scholarly journals Formation and Changes of Multiple Sand Bars and Influence of Fine Sand Bed

1992 ◽  
Vol 36 ◽  
pp. 23-28
Author(s):  
Yuichiro FUJITA ◽  
Nobuhiro NAGATA ◽  
Yoshio MURAMOTO
Keyword(s):  
Fine Sand ◽  
Sand Bars

scholarly journals Quarternary Sediment Characteristics of Floodplain area: Study Case at Kampar River, Rumbio Area and Surroundings, Riau Province

2018 ◽  
Vol 3 (1) ◽  
pp. 63
Author(s):  
Yuniarti Yuskar ◽  
Dewandra Bagus Eka Putra ◽  
Muhammad Revanda
Keyword(s):  
River System ◽  
Fine Sand ◽  
Sediment Deposition ◽  
Sediment Supply ◽  
Lateral Spread ◽  
Stream Channel ◽  
Terrestrial Organic Matter ◽  
Depositional Facies ◽  
Meandering River ◽  
Sand Bars

The study area is located in some floodplains of meandering river environment along the Kampar River, Rumbio. Typical morphology of meandering river that found in this area can be classified as stream channel, floodplain, abandoned channel, and sand bars deposit. Meandering river system carries sediment supply by suspended and bed - load (mixed load) in conjunction with low energy into a particular characteristic on sediment deposition. This study aims to determine the characteristics of the sediments, changes in vertical and lateral spread of sediment deposition on the floodplain environment. This study conducted by field survey using a hand auger of 1.5m - 4m depth and trenching which is a layer that has been exposed of 1-2 meters depth. Further analysis had been carried out using granulometri method and core data analysis to determine the characteristics and depositional facies. Sediment deposit that formed along the Kampar River is the result of the main channel migration of Kampar River. The characteristic of quaternary sediment facies is coarse to gravelly sand on the bottom followed by fine to very fine sand with pattern fining upwards and silt to clay and abundant terrestrial organic matter at the uppermost layer. Depositional facies are determined based on the characteristics of sediment facies which can be grouped into a stream channel, oblique accretion deposits, sand bars and overbank deposits.

Adjustment mechanism of the sand bars in the jingjiang reach after the impounding the three gorges

2020 ◽  
Author(s):  
Xuhai Yang
Keyword(s):  
Negative Impact ◽  
Fine Sand ◽  
Deformation Characteristics ◽  
Three Gorges ◽  
Flow Process ◽  
Erosion And Deposition ◽  
Adjustment Mechanism ◽  
Sand Bars ◽  
The Three Gorges ◽  
River Bed

<p>After the application of the large reservoirs, the conditions of discharge and sediment are changed. Based on a large number of measured hydrological and topographic data, this paper studies the deformation characteristics of sandbars micro-geomorphology in sandy reach of jingjiang river after the impounding of the three gorges reservoir(TGD), and discusses the adjustment mechanism of sandbars. The result shows that the sandy bars showed the head scoured and the shrink of area, and the sandbars in the reach with revetment project was relatively stable.The evolution of the sandbars was mainly influenced by riverbed composition, discharge and sediment process and revetment project. The composition of the riverbed determined the scour resistance of the sandbars, while the change of flow process determined the location and property of scour and silting, and the amount of incoming sediment determined the extent of scour and silting, the implementation of revetment project was beneficial to sandbars stability. After the TGD operation, the erosion of the bars in the Jingjiang reach ranked the strongest when the discharges fall in 15000 m³/s~25000 m³/s. The duration of this flow range increased after the TGD operation in 2003, and the bars presented an erosion state. Due to the impacts of river bed armoring and the significantly reduced sediment, there existed certain interactive relationships between the adjustment in the erosion and deposition of bars and the changes in the percentage of the grain size belonging to 0.125<d<0.25mm. The reduction of the fine sand had a negative impact on the sedimentation of bars after erosion. The layout of the revetment project had a certain control effect on the sandy reach, but the unguarded sandy bars presented scour and deposition with the fluctuation of discharge and sediment process between years.</p>

ACCUMULATION-DEFLATIONARY PROCESSES ON MARINE SAND BARS COASTS OF THE SOUTHERN-EAST BALTIC

2018 ◽  
Author(s):  
Е. Бадюкова ◽  
E. Badyukova ◽  
Леонид Жиндарев ◽  
Leonid Zhindarev ◽  
Светлана Лукьянова ◽  
...  
Keyword(s):  
Sand Bars ◽  
Marine Sand ◽  
Wave Erosion ◽  
Dune Ridge ◽  
Sea Wave ◽  
Sea Coast

Modern accumulative and deflation forms of a coastal eolian relief on the sea coast of Kuronian and Vistula Spits are considered. It is established that on coastal barriers there are at the same time processes of accretion and degradation of a dune ridge and leaned against it foredune. Alternation of stable and erosive sites of a dune ridge is revealed. The last has destruction signs as with sea (wave erosion), and from the land side where the whirls of a wind stream creating numerous deflation basins in dune ridge have great value.

