Transformation models for effective friction angle and relative density calibrated based on generic database of coarse-grained soils

2017 ◽  
Vol 54 (4) ◽  
pp. 481-501 ◽  
Author(s):  
Jianye Ching ◽  
Guan-Hong Lin ◽  
Jie-Ru Chen ◽  
Kok-Kwang Phoon
Keyword(s):  
Relative Density ◽  
Friction Angle ◽  
Coarse Grained ◽  
Transformation Models ◽  
Ground Freezing ◽  
Wide Range ◽  
Block Sampling ◽  
Gravelly Soils ◽  
Data Points

This study compiles a generic database of seven parameters, including relative density and friction angle, for coarse-grained soils from 176 studies, covering a wide range of reconstituted and in situ coarse-grained soils. This database, labeled as “SAND/7/2794”, is dominated by data from laboratory reconstituted soils such as Erksak, Hokksund, Monterey, Ottawa, Sacramento River, Ticino, and Tonegawa sands. About 15% of the data points in the database are in situ samples obtained from tube sampling, block sampling, or ground freezing techniques. The correlation behavior among some parameters in the database is consistent with existing transformation models in the literature. Mine tailings, volcanic soils, railroad ballast, gravelly soils with significant cobble or boulder content, and soils with high fines contents are removed from the database because they exhibit inconsistent behavior. Soils subjected to very high effective stresses are also removed from the database. The generic database is adopted to calibrate the bias and variability of existing transformation models. Transformation uncertainties are characterized based on their bias, variability, and the range of applicability.

Estimating in situ relative density and friction angle of nearshore sand from portable free-fall penetrometer tests

2020 ◽  
Vol 57 (1) ◽  
pp. 17-31
Author(s):  
Ali Albatal ◽  
Nina Stark ◽  
Bernardo Castellanos
Keyword(s):  
Strain Rate ◽  
Bearing Capacity ◽  
Relative Density ◽  
Free Fall ◽  
Friction Angle ◽  
Rate Coefficients ◽  
Triaxial Tests ◽  
Site Assessment ◽  
K Value

The friction angle of sand in the nearshore zone of Cannon Beach, Yakutat, Alaska, was estimated from the deceleration measured by a portable free-fall penetrometer (PFFP) at 72 test locations. A correlation between the relative density and PFFP’s maximum deceleration was developed from controlled PFFP deployments into sand of different relative densities. Two approaches were tested: (i) a correlation between relative density and friction angle and (ii) bearing capacity theory. For the former, laboratory vacuum triaxial tests were performed to adjust an existing correlation between relative density and friction angle for the tested nearshore sediments. In situ peak friction angles were then determined using this adjusted correlation and estimates of relative densities. The resulting in situ relative density and friction angle varied between 32%–88% and 44°–56°, respectively. Two bearing capacity–based methods suitable for shallow penetrations were tested. For this approach, equivalents of static cone resistance were determined from the measured decelerations considering the strain rate effect. A range of empirical strain rate coefficients K = 0.1–1.5 were tested. A K value between 0.2 and 0.4 yielded matching results between the two approaches. The estimated friction angles agreed well with expected values and may be applied to problems of sediment transport or early site assessment.

scholarly journals SNARE machinery is optimized for ultrafast fusion

2019 ◽  
Vol 116 (7) ◽  
pp. 2435-2442 ◽  
Author(s):  
Fabio Manca ◽  
Frederic Pincet ◽  
Lev Truskinovsky ◽  
James E. Rothman ◽  
Lionel Foret ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Snare Proteins ◽  
Coarse Grained ◽  
Optimum Number ◽  
Biological Processes ◽  
Cooperative Action ◽  
Fusion Barrier ◽  
Coarse Grained Model ◽  
Wide Range

SNARE proteins zipper to form complexes (SNAREpins) that power vesicle fusion with target membranes in a variety of biological processes. A single SNAREpin takes about 1 s to fuse two bilayers, yet a handful can ensure release of neurotransmitters from synaptic vesicles much faster: in a 10th of a millisecond. We propose that, similar to the case of muscle myosins, the ultrafast fusion results from cooperative action of many SNAREpins. The coupling originates from mechanical interactions induced by confining scaffolds. Each SNAREpin is known to have enough energy to overcome the fusion barrier of 25–35 kBT; however, the fusion barrier only becomes relevant when the SNAREpins are nearly completely zippered, and from this state, each SNAREpin can deliver only a small fraction of this energy as mechanical work. Therefore, they have to act cooperatively, and we show that at least three of them are needed to ensure fusion in less than a millisecond. However, to reach the prefusion state collectively, starting from the experimentally observed half-zippered metastable state, the SNAREpins have to mechanically synchronize, which takes more time as the number of SNAREpins increases. Incorporating this somewhat counterintuitive idea in a simple coarse-grained model results in the prediction that there should be an optimum number of SNAREpins for submillisecond fusion: three to six over a wide range of parameters. Interestingly, in situ cryoelectron microscope tomography has very recently shown that exactly six SNAREpins participate in the fusion of each synaptic vesicle. This number is in the range predicted by our theory.

