scholarly journals Mesoscale geomorphic change on barrier estuarine regime at the tropical coast of Chandipur, India: Evidence from assessment of grain-size distribution

2022 ◽  
Author(s):  
Koushik Saha ◽  
SUBHAJIT SINHA
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Compositional Data ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Compositional Data Analysis ◽  
Multivariate Statistical ◽  
Marsh Sediment ◽  
Log Normal

Abstract It is crucial for policy makers and environmental managers to determine the future dynamics of coastal wetlands, especially the existence of their response, disruption, and recovery regimes. Reconstruction of meso-scale evolution in coastal ecosystems can help to adapt coastal resource management techniques to the natural scales of system activity, thereby encouraging true biodiversity. This research provides an overview of decadal (mesoscale) geomorphic transition by high-resolution grain size analysis of a sediment deposit from a barrier estuary regime on the Chandipur coast, India. Coastal marshland’s grain size distribution (GSD) has generally been analyzed using End Member Mixing Models (EMMA) and Probability Density Function (PDF) methods (e.g. log-normal, log skew-Laplace). Although these techniques do not consider the compositional nature of the records, which can undermine the outcomes of the interpretation of sedimentary deposits. The approach to reliable granulometric analysis of lithostratigraphic sequences aims at establishing direct links between fluid dynamics and subsequent shifts in the texture of sediments. In this study, GSD analysis of marsh sediment is represented by compositional data analysis (CoDa) and a multivariate statistical framework. Barrier estuary evolution, presented by time lapses of satellite maps coupled with grain size and carbon content of marsh sediment, primarily reflects the evolving hydrodynamics of the back barrier area. These findings will provide a statistically robust analysis of the depositional system in coastal marshland. Multiannual environmental variations in the back barrier configuration illustrate the importance of this applied approach with respect to bridging the basis of estuarine evolution and process information.

scholarly journals Reconsideration at Field Scale of the Relationship between Hydraulic Conductivity and Porosity: The Case of a Sandy Aquifer in South Italy

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Carmine Fallico
Keyword(s):  
Grain Size ◽  
Hydraulic Conductivity ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Effective Porosity ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Strict Sense ◽  
Field Scale

To describe flow or transport phenomena in porous media, relations between aquifer hydraulic conductivity and effective porosity can prove useful, avoiding the need to perform expensive and time consuming measurements. The practical applications generally require the determination of this parameter at field scale, while most of the empirical and semiempirical formulas, based on grain size analysis and allowing determination of the hydraulic conductivity from the porosity, are related to the laboratory scale and thus are not representative of the aquifer volumes to which one refers. Therefore, following the grain size distribution methodology, a new experimental relation between hydraulic conductivity and effective porosity, representative of aquifer volumes at field scale, is given for a confined aquifer. The experimental values used to determine this law were obtained for both parameters using only field measurements methods. The experimental results found, also if in the strict sense valid only for the investigated aquifer, can give useful suggestions for other alluvial aquifers with analogous characteristics of grain-size distribution. Limited to the investigated range, a useful comparison with the best known empirical formulas based on grain size analysis was carried out. The experimental data allowed also investigation of the existence of a scaling behaviour for both parameters considered.

scholarly journals Comparative Grain-Size Measurements for Validating Sampling and Pretreatment Techniques in Terms of Solifluction Landforms, Southern Carpathians, Romania

2015 ◽  
Vol 8 (1-2) ◽  
pp. 39-47
Author(s):  
Raul David Serban ◽  
György Sipos ◽  
Mihaela Popescu ◽  
Petru Urdea ◽  
Alexandru Onaca ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Diffraction Method ◽  
Sampling Procedure ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Important Indicator ◽  
Parallel Measurements ◽  
Southern Carpathians

AbstractGrain-size distribution has become in the last years an important indicator in the analysis of periglacial processes and landforms. However, as they exhibit a complex sedimentology, careful sampling is required to draw meaningful conclusions. The aim of the present study was therefore to validate the sampling procedure carried out on solifluction forms and to evaluate the effect of sampling pretreatment during grain size analysis. A comparison between multiple measurements of grain size distribution using the laser diffraction method (LDM) was performed on 54 sediment samples collected from different solifluction landforms at different depths in the alpine area of the Southern Carpathians. The results of parallel measurements were compared using textural and statistical indicators. The received distributions reinforced the properness of field sampling procedure in most of the cases. The results of textural classification and fractional composition showed a high consistency between the two parallel measurements made on untreated and pretreated samples. An overall fining as a matter of etching was identified. Relative deviation increased and correlation decreased as pretreatment advanced. HCl etching resulted a greater deviation and variability in case of the sand fraction, H2O2rather affected the silt fraction. The greatest deviations were experienced in case of landforms developed on crystalline limestone. Pretreatment of samples introduced a major uncertainty to further comparison and interpretation. Thus, multiple LD measurements on a representative group of samples from the entire sample set were suggested before the geomorphological or environmental interpretation of results to decrease the uncertainties and to validate the processes

scholarly journals Investigation of Particle Size Distribution for Fine-Grained Soil Using a Grain Size Analysis Equipment Automated by X-ray Method

2000 ◽  
Vol 40 (2) ◽  
pp. 127-133
Author(s):  
Yukio Furukawa ◽  
Tatsushi Fujita ◽  
Tadayuki Kunihiro ◽  
Hisashi Tsuchiya ◽  
Yukio Saito
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Ray Method ◽  
X Ray ◽  
Fine Grained ◽  
Fine Grained Soil

scholarly journals The validity of laser diffraction system to reproduce hydrometer results for grain size analysis in geotechnical applications

