scholarly journals Laboratory and field investigations in granular soils to correlate relative density, relative compaction and grain size

2020 ◽  
Vol 62 (2) ◽  
Author(s):  
H Mujtaba ◽  
K Farooq ◽  
N Sivakugan ◽  
B M Das
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Granular Soils ◽  
Field Investigations ◽  
Relative Compaction

Sedimentological and Biological Changes Associated with the Construction of the Oil Terminal of Antifer, France

1984 ◽  
Vol 16 (3-4) ◽  
pp. 399-406
Author(s):  
Y Monbet
Keyword(s):  
Grain Size ◽  
Environmental Changes ◽  
Biological Effects ◽  
Standing Stock ◽  
Natural Populations ◽  
Benthic Fauna ◽  
Field Investigations ◽  
Mean Grain Size ◽  
To Receive ◽  
Principal Species

A study was conducted to gain insight on actual sedimentological and biological effects associated with the construction of an oil Terminal designed to receive 500 000 d.w.t. tankers. Field investigations and subsequent laboratory analyses were organized to evaluate the nature and magnitude of environmental changes on benthic macrofauna, three years after the end of the construction. Sediments were found to decrease dramatically in medium grain size in area sheltered by the newly built breakwater. Increase of percentage of silt and clays (90 % against 20 %) was observed leeward of the jetty. The benthic fauna showed significant modifications. Although the same community (Pectinaria kareni Abra alba) recolonized the bottom after the dredging of up to 30 × 106 m3 of sediments, increase in abundance occured. Biomass remained at a constant level and decrease of diversity was observed. Considering the rate of siltation, and assuming a constant siltation rate equal to the rate observed from 1975 to 1978, a simple regressive model relating biomass to mean grain size of sediments has been developped. This model allowed the prediction of biomass and production of the two principal species for the period 1978 – 1981. Continuous siltation within the harbor leads to a maximum of biomass from years after the end of the construction, followed by a decrease of standing stock. This process may be explained by the respective tolerance of the two principal species to increase silt contant and also probably by the accumulation of organic matter which may impede the development of natural populations.

scholarly journals Comparison of Different Empirical Correlations to Estimate Permeability Coefficient of Quaternary Danube Soils

2018 ◽  
Author(s):  
Miklós Pap ◽  
András Mahler
Keyword(s):  
Grain Size ◽  
Permeability Coefficient ◽  
Carpathian Basin ◽  
Laboratory Measurement ◽  
Granular Soils ◽  
Empirical Correlations ◽  
Soil Parameter ◽  
Measurement Results

Permeability coefficient is the most significant soil parameter in seepage calculations. It has been recognized that permeability of granular soils is strongly related to the grain size, thus numerous empirical correlations have been developed to estimate permeability using its grain size characteristics. In this study the empirical correlations proposed by Hazen (1911), Carrier (2003) and Chapuis (2004) are evaluated and compared to laboratory measurement results. Quaternary Danube soils are very typical in the Carpathian basin, thus their permeability is an important question in many geotechnical applications.

Effect of Gel-Calcination on Piezoelectric Property in (1-x)BiScO3-xPbTiO3 Ferroelectrics

2010 ◽  
Vol 434-435 ◽  
pp. 335-339
Author(s):  
Han Wang ◽  
Xiao Hui Wang ◽  
Shao Peng Zhang ◽  
Long Tu Li ◽  
Zhao Hui Huang
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Piezoelectric Property ◽  
Relative Density ◽  
Heating Rate ◽  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Processing Condition ◽  
Powder Particle Size ◽  
Different Temperatures

In this paper, the effect of gel-calcination on piezoelectric property in (1-x) BiScO3-xPbTiO3 with the composition of x=0.635 is investigated. According to previous work, the heating rate of 200°C/h and holding for 210min having been taken as the basic processing condition. The BSPT powders were obtained from the same sol solution but calcined at different temperatures, and then the powders were used to prepare BSPT ceramics. The result shows that for the bulk ceramics with higher relative density ( higher than 95%), with the increasing calcining temperature of the gel (from 420°C to 500°C), the piezoelectric coefficient d33 of ceramic specimens first increases to maximum of 636pC/N at 450°C, then shows a fluctuation. In this work how the powder activity and the grain size affect (which was leaded by powder particle size) piezoelectric properties of BSPT ceramics are discussed.

The Effect of Holding Time on the Mechanical Properties and Microstructure of Sintered NbC Composite

2010 ◽  
Vol 123-125 ◽  
pp. 803-806
Author(s):  
Duck Soo Kang ◽  
Kee Do Woo ◽  
Sang Hyuk Kim ◽  
In Jin Shon ◽  
Ji Young Kim ◽  
...  
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
High Frequency ◽  
Holding Time ◽  
Full Width ◽  
Petch Relation ◽  
Sintering Time ◽  
Rapid Sintering ◽  
Sintering Method ◽  
High Frequency Induction

High frequency induction heated sintering (HFIHS) method is one of the rapid sintering methods. The advantage of rapid sintering method is that grain growth can be prevented during sintering at high temperature. Refinement of grains was known to increase the yield and flow stresses of crystals. The relation between the yield stress and the grain size is known as Hall-Petch relation. NbC-10vol.%Co, Ni and Fe composites were fabricated by HFIHS at 1060°C for 0 and 3 min as holding times under a pressure of 80MPa.The relative density of NbC-10vol.%Co, Ni and Fe composites which were sintered at 1060°C for 0min as holding time under 80MPa were 91.90%, 91.26% and 91.26%, respectively. These composites are difficult to use industrial parts due to low relative density. The longer sintering time was conducted for increasing relative density in this study. Nano-sized specimens, which were calculated grain size by full-width at half maximum (FWHM), can be obtained by HFIHS. The value of hardness and fracture toughness was investigated using 20kgf load Vickers indenter.

