CARACTERIZAÇÃO DOS ASPECTOS SEDIMENTOLÓGICOS E GRANULOMÉTRICOS ASSOCIADOS À FOZ DO RIO COREAÚ – CE, BRASIL

2019 ◽  
Vol 21 (2) ◽  
pp. 265-278
Author(s):  
Tarcyana Câmara Barroso ◽  
Paulo Roberto Silva Pessoa ◽  
Antônio Rodrigues Ximenes Neto ◽  
Jáder Onofre de Morais
Keyword(s):  
Grain Size ◽  
River Mouth ◽  
Fine Sand ◽  
Fine Grained ◽  
Quartz Sands ◽  
Geomorphological Units ◽  
Marine Influence ◽  
Del Rio ◽  
Atmospheric Systems ◽  
Fine Gravel

A zona costeira é um ambiente dinâmico de transição que apresenta uma interface entre os sistemas continentais, marinhos e atmosféricos. A área de estudo se localiza no município de Camocim-CE na região da foz do rio Coreaú, compreendendo também áreas adjacentes em ambas às margens. O objetivo deste trabalho foi analisar os aspectos deposicionais a partir da granulometria dos sistemas ambientais costeiros, para caracterização sedimentológica das principais unidades geomorfológicas da foz do rio Coreaú. Em campo foram coletadas amostras superficiais de três sistemas litorâneos – Duna; Estirâncio e Estuário. A sedimentação da área estudada é controlada pela influência marinha, com a predominância de areias quartzosas muito fina no subsistema duna e estuário. No estirâncio defronte a falésia costeira na margem esquerda houve predominância de cascalho fino. Já o estirâncio da Ilha do amor apresentou areia grossa e muito fina no estirâncio superior e inferior, respectivamente.Palavras-chave: Rio Coreaú; Sedimentologia; Granulometria. ABSTRACTThe coastal zone is a dynamic transition between the continental, marine, and atmospheric systems. The study area is located in the Coreaú river mouth, Camocim-CE. The aim was to characterize the depositional aspects from the grain size and sedimentology of coastal environmental systems to characterize the main geomorphological units. It was collected superficial samples of three coastal systems - Dune; Foreshore and Estuary. The sedimentation is controlled by the marine influence, with the predominance of very fine-grained quartz sands in the dune and estuary. In the foreshore of the coastal cliff at the left margin there was a predominance of fine gravel, as well as coarse and very fine sand in the upper and lower foreshore, respectively (Ilha do Amor).Keywords: Coreaú River; Sedimentology; Grain Size. RESUMEN La zona costera es un entorno dinámico de transición que presenta una interfaz entre los sistemas continentales, marinos y atmosféricos. La zona de investigación está ubicada en la ciudad de Camocim-CE, en la desembocadura del río Coreaú, y además comprende zonas adyacentes en ambas márgenes. El objetivo de la investigación fue caracterizar los aspectos deposicionales desde la granulometría de los sistemas ambientales costeros presentes en la zona, para caracterización sedimentario de las principales unidades geomorfológicas de la desembocadura del río Coreaú. La continuación se recogieron muestras superficiales de tres sistemas litorales – Duna; estrán y estuario. La sedimentación del área está controlada por la influencia marina, con la predominancia de arenas cuarzo muy fina en el subsistema duna y estuario. En la zona intermareale frente al acantilado costero en la margen izquierda hubo predominancia de arena fina. Ya en la zona intermareale de la Ilha do Amor presentó arena gruesa y muy fina en la estrán superior e inferior, respectivamente.Palabras clave: Río Coreaú; sedimentología; granulometría.

scholarly journals Universal relation with regime transition for sediment transport in fine-grained rivers

2019 ◽  
Vol 117 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Hongbo Ma ◽  
Jeffrey A. Nittrouer ◽  
Baosheng Wu ◽  
Michael P. Lamb ◽  
Yuanfeng Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Sediment Load ◽  
Yellow River ◽  
Fine Sand ◽  
Sediment Flux ◽  
Universal Relation ◽  
Sediment Grain Size ◽  
Fine Grained ◽  
Predictive Algorithm ◽  
Sediment Size