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245452
Author(s):  
Hamzah M. Beakawi Al-Hashemi ◽  
Omar S. Baghabra Al-Amoudi ◽  
Zain H. Yamani ◽  
Yassir M. Mustafa ◽  
Habib-ur-Rehman Ahmed
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Image Analysis ◽  
Size Distribution ◽  
Digital Image ◽  
Digital Image Analysis ◽  
Laser Diffraction ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Distribution Method

The grain size analysis plays a significant role in any geotechnical study. The grain size analysis, by means of sieving, is usually used for coarse material of particle size > 75 μm. For the fine material; the sedimentation methods are frequently adopted (e.g., hydrometers). Other methods also exist such as electron microscopy, digital image analysis and laser diffraction. The fine geomaterials commonly undergo agglomeration which makes the recognition of individual grain size using digital image analysis or electron microscopy challenging. To facilitate and enhance the grain-size analysis, this study was conducted using the Laser Diffraction System (LDS). Seven samples with different nature (composition and texture) and sources were analyzed by hydrometer and LDS. For LDS, various factors were studied such as air pressure, sonication, dilution, refractive index, and distribution method (volume or number). The results were compared qualitatively and quantitatively based on soil classification systems, fractal dimensions, and other parameters. Furthermore, this study provided a novel criterion to determine which LDS distribution method (volume or number) is to be used depending on the Liquid Limit. A combined sieve-LDS system is recommended to obtain the entire grain size distribution. It is concluded that the LDS is a viable technique that can replace the time-consuming hydrometer method to assess the grain-size distribution.

scholarly journals Modern methods of grain size distribution of soils

2013 ◽  
pp. 302-308
Author(s):  
Volodymyr Radzii
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Soil Mass ◽  
Particle Size Analysis ◽  
Soil Science ◽  
Size Analysis ◽  
Ecological Functions ◽  
Modern Methods

Grain size distribution of soil determines much of water and physical properties of the soil mass. However, it defines ecological functions and morphological memory of soils in the study of their genesis, evolution and use. This article describes the main methods of particle size analysis and suggests the modern methods used increasingly in the research in soil science, geology, chemical, pharmaceutical and other industries. Key words: particle size distribution of soil, sedimentograph, laser diffraction.

Deposition and Characterization of Polycrystalline Silicon Films on Glass for thin Film Solar Cells

1997 ◽  
Vol 467 ◽  
Author(s):  
R. B. Bergmann ◽  
J. Krinke ◽  
H. P. Strunk ◽  
J. H. Werner
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Solid Phase ◽  
Chemical Vapor ◽  
In Situ Monitoring ◽  
Random Nucleation ◽  
Amorphous Si ◽  
Log Normal ◽  
Polycrystalline Silicon Films

ABSTRACTWe deposit phosphorus-doped, amorphous Si by low pressure chemical vapor deposition and subsequently crystallize the films by furnace annealing at a temperature of 600°C. Optical in-situ monitoring allows one to control the crystallization process. Phosphorus doping leads to faster crystallization and a grain size enhancement with a maximum grain size of 15 μm. Using transmission electron microscopy we find a log-normal grain size distribution in our films. We demonstrate that this distribution not only arises from solid phase crystallization of amorphous Si but also from other crystallization processes based on random nucleation and growth. The log-normal grain size distribution seems to be a general feature of polycrystalline semiconductors.

VSA: a new fast size analysis technique for low sample weight based on Stokes' settling velocity

1980 ◽  
Vol 17 (2) ◽  
pp. 304-312 ◽  
Author(s):  
J. P. M. Syvitski ◽  
D. D. Swinbanks
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Continuous Distribution ◽  
Weight Percent ◽  
Size Analysis ◽  
Marginal Effect ◽  
Analysis Technique ◽  
Low Weight ◽  
A New Technique

A new technique, VSA, provides a rapid, accurate, and precise method of determining the grain-size distribution of low weight samples. Its name, VSA, stands for volume size analysis. The apparatus is inexpensive and the proposed system can analyze four samples simultaneously in 85 min when used down to 0.45 μm size. The results are provided in sedimentation diameters. A set of equations, which discretely define the increasing volume of a homogeneous sediment sample settling in an enclosed volume of water, is solved to adequately approximate the continuous distribution. The final distribution is in terms of weight percent when bulk densities of discrete settled volumes are calculated. This additional calculation has only a marginal effect on the grain-size distribution of samples having means greater than 3 μm.VSA was compared with the pipette method and found to produce "statistically identical" size distributions.

Formation of polycrystalline silicon with log-normal grain size distribution

1998 ◽  
Vol 123-124 ◽  
pp. 376-380 ◽  
Author(s):  
Ralf B. Bergmann ◽  
Frank G. Shi ◽  
Hans J. Queisser ◽  
Jörg Krinke
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Polycrystalline Silicon ◽  
Log Normal

Characterization of Atmosphere PM2.5 and Dustfall in Xining (China)

2013 ◽  
Vol 562-565 ◽  
pp. 1422-1427 ◽  
Author(s):  
Jun Tang ◽  
Fa Qin Dong ◽  
Qun Wei Dai ◽  
Yue Quan Deng
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Elemental Composition ◽  
Size Distribution ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Mineral Phase ◽  
Three Samples ◽  
Particle Size Analyzer

In this paper, mineral phase, elemental composition and size distribution were analysed by means of XRD, XRF and laser particle size analyzer respectively. According to the results of XRD, quartz, illite, calcite and albite were all found in three samples; Dolomite was found only in dustfall; Clinochlore was existed in both PM2.5 and soil. From the results of XRF, elemental compositon of three samples were focused on elemental Na, Si, Al, S, Ca, Fe, Mg, K. Based on the grain size analysis, the size distribution of dustfall mainly ranges from 1µm to 40µm.

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