Grain size characteristics of surface aeolian sands in the downwind margin of modern Mu Us Sandland

2020 ◽  
Author(s):  
Zhongyuan Wang ◽  
Yongqiu Wu
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Fraction ◽  
Boundary Line ◽  
Aeolian Sand ◽  
Different Grain Size ◽  
Morphologic Type ◽  
Aeolian Sands

<p>Desert (sandland) margin is the transition region from inner aeolian landforms  to other landforms outside, while it remains as an ambiguous conception in previous researches. Accurately delineating its boundary line and realizing the characteristics of the particle size distribution of surface aeolian sands in margin area can help us understand the formation of modern boundary of desert (sandland). In this research, the criteria of identification of the boundary were proposed and the boundary line was extracted quantitative. Then systematic analyses of grain size of aeolian sand in margin were conducted. Together with the morphologic type, activity and the geomorphological location of collected dunes, the factors controlled the particle-size distributions had also been analyzed. The results reveal the following: (1) There is notable difference in grain size characteristics of aeolian sand between inside and outside of Mu Us sandland. The outside samples are finer than inside. Additionally, the aeolian sand covering on loess is always more poorly sorted and with different grain size fraction composition. (2) The controlling factors on particle size distribution are different in different downwind margins. In southwest margin, the grain size characteristics of aeolian sand are influenced by time and degree of stabilization of sampled dune and locally topographic relief; From the estuary of Lu River to Yuxi River, sediment transport by wind is affected by topographic obstacles including both valley and loess gully. Meanwhile, the small dunefields in Loess Plateau outside of Mu Us sandland may originate from a local alluvial source; In northeast downwind margin, the grain size characteristics of aeolian sand covering on loess are determined by regional gully erosion after its deposition.</p>

scholarly journals FIT Method for Calculating Soil Particle Size Distribution from Particle Density and Settling Time Data

2006 ◽  
Vol 55 (1) ◽  
pp. 295-304 ◽  
Author(s):  
Balázs Kovács ◽  
I. Czinkota ◽  
L. Tolner ◽  
Gy. Czinkota
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Density ◽  
Size Fraction ◽  
Soil Particle ◽  
Disperse Systems ◽  
Settling Speed ◽  
Grain Size Fractions

Particle size distribution (PSD) is one of the most important fundamental physical properties of soils, as it determines their physical, chemical, mechanical, geotechnical, moreover environmental behaviour. Although the measurement of PSD with different techniques is commonly performed in soil laboratories, their automation and continuous PSD curve generation have not been solved yet.  However, there are some physical principles, various sensors and different data storing methods for measuring the density-time function. In the present paper a possible solution is introduced for the measurement of the soil particle density database as a function of settling time. The equipment used for this purpose is an areometer that is widely used e.g. for determining the sugar content of must, or the alcohol content of distilled spirits, etc. The device is equipped with patent pending capacitive sensors on the neck of the areometer. It measures the changes in the water levels nearby the neck of the areometer in 1 μm units with <10 μm accuracy. The typical water level changes are 3-5 cm, which makes possible a very accurate determination of particle density changes due to settling in particle size analysis. The measured signals are stored in the equipment's memory and can be downloaded to the controller computer via a modified USB port. Data evaluation can be carried out online or later. The large number of measured data points led to the introduction of a new evaluation method, the Method of FInite Tangents or shortly the “FIT Method”. The dispersed soil particle system is considered as the aggregation of many mono-disperse systems. From this it follows that the measured density-time function can be divided into grain size fractions with tangent lines drawn to finite, but optional points. These tangent lines are suitable for calculating the settling speed of a given fraction, as the changing speed of density is equal to the multiplication of settling speed and mass of the given grain size fraction. The settling speed of all fractions is calculable by using the Stokes law, so the mass of all of the floating fraction can be calculated. Because the soil suspension is a poly-disperse system, the measured density decrease can be considered as an integration of finite mono-disperse systems. From this, it follows that it can be interpreted as the sum of linear density vs. time functions. If the mass of each grain size fraction is known, the particle size distribution is calculable. The method is relatively easily programmed and the intervals of grain size fractions are freely adjustable, so with this program almost all types of particle size distribution are calculable, not only those being uniform. Using the appropriate controller and evaluation program, soil particle size distribution can be calculated immediately after downloading the measured data. This technique does not need more sample preparation than past methods. The automated reading lessens the manpower required for performing the measurement - which also reduces human error sources - and provides very detailed PSD data that has advantages, among others, like revealing multi-modality in the particle-size distribution.

scholarly journals Laser Diffraction as An Innovative Alternative to Standard Pipette Method for Determination of Soil Texture Classes in Central Europe

