scholarly journals Foraminifera On The Beach Of Malalayang Dua

2018 ◽  
Vol 6 (2) ◽  
pp. 114
Author(s):  
Petrick Billy ◽  
Jane M. Mamuaja ◽  
Royke M. Rampengan ◽  
Medy Ompi ◽  
Esry T. Opa ◽  
...  
Keyword(s):  
Grain Size ◽  
Coarse Grained ◽  
Marine Waters ◽  
Inorganic Particles ◽  
Fine Sediments ◽  
Surrounding Environment ◽  
Loose Sediment ◽  
Sediment Sampling ◽  
Beach Sediments ◽  
Organic Particles

Beach as one on the landform that reflects the work of hydro-oceanographic factors, generally in the form of loose sedimentary material. Loose sediment is a collection of organic and inorganic particles that accumulate widely and are irregular in shape. One example of organism in marine waters that contributes to the availability of organic particles in the beach landform is foraminifera. Foraminifera is a single-celled organism that has the ability to form shells from substances of CaCO3 which originate from itself or from the surrounding environment. This study was aimed to classify physical sediments on the Malalayang Dua beach according to the points of sediment sampling, and see how the composition of foraminifera in the beach area and analyze the presence of foraminifera in relation to the granulometry of beach sediments. From the result of the study, it is found that the composition of grain size of sediment on the beach of Malalayang Dua is different, in stasion 1A, 1B, 2A, and 2B the sediment were mostly composed by fine grains while in station 3A and 3B were of coarse-grained sediment. A number of a species of foraminifera (dead test) was found in the study, and the number of tests was highes in fine sediments compared to coarse sediment.Keywords : Beach Landform, Malalayang Dua Coast, Foraminifera ABSTRAKGisik sebagai salah satu bentuklahan yang merefleksikan kerja faktor-faktor hidro-oseanografi, umumnya berwujud material sedimen lepas. Sedimen lepas adalah kumpulan partikel organik dan anorganik yang terakumulasi secara luas dan bentuknya tidak beraturan. Salah satu organisme di perairan laut yang berkontribusi terhadap ketersediaan partikel organik di gisik adalah foraminifera. Foraminifera merupakan organisme bersel tunggal yang mempunyai kemampuan membentuk cangkang dari zat-zat CaCO3yang berasal dari dirinya sendiri atau dari lingkungan sekitarnya. Penelitian ini bertujuan untuk mengelompokkan sedimen gisik di pantai Malalayang Dua menurut titik-titik pengambilan sampel sedimen, dan melihat bagaimana komposisi foraminifera di kawasan gisik serta menganalisis keberadaan foraminifera dalam kaitannya dengan granulometri sedimen gisik. Dari hasil penelitian komposisi ukuran butir sedimen pada lahan gisik di pantai Malalayang Dua berbeda menurut stasiun yang ditetapkan, di ruang pantai ke arah Timur yaitu stasiun 1A, 1B, 2A, 2B komposisi sedimennya berukuran halus, sedangkan di ruang pantai ke arah Barat yaitu stasiun 3A dan 3B komposisi sedimennya berukuran kasar, komposisi sedimen di setiap stasiun gisik litoral dan sublitoral menampilkan adanya perbedaan tingkat kekasaran partikel sedimen. Dari hasil penelitian ditemukan 9 cangkang foraminifera. Pada komposisi sedimen gisik yang berukuran halus ditemukan jumlah cangkang foraminifera yang lebih banyak dibandingkan dengan gisik yang komposisi sedimen berukuran kasar.Kata kunci : Lahan Gisik, Pantai Malalalayang Dua, Foraminifera

ANALYSIS OF THE MODERN GRAIN-SIZE COMPOSITION VARIABILITY OF THE ANAPA BAY-BAR BEACH SEDIMENTS

2018 ◽  
Author(s):  
В. Крыленко ◽  
V. Krylenko ◽  
Р. Косьян ◽  
R. Kos'yan ◽  
М. Крыленко ◽  
...  
Keyword(s):  
Grain Size ◽  
Bottom Sediments ◽  
Size Structure ◽  
Size Composition ◽  
Potential Danger ◽  
Grain Size Composition ◽  
Beach Sediments ◽  
Sediment Particles ◽  
Sand Material

The results of realized in 2010 field researches of the spatial and time grain-size structure variability of beach and bottom sediments of the bay-bar Anapskaya southern part are presented in this paper. Irretrievable carrying out of sediment particles to depths more than 7 m intensifies with their size decrease to 0,1 mm. As over 70 % bottom and about 60 % beach sediments are presented by fractions less 0,16 mm on bay-bar Anapskaya southern part, namely at this part there is sand material massive carrying out to depth. Potential danger of the investigated site geosystem degradation is revealed.

