” features. Thus, the simulated streamflow was compared with observed data for calibration and validation. The model performance was satisfactory and equivalent to previous simulations in the same watershed using pedological survey and moisture zone maps. Therefore, the results from this study indicate that a geomorphologically based map is applicable and representative for spatially distributing hydrological parameters in the DHSVM.

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Small-scale plasticity of ultra-fine grained alloy and nanostructured nanocomposite: Ambient and elevated-temperature nanoindentation

Materials Science and Engineering A ◽

10.1016/j.msea.2021.140873 ◽

2021 ◽

Vol 807 ◽

pp. 140873

Author(s):

F. Khodabakhshi ◽

A.P. Gerlich ◽

D. Verma ◽

M. Nosko ◽

M. Haghshenas

Keyword(s):

Elevated Temperature ◽

Small Scale ◽

Fine Grained

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Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia revealed by advanced InSAR

10.5194/nhess-2018-211 ◽

2018 ◽

Author(s):

Nicholas J. Roberts ◽

Bernhard T. Rabus ◽

John J. Clague ◽

Reginald L. Hermanns ◽

Marco-Antonio Guzmán ◽

...

Keyword(s):

Ground Deformation ◽

Ground Surface ◽

Slope Instability ◽

Small Scale ◽

Spatial And Temporal Patterns ◽

La Paz ◽

Fine Grained ◽

Measured Displacement ◽

Optical Satellite Images ◽

Displacement Patterns

Abstract. We characterize and compare creep preceding and following the 2011 Pampahasi landslide (∼ 40 Mm3 ± 50 %) in the city of La Paz, Bolivia, using spaceborne RADAR interferometry (InSAR) that combines displacement records from both distributed and point scatterers. The failure remobilised deposits of an ancient landslide in weakly cemented, predominantly fine-grained sediments and affected ∼ 1.5 km2 of suburban development. During the 30 months preceding failure, about half of the toe area was creeping at 3–8 cm/a and localized parts of the scarp area showed displacements of up to 14 cm/a. Changes in deformation in the 10 months following the landslide are contrary to the common assumption that stress released during a discrete failure increases stability. During that period, most of the landslide toe and areas near the headscarp accelerated, respectively, to 4–14 and 14 cm/a. The extent of deformation increased to cover most, or probably all, of the 2011 landslide as well as adjacent parts of the slope and plateau above. The InSAR-measured displacement patterns – supplemented by field observations and by optical satellite images – indicate that kinematically complex, steady-state creep along pre-existing sliding surfaces temporarily accelerated in response to heavy rainfall, after which the slope quickly achieved a slightly faster and expanded steadily creeping state. This case study demonstrates that high-quality ground-surface motion fields derived using spaceborne InSAR can help to characterize creep mechanisms, quantify spatial and temporal patterns of slope activity, and identify isolated small-scale instabilities. Characterizing slope instability before, during, and after the 2011 Pampahasi landslide is particularly important for understanding landslide hazard in La Paz, half of which is underlain by similar, large paleolandslides.

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Solid Form and Phase Transformation Properties of Fexofenadine Hydrochloride during Wet Granulation Process

Pharmaceutics ◽

10.3390/pharmaceutics13060802 ◽

2021 ◽

Vol 13 (6) ◽

pp. 802

Author(s):

Suye Li ◽

Hengqian Wu ◽

Yanna Zhao ◽

Ruiyan Zhang ◽

Zhengping Wang ◽

...

Keyword(s):

Phase Transition ◽

Phase Transformation ◽

Water Content ◽

Scale Up ◽

Small Scale ◽

Dissolution Behavior ◽

Wet Granulation ◽

Water Addition ◽

Granulation Process ◽

And Performance

The quality control of drug products during manufacturing processes is important, particularly the presence of different polymorphic forms in active pharmaceutical ingredients (APIs) during production, which could affect the performance of the formulated products. The objective of this study was to investigate the phase transformation of fexofenadine hydrochloride (FXD) and its influence on the quality and performance of the drug. Water addition was key controlling factor for the polymorphic conversion from Form I to Form II (hydrate) during the wet granulation process of FXD. Water-induced phase transformation of FXD was studied and quantified with XRD and thermal analysis. When FXD was mixed with water, it rapidly converted to Form II, while the conversion is retarded when FXD is formulated with excipients. In addition, the conversion was totally inhibited when the water content was <15% w/w. The relationship between phase transformation and water content was studied at the small scale, and it was also applicable for the scale-up during wet granulation. The effect of phase transition on the FXD tablet performance was investigated by evaluating granule characterization and dissolution behavior. It was shown that, during the transition, the dissolved FXD acted as a binder to improve the properties of granules, such as density and flowability. However, if the water was over added, it can lead to the incomplete release of the FXD during dissolution. In order to balance the quality attributes and the dissolution of granules, the phase transition of FXD and the water amount added should be controlled during wet granulation.

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Effect of portable fine-grained locality on energy efficiency and performance in concurrent search trees

ACM SIGPLAN Notices ◽

10.1145/3016078.2851186 ◽

2016 ◽

Vol 51 (8) ◽

pp. 1-2 ◽

Cited By ~ 1

Author(s):

Ibrahim Umar ◽

Otto J. Anshus ◽

Phuong H. Ha

Keyword(s):

Energy Efficiency ◽

Search Trees ◽

Fine Grained ◽

And Performance

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Design and performance of a small-scale wind turbine exploiting an electret-based electrostatic conversion

Journal of Physics Conference Series ◽

10.1088/1742-6596/646/1/012009 ◽

2015 ◽

Vol 646 ◽

pp. 012009 ◽

Cited By ~ 2

Author(s):

M Perez ◽

S Boisseau ◽

J L Reboud

Keyword(s):

Wind Turbine ◽

Small Scale ◽

And Performance

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Laboratory Model Tests on Dredger Fills by Vacuum Preloading with No Sand Cushion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.170-173.655 ◽

2012 ◽

Vol 170-173 ◽

pp. 655-660

Author(s):

Ya Jun Wu ◽

Jian Bo Yang

Keyword(s):

Fine Particles ◽

Soil Strength ◽

Plasticity Index ◽

Laboratory Model ◽

Soil Parameters ◽

Grain Composition ◽

Vacuum Preloading ◽

Prefabricated Vertical Drains ◽

Water Contents ◽

Sand Cushion

It is difficult to operate on the hydraulic-filled mucky soil foundation which the water content is high, so the vacuum preloading method with no sand cushion is used to deal with the foundation in some areas in China. Although there are still many problems in it’s application, such as, the effective range of the prefabricated vertical drains(PVDs) is small, the surrounding soil is easy to be accumulated and the soil strength increases little. For these problems, a laboratory model test on dredger fills made from the 4th layer of the Shanghai mucky soil by vacuum preloading with no sand cushion is performed. The changes and distributions in the settlement, water contents, permeability, plasticity index and grain composition of the dredger fill are studied in the process of the vacuum preloading. It is found that the water contents and permeability of the soft clay near the PVD (the diameter is about 40 to 50cm) are much lower than the outside, while the content of fine particles, plasticity index and soil strength near the PVD is much higher than the others. The measured data shows that the fine particles gather to a soil column at the center of the PVD under the action of vacuum negative pressure, then the permeability and the grain composition of the soil around the PVD is changed. As a result, soil parameters are not evenly distributed. Finally, some suggestions about how to reduce the non-uniformity are proposed.

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