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1232
Author(s):  
Dušan Igaz ◽  
Elena Aydin ◽  
Miroslava Šinkovičová ◽  
Vladimír Šimanský ◽  
Andrej Tall ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Soil Texture ◽  
Polynomial Regression ◽  
Texture Classification ◽  
Size Fraction ◽  
Laser Diffraction ◽  
Classification Systems ◽  
Particle Size Fraction

The paper presents the comparison of soil particle size distribution determined by standard pipette method and laser diffraction. Based on the obtained results (542 soil samples from 271 sites located in the Nitra, Váh and Hron River basins), regression models were calculated to convert the results of the particle size distribution by laser diffraction to pipette method. Considering one of the most common soil texture classification systems used in Slovakia (according to Novák), the emphasis was placed on the determination accuracy of particle size fraction <0.01 mm. Analysette22 MicroTec plus and Mastersizer2000 devices were used for laser diffraction. Polynomial regression model resulted in the best approximation of measurements by laser diffraction to values obtained by pipette method. In the case of particle size fraction <0.01 mm, the differences between the measured values by pipette method and both laser analyzers ranged in average from 3% up to 9% and from 2% up to 11% in the case of Analysette22 and Mastersizer2000, respectively. After correction, the differences decreased to average 3.28% (Analysette22) and 2.24% (Mastersizer2000) in comparison with pipette method. After recalculation of the data, laser diffraction can be used alongside the sedimentation methods.

scholarly journals Particle Size Distribution of the Coal Bottom Ash from the Large Combustion Plant

2015 ◽  
Vol 13 ◽  
pp. 210-215 ◽  
Author(s):  
Olimpia Ghermec ◽  
Ionela Gabriela Bucse ◽  
Mariana Ciobanu
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Bottom Ash ◽  
Size Fraction ◽  
Steam Boiler ◽  
Major Fraction ◽  
Coal Bottom Ash ◽  
Particle Size Analyzer ◽  
Reduce Emissions

Human existence is dependent on the consumption of electricity and of thermal energy. One of the environmental problems is represented by the particulate matter with the diameter of less than 2.5 mm derived from combustion of coal. In order to find solutions to reduce emissions at source, the particle size distribution of the coal bottom ash after removing it from the steam boiler of the large combustion plant from Romag Halanga in Drobeta Turnu – Severin area was determined. Dry particle size distribution shows that the major fraction is one that has a particle size of 125 μm. Particle size distribution in the smallest size fraction was performed with laser diffraction particle size analyzer Brookhaven 90 Plus Nanoparticle Size Analyzer. Particle size distribution shows that in the composition of the coal bottom ash were found particles with nanometric dimensions.

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

An alternative method for determining particle-size distribution of forest road aggregate and soil with large-sized particles

2014 ◽  
Vol 44 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Hakjun Rhee ◽  
Randy B. Foltz ◽  
James L. Fridley ◽  
Finn Krogstad ◽  
Deborah S. Page-Dumroese
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Fraction ◽  
Forest Road ◽  
State Highway ◽  
American Society ◽  
Northern Idaho ◽  
Aggregate Material ◽  
Laboratory Time

Measurement of particle-size distribution (PSD) of soil with large-sized particles (e.g., 25.4 mm diameter) requires a large sample and numerous particle-size analyses (PSAs). A new method is needed that would reduce time, effort, and cost for PSAs of the soil and aggregate material with large-sized particles. We evaluated a nested method for sampling and PSA by comparing it with the methods that follow the American Association of State Highway and Transportation Officials (AASHTO) standard T88-00 and the American Society for Testing and Materials (ASTM) standard D422-63. Using 33 forest road aggregate samples from the Clearwater National Forest in northern Idaho, the nested method required much less laboratory time and effort and resulted in similar PSA values, except for the 0.149 mm (No. 100) sieve, where the smallest particle-size fraction (PSF) values (1.30% and 1.39%) were observed. The nested method shows great potential for determining PSDs of the soil and aggregate material with large-sized particles and should be tested on other forest soils and road aggregates. The nested sampling and analysis method allows for the same number of samples to be collected but requires less laboratory time, making it more efficient and economical for testing the soil and aggregate material with large-sized particles such as forest road aggregate.

scholarly journals Grain Size Characteristics of Sediments Found in Typical Landscapes in the Playa of Ebinur Lake, Arid Central Asia

Land ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1132
Author(s):  
Na Wu ◽  
Yongxiao Ge ◽  
Jilili Abuduwaili
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Wind Erosion ◽  
Fine Sand ◽  
Haloxylon Ammodendron ◽  
Ebinur Lake ◽  
Cumulative Curve ◽  
Desert Zone