Interpretation of cone penetration tests — a unified approach

2009 ◽  
Vol 46 (11) ◽  
pp. 1337-1355 ◽  
Author(s):  
P. K. Robertson
Keyword(s):  
State Parameter ◽  
Friction Angle ◽  
Unified Approach ◽  
Cone Penetration ◽  
Cone Resistance ◽  
Cone Penetration Tests ◽  
Wide Range ◽  
Soil Sensitivity ◽  
Critical Regions

The electric cone penetration test (CPT) has been in use for over 40 years and is growing in popularity in North America. This paper provides some recent updates on the interpretation of some key geotechnical parameters in an effort to develop a more unified approach. Extensive use is made of the normalized soil behaviour type (SBTn) chart based on normalized cone resistance (Qt) and normalized friction ratio (Fr). Updates are provided regarding the normalization process and its application to the identification of soil type. The seismic CPT has provided extensive data linking CPT net cone resistance to shear-wave velocity and soil modulus. New correlations are presented in the form of contours of key parameters on the SBTn chart. These new relationships enable a more unified interpretation of CPT results over a wide range of soils. Updates are also provided in terms of in situ state parameter, peak friction angle, and soil sensitivity. The correlations are evaluated using available laboratory and full-scale field test results. Many of the recommendations contained in this paper are focused on low to moderate risk projects where empirical interpretation tends to dominate. For projects where more advanced methods are more appropriate, the recommendations provided in this paper can be used as a screening to evaluate critical regions–zones where selective additional in situ testing and sampling maybe appropriate.

scholarly journals Geological and geotechnical investigations of Tapovan-Vishnugad Hydroelectric Project, Chamoli District, Uttarakhand, India

2006 ◽  
Vol 34 ◽  
pp. 1-16
Author(s):  
Ajay K. Naithani ◽  
K. S. Krishna Murthy
Keyword(s):  
Rock Type ◽  
Deformation Modulus ◽  
Friction Angle ◽  
Coarse Grained ◽  
Main Central Thrust ◽  
Hydroelectric Project ◽  
Geotechnical Investigations ◽  
Weak Zones ◽  
In Situ Deformation

The Tapovan- Vishnugad Hydroelectric Project is located in the Dhauliganga and Alaknanda valleys, where the Central Crystallines are composed mainly of medium- to high-grade metamorphics represented by augen gneisses, metabasics, fine­ grained quartz-mica gneisses, micaschists, quartzites, and coarse-grained garnet-biotite-kyanite gneisses. Towards the south, they are thrust over the Lesser Himalayan rocks of the Garhwal Group along the Main Central Thrust. The study aims at modelling the effects of geological structures for determining the potentially fractured or weak zones in underground excavations. For this purpose, Q and RMR values are obtained for each rock type. The in situ deformation modulus, cohesion, and friction angle are estimated to design support systems in unstable zones.

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

Patterns in diversity and composition of the microbenthos of subarctic intertidal beaches with different morphodynamics

2020 ◽  
Vol 648 ◽  
pp. 19-38
Author(s):  
AI Azovsky ◽  
YA Mazei ◽  
MA Saburova ◽  
PV Sapozhnikov
Keyword(s):  
Species Abundance ◽  
Abundance Ratio ◽  
Wave Action ◽  
Coarse Grained ◽  
Sediment Properties ◽  
Β Diversity ◽  
Α Diversity ◽  
Wide Range ◽  
Similar Mode ◽  
Abundance And Diversity

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

Site specific agricultural soil management with the use of new technologies

2013 ◽  
Vol 16 (1) ◽  
pp. 59-67
Keyword(s):  
New Technologies ◽  
Digital Interface ◽  
Appropriate Treatment ◽  
Wide Range ◽  
Soil Variation ◽  
Soil Information ◽  
Remote Sensing Techniques ◽  
Agricultural Areas

<p>The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty of these studies is that local agronomists have immediate access to a wide range of soil information by clicking on a field parcel shown in this digital interface and, therefore, can suggest an appropriate treatment (e.g. liming, manure incorporation, desalination, application of proper type and quantity of fertilizer) depending on the field conditions and cultivated crops. A specific case study is presented in the current work with regards to the construction of the digitized Soil Map of the regional unit of Kastoria. The potential of this map can easily be realized by the fact that the mapping of the physicochemical properties of the soils in this region provided delineation zones for differential fertilization management. An experiment was also conducted using remote sensing techniques for the enhancement of the fertilization advisory software database, which is a component of the digitized map, and the optimization of nitrogen management in agricultural areas.</p>

Indium Bromide-catalyzed Unprecedented Hydrogenolysis: A Novel One-Pot Synthesis of Per-O-Acetylated β-carboxymethyl O and S-glycosides

2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik
Keyword(s):  
Asymmetric Synthesis ◽  
Chiral Auxiliary ◽  
Bioactive Molecules ◽  
One Pot ◽  
Enantiomerically Pure ◽  
Stereoselective Glycosylation ◽  
One Pot Synthesis ◽  
Wide Range

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.

scholarly journals Predictive modelling of soils’ hydraulic conductivity using artificial neural network and multiple linear regression

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Charles Gbenga Williams ◽  
Oluwapelumi O. Ojuri
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Hydraulic Conductivity ◽  
Linear Regression ◽  
Multiple Linear Regression ◽  
Coarse Grained ◽  
Soil Types ◽  
Wide Range ◽  
Artificial Neural ◽  
Input Variables

AbstractAs a result of heterogeneity nature of soils and variation in its hydraulic conductivity over several orders of magnitude for various soil types from fine-grained to coarse-grained soils, predictive methods to estimate hydraulic conductivity of soils from properties considered more easily obtainable have now been given an appropriate consideration. This study evaluates the performance of artificial neural network (ANN) being one of the popular computational intelligence techniques in predicting hydraulic conductivity of wide range of soil types and compared with the traditional multiple linear regression (MLR). ANN and MLR models were developed using six input variables. Results revealed that only three input variables were statistically significant in MLR model development. Performance evaluations of the developed models using determination coefficient and mean square error show that the prediction capability of ANN is far better than MLR. In addition, comparative study with available existing models shows that the developed ANN and MLR in this study performed relatively better.

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