Fine-grained sediment (grain size under 2,000 μm) builds floodplains and deltas, and shapes the coastlines where much of humanity lives. However, a universal, physically based predictor of sediment flux for fine-grained rivers remains to be developed. Herein, a comprehensive sediment load database for fine-grained channels, ranging from small experimental flumes to megarivers, is used to find a predictive algorithm. Two distinct transport regimes emerge, separated by a discontinuous transition for median bed grain size within the very fine sand range (81 to 154 μm), whereby sediment flux decreases by up to 100-fold for coarser sand-bedded rivers compared to river with silt and very fine sand beds. Evidence suggests that the discontinuous change in sediment load originates from a transition of transport mode between mixed suspended bed load transport and suspension-dominated transport. Events that alter bed sediment size near the transition may significantly affect fluviocoastal morphology by drastically changing sediment flux, as shown by data from the Yellow River, China, which, over time, transitioned back and forth 3 times between states of high and low transport efficiency in response to anthropic activities.

Fiber Concrete for 3-D Additive Technologies

2019 ◽  
Vol 974 ◽  
pp. 367-372 ◽  
Author(s):  
Sergey V. Klyuev ◽  
Andrey V. Shevchenko ◽  
E.S. Shorstova
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Additive Technologies ◽  
Fine Aggregate ◽  
Cement Ratio ◽  
Fine Grained ◽  
Fiber Concrete ◽  
Concrete Placement

Fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

scholarly journals PROSES SEDIMENTASI SUNGAI KALIJAGA, DAN SUNGAI SUKALILA PERAIRAN CIREBON

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Deny Setiady ◽  
Asep Permana
Keyword(s):  
Grain Size ◽  
Size Range ◽  
River Mouth ◽  
Fine Sand ◽  
Silty Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Medium Size ◽  
Sandy Silt ◽  
Bathymetric Map

Berdasarkan hasil analisis besar butir sebanyak 36 percontoh sedimen permukaan dasar laut di Perairan Cirebon, didapatkan 4 jenis sedimen: lanau, lanau pasiran, pasir lanauan dan pasir. Sedimen lanau, lanau pasiran, dan pasir, tersebar di lepas pantai Cirebon dan muara Sungai Kalijaga, sedangkan pasir lanauan di muara sungai Sukalila. Dari Peta Batimetri terlihat daerah dangkal di sekitar muara Sungai Kalijaga. Sedimen paling tebal terdapat di sekitar muara Sungai Kalijaga dan Sungai Sukalila. Sedimen tersebut tersebar ke arah lepas pantai dan ke daerah rencana lokasi pelabuhan. Di muara Sungai Kalijaga sedimennya berupa pasir. Berdasarkan plot pada grafik antara ukuran besar butir terhadap persen frekuensi, didapatkan hasil sedimen dengan persen frekuensi yang tinggi antara 2.25 phi - 2.75 phi atau pasir sedang sampai pasir halus. Berdasarkan grafik frekuensi kumulatif terhadap besar butir terdapat 2 cara transpor yaitu traksi untuk butiran pasir sedang dan saltasi untuk kisaran butiran lanau sampai pasir halus. Kata Kunci : S. Kalijaga, S. Sukalila, Cirebon, besar butir, sedimen Based on grain size analysis of 36 seafloor surficial sediment samples from Cirebon Water; there are 4 types of sediments silt, sandy silt, silty sand and sand. Silt, sandy silt and sand are distributed offshore of Cirebon and in the river mouth of Kalijaga, while silty sand is in the river mouth of Sukalila. From the bathymetric map the shallow water can be observed in Kalijaga river mouth. The thicker sediments are found in Kalijaga mouth and Sukalila river. These sediments have been transported to the offshore and to the proposed Harbour location. Sediment in Kalijaga river mouth is sand. Based on graphic presentation between grain size and percent frequencies, it indicates that the percentage of higher frequencies ranges between 2.25 TO 2.75 phi. Based on the cumulative frequency to grain size graphic, there are two transport modes: traction for medium size sand and saltation for grain size range silt to fine sand. Keywords : Kalijaga River, Sukalila River, Cirebon, grain size, sediment

scholarly journals FIBER CONCRETE FOR 3-D ADDITIVE TECHNOLOGIES

2020 ◽  
Vol 2 (4) ◽  
pp. 14-20 ◽  
Author(s):  
Sergey Klyuev ◽  
Aleksandr Klyuev ◽  
Elena Shorstova
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Additive Technologies ◽  
Fine Aggregate ◽  
Cement Ratio ◽  
Fine Grained ◽  
Fiber Concrete ◽  
Concrete Placement

fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

Dispersal and Geochemistry of Surface Sediments in Halls Bay, North-Central Newfoundland: Application to Mineral Exploration