Impact of Nitrogen Management Practices on Total Nitrogen in the Fruits of High Productive Hamlin Orange Trees

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498e-498
Author(s):  
S. Paramasivam ◽  
A.K. Alva
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Fine Sand ◽  
Fruit Production ◽  
Perennial Crop ◽  
Total N ◽  
N Removal ◽  
Leaf N Concentration ◽  
N Rates ◽  
Orange Trees

For perennial crop production conditions, major portion of nutrient removal from the soil-tree system is that in harvested fruits. Nitrogen in the fruits was calculated for 22-year-old `Hamlin' orange (Citrus sinensis) trees on Cleopatra mandarin (Citrus reticulata) rootstock, grown in a Tavares fine sand (hyperthermic, uncoated, Typic Quartzipsamments) that received various N rates (112, 168, 224, and 280 kg N/ha per year) as either i) broadcast of dry granular form (DGF; four applications/year), or ii) fertigation (FRT; 15 applications/year). Total N in the fruits (mean across 4 years) varied from 82 to 110 and 89 to 111 kg N/ha per year for the DGF and FRT sources, respectively. Proportion of N in the fruits in relation to N applied decreased from 74% to 39% for the DGF and from 80% to 40% for the FRT treatments. High percentage of N removal in the fruits in relation to total N applied at low N rates indicate that trees may be depleting the tree reserve for maintaining fruit production. This was evident, to some extent, by the low leaf N concentration at the low N treatments. Furthermore, canopy density was also lower in the low N trees compared to those that received higher N rates.

Nutrient Concentrations in Soil Solution in an Alfisol under Grapefruit Production

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498d-498
Author(s):  
Z.L. He ◽  
A.K. Alva ◽  
D.V. Calvert ◽  
D.J. Banks ◽  
Y.C. Li
Keyword(s):  
Soil Solution ◽  
Fine Sand ◽  
Drainage Water ◽  
Tree Canopy ◽  
Nutrient Concentrations ◽  
Sour Orange ◽  
Parallel Study ◽  
Ph Measurements ◽  
The Mean ◽  
N Rates

A field experiment was conducted in a Riviera fine sand (Alfisol) with 25-year-old `White Marsh' grapefruit trees on Sour orange rootstock to monitor the downward transport of nutrients from fertilization practices. Fertilizer was applied as either dry granular broadcast (three applications/year) or fertigation (15 applications/year) at N rates of 56, 112, 168, and 336 kg/ha per year using a N:P:K blend (1.0:0.17:1.0). Soil solution was sampled bi-weekly from suction lysimeters, installed under the tree canopy, about 120 cm from the tree trunk, at two depths representing above (120 cm) and below (180 cm) the hard pan. The concentrations of K, Ca, and Mg were greater at the 180- than at 120-cm depth, whereas, the converse was true with respect to the concentration of P in soil solution. Over a 2-year period, the mean concentrations of P and K varied from 0.031-0.976 and 150-250 mg·L–1, respectively. Increased rate of fertilization also appeared to increase the concentrations of Ca and Mg in the soil solution. This could be due to effects of slight acidification of the soil with increased rates of ammonium form of N. A parallel study on pH measurements has shown evidence of soil acidification, under the tree canopy, with increased rates of ammonium fertilization. In a bedded grove, the soil solution above the hard pan is likely to seep into the water furrow, which is discharged into the drainage water.

Laboratory investigation of pullout behavior of strengthened geogrid with concrete pieces in fine sand

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Alireza Beyranvand ◽  
Seyed Hamid Lajevardi ◽  
Mahmoud Ghazavi ◽  
Seyed Mohammad Mirhosseini
Keyword(s):  
Laboratory Investigation ◽  
Fine Sand

Laboratory Tests on Engineering Properties of Wind-Blown Sand

2012 ◽  
Vol 170-173 ◽  
pp. 706-709
Author(s):  
Zhao Lin Jia ◽  
Shu Wang Yan ◽  
Zhi Liang Huo
Keyword(s):  
Water Content ◽  
Laboratory Tests ◽  
Fine Sand ◽  
Engineering Properties ◽  
Grain Composition ◽  
Factors Affecting ◽  
Compaction Curve ◽  
Main Factors ◽  
Dry And Wet Conditions ◽  
Compaction Properties

By means of laboratory tests and theoretical calculation, the physical, mechanical properties and compaction mechanism of the wind-blown sand are studied to deal with the problem of how to use the wind-blown sand as roadbed materials. It is revealed that water content doesn’t affect the compressibility and the shear strength of the wind-blown sand obviously and the wind-blown sand can be compacted both in dry and wet conditions. The compaction curve of the ordinary fine sand is consistent with that of wind-blown sand and the main factors affecting the compaction properties are the grain composition, water content and compaction work.

