Data Report: Fine-Fraction Grain-Size Distribution Data and Their Statistical Treatment and Relation to Processes, Site 1095 (ODP Leg 178, Western Antarctic Peninsula)

Sediment transport rate depends on bed composition, flow hydraulics and sediment supply. There is a paucity of information on bedload transport in River Osun. In this study, bedload in River Osun was estimated using grain size distribution data to predict channel migration and mitigate flooding. Grab sampler was used to collect sediment samples at the sampling point across the river designated as T1-T4. Sieve analysis was carried out in triplicate on sediment from sampling points using standard methods. Discharge and cross-sectional area were measured between December 2017 and December 2018 at sampling stations using standard methods. The seasonal and bedload were estimated using standards equations. The percentage of bed material particles above 5mm and less than or equal to 2mm were 50 and 22.49%, respectively. The average median grain (d50) size was 2.4mm. The discharge and cross-sectional area across River Osun ranged (0.53-17.46) m3/s and (3.83-47.46) m2. The seasonal suspended and bedload across the river were (206.43×103 kg/annum) and 2,538.77×103(kg/annum), respectively. The estimated sediment load of River Osun could be useful in determining the dredging period at any point across the river where deposition of sediment could be monitored.

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Variation of the Descriptive Grain Size Distribution Along Cores From the Sebkha of Sidi El Hani, Eastern Tunisia

10.4018/978-1-7998-9498-8.ch012 ◽

2022 ◽

pp. 197-214

Author(s):

Elhoucine Essefi ◽

Soumaya Hajji

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Method Of Moments ◽

Statistical Treatment ◽

Special Care ◽

Statistical Parameters ◽

Sedimentary Dynamics

In this chapter, cores were the object of descriptive classifications of the grain size distribution, which were meant to describe the grain size continuous variability within cores and to correlate between them. The statistical treatment of the crude data was done on the basis of two different methods (the method of moments statistics and the method of inclusive graphic statistics) to compute statistical parameters of the grain size distribution such as mean and median. The correlations between cores were done on the basis of sand/silt/clay percentages. Even though it has given special care to test different methods of studying the grain size distribution, this study has not deviated from its primary purpose of investigating the filling of the playa; correlations between different cores were meant to infer their sedimentary dynamics.

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Grain sorting effects on the formation of tidal sand waves

Journal of Fluid Mechanics ◽

10.1017/s0022112009006387 ◽

2009 ◽

Vol 629 ◽

pp. 311-342 ◽

Cited By ~ 23

Author(s):

TOMAS VAN OYEN ◽

PAOLO BLONDEAUX

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Fine Fraction ◽

Sand Wave ◽

Flat Bottom ◽

Sand Waves ◽

Sand Mixture ◽

Sea Bed ◽

The Stability

A model is developed to investigate the process which leads to the formation of sand waves in shallow tidal seas characterized by a heterogeneous sea bed composition. The main goal of the analysis is the evaluation of the effects that a graded sediment has on the formation of the bottom forms and the investigation of the sorting process induced by the growth of the bottom forms. The analysis is based on the study of the stability of the flat bed configuration, i.e. small amplitude perturbations are added to the flat bottom and a linear analysis of their time development is made. For an oscillatory tidal current dominated by one tidal constituent, the results show that the graded sediment can stabilize or destabilize the flat bottom configuration with respect to the uniform sediment case, depending on the standard deviation σ* of the grain size distribution and on the ratio between the horizontal tidal excursion and the water depth. For moderate values of , i.e. values just larger than the critical value for which the sediment is moved and sand waves appear, the presence of a sand mixture stabilizes the flat bed. On the other hand, for large values of , the mixture has a destabilizing effect. In both cases the effect that a sand mixture has on the stability of the flat bed configuration is relatively small. Moreover, for moderate values of , the fine fraction of the mixture tends to pile up at the crests of the bottom forms while the coarse fraction moves towards the troughs. For large values of , the grain size distribution depends on the value of σ*. The results are physically interpreted and provide a possible explanation of the apparently conflicting field observations of the grain size distribution along the sand wave profile, carried out in the North Sea.