Sintering and Mechanical Properties of Alumina Ceramics Prepared by Nanosize Alumina

2007 ◽  
Vol 544-545 ◽  
pp. 821-824
Author(s):  
Indra ◽  
S.W. Oh ◽  
Hee Joon Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Relative Density ◽  
Mechanical Characteristics ◽  
Indentation Test ◽  
Test System ◽  
Alumina Ceramics ◽  
New Materials ◽  
Size Dependent

This work examined the mechanical properties of alumina that can directly be enhanced by ratio of nano sized alumina powders additives to micro size alumina powders (n/m ratio). These new materials have mechanical properties that are strongly grain size dependent and often significantly different from those of their coarser grained counter parts. The mechanical characteristics of samples were observed by using the indentation test system. This data shows that the relative density for the sample is increased with increasing Meyer hardness.

Similarity of internal stability criteria for granular soils

1992 ◽  
Vol 29 (4) ◽  
pp. 711-713 ◽  
Author(s):  
Robert P. Chapuis
Keyword(s):  
Grain Size ◽  
Groundwater Flow ◽  
Distribution Curve ◽  
Fine Particles ◽  
Frost Damage ◽  
Granular Soils ◽  
Internal Stability ◽  
Stability Criteria ◽  
Mathematical Expressions ◽  
Internal Instability

Internal instability produces segregation in fine particles, modifies drainage properties, and increases pore pressures, capillary retention, and possible frost damage. Three criteria are commonly used to assess the internal instability of granular soils. It is shown here that they can take similar mathematical expressions where the secant slope of the grain-size distribution curve indicates the risk of internal instability. Key words : suffossion, groundwater flow, gradation.

Enhanced Densification and Grain-Size Refinement in Cation-Doped Tetragonal Zirconia

2010 ◽  
Vol 62 ◽  
pp. 227-231
Author(s):  
Keijiro Hiraga ◽  
Hidehiro Yoshida ◽  
Koji Morita ◽  
Byung Nam Kim
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Grain Growth ◽  
Sintering Temperature ◽  
Initial Density ◽  
Tetragonal Zirconia ◽  
The Other ◽  
Size Refinement ◽  
Grain Sizes ◽  
Materials Used

In tetragonal zirconia, possibility is investigated of densification with finer grain sizes under the combination of doping and sintering in air. The materials used are CIP'ed compacts of 3-mol%-yttria-stabilized tetragonal zirconia (3Y-TZP) doped with a small amount of cations. For a given sintering temperature and initial density of the compacts, while the doped cations enhances densification in the latest stage of sintering, the effect is different in grain growth during densification: a doped cation tended to enhance grain growth, whereas the other cations tended to suppress grain growth. As a result, the doping of the latter cations brings about a grain size finer than that of the undoped 3Y-TZP for a given relative density.

scholarly journals Numerical Simulation and Experimental Verification of Dry Pressed MgTiO3 Ceramic Body during Pressureless Sintering

2021 ◽  
Author(s):  
Jiang Wang ◽  
Yu Ni ◽  
Kai Liu ◽  
Yanying Du ◽  
Wei Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Relative Density ◽  
Ceramic Body ◽  
Simulation Method ◽  
Shrinkage Rate ◽  
Pressureless Sintering ◽  
Numerical Simulation Method ◽  
Average Grain Size ◽  
Simulation Results

Abstract To clarify the densification law of dry pressed MgTiO3 ceramic body during pressureless sintering, SOVS model modified with creep characteristics was embedded into finite element software Abaqus. The selected model can effectively express the grain boundary characteristics and densification mechanism. The change law of relative density, shrinkage rate, sintering stress and grain size of MgTiO3 cylindrical specimens were investigated by the above numerical simulation method. It showed that the average relative density of ceramic body rose from 60% to 97% and the shrinkage rate resepectively reached 17.28% and 11.99% in axial and radial direction. The average grain size increased from 1μm to 6 μm. In order to verify the accuracy of the simulation results, corresponding sintering experiments on cylindrical specimens were carried out to obtain actual sintering densities and shrinkage rates. It showed that the errors of relative density and shrinkage is below 5% and 2%. Grain growth trend was also basically consistent with the simulation results. After that, the above numerical simulation method was applied into the prediction of fabricating MgTiO3 filter with complex structure. Therefore, the present work provided a reliable numerical simulation method to predict the densification behavior of MgTiO3 ceramics during the pressureless sintering process, which was helpful to design and fabricate microwave dielectric products.

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