1975 ◽  
Vol 12 (8) ◽  
pp. 1346-1361 ◽  
Author(s):  
Roger M. Slatt
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Shallow Water ◽  
Mineral Exploration ◽  
Clay Content ◽  
Fine Sand ◽  
Grain Size Effect ◽  
North Central ◽  
Sediment Dispersal ◽  
Fine Grained

Surficial palimpsest sediments in Halls Bay, north-central Newfoundland, are mixtures of gravel, sand, and mud deposited from a number of sources in varying quantities from late Wisconsinan to the present time. Shallow water gravel originated as till and glacio-fluvial outwash. Gravel in deep water probably is ice-rafted. Sand and mud, which occurs with shallow water gravel and in deeper water, is a combination of fluvial material and material winnowed out of till and outwash by shallow water waves and currents during early marine transgression. There also may be a contribution of fine-grained sediment from the adjacent shelf.Gravel (coarser than [Formula: see text]), very fine sand (3 to [Formula: see text]) and coarse silt (4 to [Formula: see text]) modal grain-size classes predominate in the sediments. The very fine sand mode occurs on the west side of the inlet and the coarse silt mode occurs on the east side regardless of water depth, indicating net or active easterly dispersal of fine-grained sediment. This dispersal path may result from the presence in Halls Bay of a counterclockwise gyre of the Labrador Current that has developed since early transgression, which suggests the sediment surface is adjusting to the Halls Bay modern hydraulic regime.Sandy and muddy sediments are composed of quartz, feldspar, amphibole, illite, chlorite, montmorillonite, organic matter, CaCO3, and FeS. Major, minor, and trace element concentrations vary with grain-size, owing to the different proportions of these components in different size fractions. Calculation of an average chemical composition of sediments is biased because of this grain-size effect. The grain-size effect on chemistry of a suite of sediments can be accounted for by ratioing element concentrations to clay content.Plots of the ratio trace metal concentration/clay content vs. clay content for six trace metals indicate anomalous Cu concentrations occur in surface sediments along the east side of Halls Bay in the direction of fine-grained sediment dispersal. The anomalous Cu is derived from onshore mineralization in Lushs Bight Group volcanic rocks, which Occur along the west side of the inlet.The results provide an example of the applicability of marine sedimentologic/sedimentary geochemical investigations to mineral exploration. Local geochemical anomalies in sediments can be detected by routine analysis of total metal content of bulk samples provided the grain-size effect on chemistry is accounted for. The anomalous metal can be traced to its onshore source by evaluating sediment dispersal paths from textural variations.

scholarly journals Submarine lava deltas of the 2018 eruption of Kīlauea volcano

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
S. Adam Soule ◽  
Michael Zoeller ◽  
Carolyn Parcheta
Keyword(s):  
Grain Size ◽  
Pore Pressure ◽  
Mechanistic Model ◽  
Large Fraction ◽  
Volcanic Hazards ◽  
Lava Flows ◽  
Coarse Grained ◽  
Fine Grained ◽  
Fine Grain ◽  
Delta Formation

AbstractHawaiian and other ocean island lava flows that reach the coastline can deposit significant volumes of lava in submarine deltas. The catastrophic collapse of these deltas represents one of the most significant, but least predictable, volcanic hazards at ocean islands. The volume of lava deposited below sea level in delta-forming eruptions and the mechanisms of delta construction and destruction are rarely documented. Here, we report on bathymetric surveys and ROV observations following the Kīlauea 2018 eruption that, along with a comparison to the deltas formed at Pu‘u ‘Ō‘ō over the past decade, provide new insight into delta formation. Bathymetric differencing reveals that the 2018 deltas contain more than half of the total volume of lava erupted. In addition, we find that the 2018 deltas are comprised largely of coarse-grained volcanic breccias and intact lava flows, which contrast with those at Pu‘u ‘Ō‘ō that contain a large fraction of fine-grained hyaloclastite. We attribute this difference to less efficient fragmentation of the 2018 ‘a‘ā flows leading to fragmentation by collapse rather than hydrovolcanic explosion. We suggest a mechanistic model where the characteristic grain size influences the form and stability of the delta with fine grain size deltas (Pu‘u ‘Ō‘ō) experiencing larger landslides with greater run-out supported by increased pore pressure and with coarse grain size deltas (Kīlauea 2018) experiencing smaller landslides that quickly stop as the pore pressure rapidly dissipates. This difference, if validated for other lava deltas, would provide a means to assess potential delta stability in future eruptions.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