Specifications and testing of self-consolidating mortar designated for annular space grouting

2011 ◽  
Vol 38 (4) ◽  
pp. 422-432 ◽  
Author(s):  
Soo-Duck Hwang ◽  
Kamal H. Khayat ◽  
Richard Morin
Keyword(s):  
High Stability ◽  
Fine Sand ◽  
Underground Water ◽  
Experimental Program ◽  
Testing Protocol ◽  
Slump Flow ◽  
Nominal Size ◽  
Repair Mortars ◽  
Passing Ability ◽  
Good Filling

An experimental program was undertaken to evaluate the performance of self-consolidating mortar designed for filling small annular spaces for the rehabilitation of underground water line or sewage pipelines. The study also intended to establish a testing protocol to validate the workability of repair grout. All the investigated mixtures had good filling and passing ability with adequate retention of workability over 3 h. The repair mortars exhibited high stability with bleeding lower than 0.3% compared to 3% bleeding in the case of the reference neat cement grout. The reference grout had a lower plastic viscosity and higher slump flow values than the sanded repair grouts. A V-funnel with 30 mm × 30 mm overture and a flow cone with 12.7 mm overture are recommended for mortar made with concrete sand with a 5 mm nominal size and micro mortar with fine sand with a nominal size up to 3 mm, respectively.

scholarly journals Using of Microsilica for Strength Improvement of Fiber Reinforced Cementitious Surface Compounds

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
S. S. Shebl ◽  
Ibrahim S. Khalil ◽  
H. Shoukry
Keyword(s):  
Date Palm ◽  
Fine Sand ◽  
Structural Performance ◽  
Polypropylene Fibers ◽  
Hydration Products ◽  
Fiber Reinforced ◽  
Surface Compounds ◽  
Extension Work ◽  
Strength Improvement

This study represents an extension work to investigate the role of ultra fine sand (UFS) in enhancing the mechanical properties of fiber reinforced cementitious compounds. The micro-structural origins were identified by scanning electron microscope (SEM). About 50% of UFS had a diameter of less than 20 μm. Ordinary Portland Cement (OPC) was partially substituted by UFS at 3, 5, 7 and 10% by weight of binder. It was found that as UFS loadings increase, the flexural, compressive, and tensile strengths increased up to about 5% UFS loading by 12.9, 15.7 and 30.1%, respectively, thereafter, a decrease in these properties was observed. This can be attributed to the pozzolanic effect besides the filling effect of UFS resulting in enhancing the interfacial bonds between the sand grains and hydration products that makes the paste more homogeneous and dense. The effect of both short natural and artificial fiber loadings on the structural performance of compounds was also studied. Loadings of 2%, by weight, of short natural date palm leaves’ midribs fibers (DP) and artificial polypropylene fibers (PP) were added to the 5% UFS blended mix. An increase in both flexural and tensile strength was achieved, while a decrease in the compressive strength was observed.

The Metazoan Meiofauna in Its Biogeochemical Environment: The Case of an Antarctic Coastal Sediment

1998 ◽  
Vol 78 (2) ◽  
pp. 411-434 ◽  
Author(s):  
S. Vanhove ◽  
H.J. Lee ◽  
M. Beghyn ◽  
D. Van Gansbeke ◽  
S. Brockington ◽  
...  
Keyword(s):  
Organic Matter ◽  
Standing Stock ◽  
Austral Summer ◽  
Fine Sand ◽  
Coastal Sediment ◽  
Feeding Guild ◽  
Fresh Organic Matter ◽  
Benthic Environment ◽  
Metazoan Meiofauna ◽  
Deposit Feeding

The metazoan meiobenthos was investigated in an Antarctic coastal sediment (Factory Cove, Signy Island, Antarctica). The fine sands contained much higher abundances compared to major sublittoral sediments worldwide. Classified second after Narrangansett Bay (North Atlantic) they reached numbers of 13 × 106ind m-2. The meiofauna was highly abundant in the surface layers, but densities decreased sharply below 2 cm. Vertical profiles mirrored steep gradients of microbiota, chloropigments and organic matter and were coincident with chemical stratification. Spatial patchiness manifested especially in the surface layer. Nematodes dominated (up to 90%), andAponema, Chromctdorita, Diplolaimella, Daptonema, MicrolaimusandNeochromadoraconstituted almost the entire community. Overall, the nematode fauna showed a strong similarity with fine sand communities elsewhere. The dominant trophic strategies were epistrarum and non-selective deposit feeding, but the applied classification for feeding guild structure of the nematodes of Factory Cove is discussed. High standing stock, low diversity and shallow depth distribution may have occurred because of the high nutritive (chlorophyll exceeded lOOOmgm-2and constituted almost 50% of the organic pool) and reductive character of the benthic environment. These observations must have originated from the substantial input of fresh organic matter from phytoplankton and microphytobenthic production, typical for an Antarctic coastal ecosystem during the austral summer.

Sign in / Sign up

Export Citation Format

Share Document