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Analysis of indices and operation improvement conditions of JSC “Ural Steel” blast furnace shop

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2018-12-46-54 ◽

2018 ◽

pp. 46-54

Author(s):

D. R. Ganin ◽

V. G. Druzhkov ◽

A. A. Panychev ◽

A. Yu. Fuks

Keyword(s):

Grain Size ◽

Blast Furnace ◽

Chemical Composition ◽

Size Distribution ◽

Grain Size Distribution ◽

Iron Ore ◽

Fine Fraction ◽

Production Operation ◽

Blast Furnaces ◽

Furnace Technology

For elaborating of measures to improve the blast furnace technology, it is necessary to analyze production data related to blast furnaces operation. Estimation of technical level of blast furnace production in conditions of JSC “Ural Steel” was the aim of the study. Data on chemical composition of casted iron produced and burden materials quoted, as well as data on iron ore materials consumption, sinter grain-size distribution, pellets chemical composition and strength characteristics, coke mechanical strength and grain-size distribution. Results of analysis presented of production operation indices of Nos 1–4 blast furnaces within a five years period, the furnaces having net volumes 1007, 1033, 1513 and 2002 m3 correspondently. Periods of non-stable furnaces operation with long stops and repairs were excluded from the analyzed data. It was determined that iron and manganese oxide contents in the sinter are presented at lower level comparing with most of sintering plants of European Communities and Japan. Fine fraction less 5 mm content is considerably higher than the index for sinter, produced at other sintering plants of Russia, as well as of developed nations. Laboratory study and experimental-industrial tests at JSC “Ural Steel” confirm reasonability of the following mineral additives utilization in sintering process, delivered into the sintering burden by sludge: brown iron ore, bentonite clay, serpentinite-magnesites, that enables to increase suitable sinter yield, productivity of sintering machines, sinter impact strength. A necessity to optimize blast furnace slags chemical composition by relation SiO2/Al2O3 and CaO/MgO determined to improve scull formation conditions and elimination of coolers mass burning-through. To improve the technical and economic indices of JSC “Ural Steel blast furnaces operation some measures on the plant blast furnace technology modification proposed.

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Long-term coastal openness variation and its impact on sediment grain-size distribution: a case study from the Baltic Sea

Earth Surface Dynamics ◽

10.5194/esurf-4-773-2016 ◽

2016 ◽

Vol 4 (4) ◽

pp. 773-780 ◽

Cited By ~ 1

Author(s):

Wenxin Ning ◽

Jing Tang ◽

Helena L. Filipsson

Keyword(s):

Grain Size ◽

Baltic Sea ◽

Size Distribution ◽

Grain Size Distribution ◽

Temporal Dynamics ◽

Distribution Data ◽

Sand Content ◽

Sediment Grain Size ◽

Study Region

Abstract. We analysed the long-term variations in grain-size distribution in sediments from Gåsfjärden, a fjord-like inlet in the southwestern Baltic Sea, and explored potential drivers of the recorded changes in the sediment grain-size data. Over the last 5.4 thousand years (ky) in the study region, the relative sea level decreased 17 m, which was caused by isostatic land uplift. As a consequence, Gåsfjärden was transformed from an open coastal setting to a semi-closed inlet surrounded by numerous small islands on the seaward side. To quantitatively estimate the morphological changes in Gåsfjärden over the investigated time period and to further link the changes to the grain-size distribution data, a digital elevation model (DEM)-based openness index was calculated. The largest values of the openness indices were found between 5.4 and 4.4 cal ka BP, which indicates relatively high bottom water energy. During the same period, the highest sand content (∼  0.4 %) and silt / clay ratio ( ∼  0.3) in the sediment sequence were also recorded. After 4.4 cal ka BP, the average sand content was halved to ∼  0.2 % and the silt / clay ratio showed a significant decreasing trend over the last 4 ky. These changes were found to be associated with the gradual embayment of Gåsfjärden, as represented by the openness indices. The silt  /  clay ratios exhibited a delayed and relatively slower change compared with the sand content, which indicates different grain-size sediment responses to the changes in hydrodynamic energy. Our DEM-based coastal openness indices have proved to be a useful tool for interpreting the temporal dynamics of sedimentary grain size.

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Downstream evolution of grain size in extremely mobile post-earthquake debris flows, China

10.5194/egusphere-egu21-7389 ◽

2021 ◽

Author(s):

Erin L. Harvey ◽

Tristram C. Hales ◽

Daniel E. J. Hobley ◽

Xuanmei Fan ◽

Jie Liu ◽

...