scholarly journals Strain-Rate and Grain‒Size Effects in Ice

1987 ◽  
Vol 33 (115) ◽  
pp. 274-280 ◽  
Author(s):  
David M. Cole
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Transition Point ◽  
Boundary Migration ◽  
Peak Stress ◽  
Strain Rates ◽  
Thin Sections ◽  
Fine Grained ◽  
Lower Strain ◽  
Polycrystalline Ice

AbstractThis paper presents and discusses the results of constant deformation-rate tests on laboratory-prepared polycrystalline ice. Strain-rates ranged from 10−7to 10−1s−1, grain–size ranged from 1.5 to 5.8 mm, and the test temperature was −5°C.At strain-rates between 10−7and 10−3s−1, the stress-strain-rate relationship followed a power law with an exponent ofn= 4.3 calculated without regard to grain-size. However, a reversal in the grain-size effect was observed: below a transition point near 4 × 10−6s−1the peak stress increased with increasing grain-size, while above the transition point the peak stress decreased with increasing grain-size. This latter trend persisted to the highest strain-rates observed. At strain-rates above 10−3s−1the peak stress became independent of strain-rate.The unusual trends exhibited at the lower strain-rates are attributed to the influence of the grain-size on the balance of the operative deformation mechanisms. Dynamic recrystallization appears to intervene in the case of the finer-grained material and serves to lower the peak stress. At comparable strain-rates, however, the large-grained material still experiences internal micro-fracturing, and thin sections reveal extensive deformation in the grain-boundary regions that is quite unlike the appearance of the strain-induced boundary migration characteristic of the fine-grained material.

scholarly journals New Brightener for Zn-Fe Alloy Plating from Sulphate Bath

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
B. M. Praveen ◽  
T. V. Venkatesha
Keyword(s):  
Grain Size ◽  
Metal Ion ◽  
Condensation Product ◽  
Spectroscopic Studies ◽  
Sem Images ◽  
Alloy Electrodeposition ◽  
Fine Grained ◽  
Polarization Studies ◽  
Uv Visible ◽  
Sulphate Bath

Zn-Fe alloy electrodeposition was carried out in the presence of condensation product 2-{[(1E)-(3,4-dimethoxyphenyl)methylidene]amino}-3-hydroxypropanoic acid formed between veratraldehyde and serine in acid sulphate bath. Hull cell was used for optimizing the operating parameters and bath constituents. During deposition, the potential was shifted towards cathodic direction in the presence of addition agents and brightener. The polarization studies show that deposition taking place in basic bath and optimum bath was 1.08 and 1.15 V, respectively. Current efficiency and throwing power were reached around 85% and 26%, respectively. The SEM images of bright deposit indicated its fine-grained nature and appreciable reduction in the grain size. XRD studies have showed that the grain size of the deposit generated from optimum bath was 16 nm. UV-visible spectroscopic studies confirm the formation of complex between metal ion and brightener.

scholarly journals Influence of Steel Grain Size on Residual Stress in Grinding Processing

2010 ◽  
Vol 638-642 ◽  
pp. 2389-2394 ◽  
Author(s):  
Masahide Gotoh ◽  
Katsuhiro Seki ◽  
M. Shozu ◽  
Hajime Hirose ◽  
Toshihiko Sasaki
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Grain Size ◽  
Stress State ◽  
Mechanical Grinding ◽  
Fine Grained ◽  
Residual Stress State ◽  
Analysis Methods ◽  
Average Grain Size ◽  
Fine Grained Steels

The fine-grained rolling steels NFG600 and the conventional usual rolling steels SM490 were processed by sand paper polishing and mechanical grinding to compare the residual stress generated after processing. The average grain size of NFG600 and SM490 is 3 μm and 15μm respectively. Therefore improvement of mechanical properties for such fine-grained steels is expected, it is important to understand the residual stress state of new fine-grained materials with processing. In this study, multi axial stresses of two kinds of specimens after polishing and grinding were measured by three kinds of analysis methods including cos-ψ method. As a result, as for σ33, the stress of NFG was compression, though that of SM490 was tension.

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