A playa usually refers to a salt desert landscape mainly composed of loose and fine lacustrine sediments. Severe wind erosion on a playa causes the playa to become a source of dust and salt dust and poses a threat to vast areas downwind. Currently, little is known about the impact of wind erosion on the particle size distribution of sediments in different landscapes in the playa. In the present study, six dominant different landscapes in a natural state with the same sedimentary environment in the playa of Ebinur Lake were selected to provide insights into the different characteristics of particle size distribution under the effect of long-term wind erosion. The results reveal that the grain-size composition clearly differed among different landscapes. All samples had a common dominant size group consisting of very fine sand and sand. The very fine sand and sand content of Haloxylon ammodendron desert zone (LS5) was the lowest, while the clay and silt content was the highest at both depths among the six landscapes. The lowest clay and silt fraction and highest sand fraction appeared in the herbal desert zone (LS3) at both depths. Almost all of the sediment samples were of a bimodal distribution mode, with significant differences. The cumulative curve showed a similar S-shape, while the probability cumulative curve showed an inverted S-shape with three subpopulations of granularity characteristics. The smallest mean particle diameter appeared in LS5. The majority of the sediments were moderately to poorly sorted. The mean particle size of the sediments from the six landscapes was significantly different (p < 0.05), while no significant difference was observed among the other three parameters. Generally, it can be inferred that LS5 can reduce wind speed effectively, probably due to the smaller leaves and dense branches of Haloxylon ammodendron, which results in a high level of coverage. The results of the present study will have some implications for the grain size characteristics for changes in intensity in regional wind erosion environment and will also have some basis for wind erosion prevention and control in the playa of Ebinur Lake.

scholarly journals Comparison of pipette method and state of the art analytical techniques to determine granulometric properties of sediments and soils

2020 ◽  
Vol 69 (1) ◽  
pp. 27-39
Author(s):  
Fruzsina Gresina
Keyword(s):  
Earth Sciences ◽  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Measurement Techniques ◽  
Industrial Applications ◽  
Laser Diffraction ◽  
Cement Industry ◽  
Coarse Grained

The determination of particle size distribution is a crucial issue in various fields of earth sciences (e.g., Quaternary research, sedimentology, stratigraphy, structural geology, volcanology), environmental sciences as well as diverse industrial applications (e.g., pharmaceuticals, cement industry). New measurement techniques developed as a result of industrial demands have also gained ground in environmental and Earth sciences research. The new techniques (especially laser diffraction) have enabled the particle characterisation in the broader size-range with a more detailed resolution. Still, they have to be compared with data obtained by classical methods. In light of the above, the primary aim of our research is to examine the methods of particle size determination critically. Excessive oversimplifications of particle size analyses routinely have used in paleo-environmental and paleo-climatological reconstructions, and other sedimentary studies, as well as insufficient knowledge of the background of the applied methods, distort the interpretation of the results. Over the past four decades, laser diffraction particle size analysers have proven to be practical tools of particle size characterisation. However, the shape of the natural sediment and soil particles are irregular and, therefore, affects the particle size distribution results obtained by different methods. The results of the traditional pipette method differed from laser diffraction results. The presence or absence of the pretreatments did control the differences between the two techniques. The results of Fraunhofer optical method were significantly different from Mie theory because it can detect much lower volume percentages of finer particles. Grain size results of coarse-grained samples measured by different laser diffraction devices were more comparable than the results of more clayey samples. The ratios of different sizes were changed due to the hydrochloric acid and hydrogen peroxide pretreatments. The comparison of different techniques is necessary to revaluate standards in grain size measurements which can enable the shift from conventional methods to more productive and reproducible methods. Still, light scattering techniques have not yet been able to displace classical methods in Earth sciences completely, in contrast to industrial applications.

scholarly journals Comparison of laser diffraction method and hydrometer method for soil particle size distribution analysis

2021 ◽  
Vol 24 (1) ◽  
pp. 49-55
Author(s):  
Kateřina Sedláčková ◽  
Lenka Ševelová
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Distribution Curve ◽  
Diffraction Method ◽  
Laser Diffraction ◽  
Soil Science ◽  
Distribution Analysis

Abstract The article aims to present a comparative study of two methods used to determine the particle size distribution of fine and medium coarse soils. These methods are used to determine the grain size distribution curve in practice; however, for different purposes. The classical sedimentation method, based on the Stoke’s sedimentation law (hydrometer, areometric, the Casagrande’s method), standardized for a geotechnical classification of soils was compared with the laser diffraction method on the Mastersizer 3,000 analyser used for soil science purposes. The first comparison on nine samples showed significant differences, especially for larger fractions above 0.01 mm. All measured values of falls from laser diffraction analysis (LDA) showed higher values of all analysed fractions. It was also interesting to follow the trend between the tests for the preparation of conversion factors. The analysis also outlined the direction for further comparison. For the geotechnical use of the LDA, it will be necessary to take into account the sample preparation and processing before analysis.

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