Keyword(s):

Grain Size ◽

Debris Flow ◽

Size Distribution ◽

Grain Size Distribution ◽

Debris Flows ◽

Fine Fraction ◽

Excess Pore Pressure ◽

Extreme Rainfall Event ◽

2008 Wenchuan Earthquake ◽

Grain Sizes

Large, catchment transitioning debris flows are an important mechanism for transporting sediment from hillslopes into higher order channels. Extremely large flows can exceed volumes of 109 m3, however even flows with volumes of&#160; ~103 m3 can lead to fatalities and extensive damage. Few processes transport a wider range of grain sizes than debris flows, which can transport grains from clays to 10 m boulders. While the structure of debris flows can often be inferred by their deposits, the range of grain sizes presents a challenge for their interpretation. Debris flow grain size distributions can be used to constrain debris flow runout due to their effect on excess pore pressure dissipation. Currently, there is limited data available for the entire grain size distribution of debris flow deposits in the field.We constrained the entire grain size distribution for two extremely large (>1 km in length) post-earthquake debris flows in Sichuan Province, China. These debris flows were triggered in August 2019 after an extreme rainfall event occurred close to the epicentre of the 2008 Wenchuan earthquake. We sampled the debris flows in November 2019 at intervals of 200 m and 500 m, respectively. At each site, we used a combination of field and laboratory sieving to obtain the coarse and fine fraction for both the surface and subsurface. We dug 1 m x 1 m x 0.5 m pits, excavating each layer at 10 cm depth increments. We sieved these increments into five size fractions in the field, including < 1 cm. We sieved 1 kg of the <1 cm fraction in the laboratory to estimate the distribution of the finest grains. The coarse surface fraction was then independently constrained using photogrammetry. Preliminary results for one debris flow show that the distribution of fine grains (~<4 mm) is consistent both laterally and vertically across the runout. This suggests that the processes occurring vertically and laterally during deposition result in the consistent distribution of fines.

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Grain size distribution of waste rock masses of Kuzbass coal strip mines

Mining science and technology ◽

10.17073/2500-0632-2021-4-259-266 ◽

2021 ◽

Vol 6 (4) ◽

pp. 259-266

Author(s):

S. O. Markov ◽

E. V. Murko ◽

F. S. Nepsha

Keyword(s):

Grain Size ◽

Rock Mass ◽

Size Distribution ◽

Grain Size Distribution ◽

Fine Fraction ◽

Waste Rock ◽

Height Distribution ◽

Rock Masses ◽

Lump Size ◽

Natural Rock

Grain size distribution as a structural characteristic of waste rock and bulk masses in the course of mining and construction works acquires quantitative values in the process of rock blasting and hauling of rock mass. Such physical-mechanical and structural-textural parameters of a rock mass, as the ultimate strength of rocks and rock mass, fracturing, diameter of the natural rock jointing, have a significant impact on the blasted rock mass grain size distribution. On the other hand, such characteristics as stability, permeability of waste rock masses largely depend on the lithology and grain size distribution of the loosened rocks composing waste rock dumps and their height distribution within a dump. The paper describes the findings of the study of the grain size distribution of waste rock masses of Kuzbass coal strip mines and the features of its spatial variations within the masses. The textures of the bulk masses and physical and technical properties of the stacked rocks were studied both at the Kuzbass waste rock sites and in laboratory conditions. The grain size distribution of the fine lump part of the dumps with the lump size up to 50 mm was investigated by sieve method according to GOST 12536–2014, and the medium and large lump part was studied using oblique photoplanimetry. The field observations showed that the bottom part of the rock dumps, dumped by peripheral bulldozer or excavator methods was composed of coarse fraction with average lump size of: dcr = 0.8–1 m, while the middle part, of rock lumps of dcr = 0.4–0.6 m, and the upper part, mainly of fine fraction with lump size of less than 0.1 m. The ratio of length, width, and thickness of the blasted rock lumps was 1:0.85:0.8, which corresponds to elongated-flattened shape of the lumps. This requires significant number of coordinates for describing the lump positions in the rock mass, as well as taking into account the moments of inertia when modeling the motion of such lumps until they reach a stable position. Up-to-date non-commercial or commercial software and corresponding hardware can be used to take into account non-isometric shape of the lumps when modeling their motion.

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