ACCUMULATION OF PLASTIC FRAGMENTS AND MICROPLASTICS ON THE BEACHES IN THE SOUTH-EAST BALTIC SEA

2017 ◽  
Author(s):  
Lilia Khatmullina ◽  
Lilia Khatmullina ◽  
Elena Esiukova ◽  
Elena Esiukova
Keyword(s):  
Baltic Sea ◽  
Size Range ◽  
Anthropogenic Pollution ◽  
The South ◽  
The Baltic Sea ◽  
Quantitative Distribution ◽  
Sediment Sampling ◽  
Beach Sediments ◽  
Kaliningrad Region ◽  
The Baltic

The sediment sampling from different areas of the beaches in the south-eastern part of the Baltic Sea (in Kaliningrad region) was executed for the purpose of studying the quantitative and qualitative composition of the microplastics particles (range 0.5-5 mm). Preference is given to those beaches that are exposed to maximum anthropogenic pollution. From June, 2015 to January, 2016, there were 14 expeditions along the coastline of the Baltic Sea (in Kaliningrad region) to collect experimental materials. The majority of samples were collected on the most recent flotsam deposited at “wracklines”, in the supralittoral zone. The primary examination of those samples revealed the presence of abundant microplastic particles of the required size range (0.5-5 mm). Quantitative distribution of microplastics in beach sediments was obtained in milligrams per gram of sediment and milligrams per m2: on average 0.05-2.89 (mg per gram of sediment) and 370-7330 (mg per m2), accordingly.

scholarly journals Statistical Modeling of Fine Sediments Dredged Using a Variable Area Dredging Suction Head to Improve Water Quality

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 98
Author(s):  
Leigh A. Provost ◽  
Robert Weaver ◽  
Nezamoddin N. Kachouie
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Sedimentation Rates ◽  
Agricultural Lands ◽  
Design Efficiency ◽  
Fine Sediments ◽  
Grain Sizes ◽  
Fine Grain ◽  
Sediment Sampling ◽  
Improve Water Quality

The changing climate affects the agricultural lands, and, in turn, the changes in agricultural lands alter the watershed. A major concern regarding waterbodies is the increased sedimentation rates due to climate change. To improve the water quality, it is crucial to remove fine sediments. Using current environmental dredging methods is challenging because of the sediment volumes that must be dredged, the absence of nearby disposal sites, and the shoreline infrastructure at the dredging locations. To address these issues, we used a surgical dredging method with a variable area suction head that can easily maneuver around the docks, pilings, and other infrastructures. It can also isolate the fine grain material to better manage the dredged volumes in the seabed where nutrients are typically adhered. To this end, a statistical analysis of the dredged samples is essential to improve the design efficiency. In this work, we collected several samples using a variable area suction head with different design settings. The collected samples using each design setting were then used to model the distributions of the different grain sizes in the dredged sediments. The proposed statistical model can be effectively used for the prediction of sediment sampling outcomes to improve the gradation of the fine sediments.

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.

The Effect of Grain Size on Superplastic Deformation of Ti-6Al-4V Alloy

2007 ◽  
Vol 551-552 ◽  
pp. 387-392 ◽  
Author(s):  
Wen Juan Zhao ◽  
Hua Ding ◽  
D. Song ◽  
F.R. Cao ◽  
Hong Liang Hou
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Superplastic Deformation ◽  
Initial Strain Rate ◽  
Deformation Mode ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Coarse Grained ◽  
Transmission Electron ◽  
Grain Growth Model

In this study, superplastic tensile tests were carried out for Ti-6Al-4V alloy using different initial grain sizes (2.6 μm, 6.5μm and 16.2 μm) at a temperature of 920°C with an initial strain rate of 1×10-3 s-1. To get an insight into the effect of grain size on the superplastic deformation mechanisms, the microstructures of deformed alloy were investigated by using an optical microscope and transmission electron microscope (TEM). The results indicate that there is dramatic difference in the superplastic deformation mode of fine and coarse grained Ti-6Al-4V alloy. Meanwhile, grain growth induced by superplastic deformation has also been clearly observed during deformation process, and the grain growth model including the static and strain induced part during superplastic deformation was utilized to analyze the data of Ti-6Al-4V alloy.

Structure of Low Cobalt Alloy for Permanent Magnets of Basis System Fe-Cr-Co at Complex Two-Level Loading in Isothermal Conditions

2007 ◽  
Vol 539-543 ◽  
pp. 2928-2933 ◽  
Author(s):  
V.S. Yusupov ◽  
A.I. Milyaev ◽  
Galia F. Korznikova ◽  
Alexander V. Korznikov ◽  
J.K. Kovneristii
Keyword(s):  
Grain Size ◽  
Active Zone ◽  
Single Phase ◽  
Permanent Magnets ◽  
Phase Region ◽  
The Body ◽  
Coarse Grained ◽  
Isothermal Conditions ◽  
Basis System ◽  
Level Loading

Results of experimental research into evolution of the structure and microhardness of the hard magnetic Fe-30Cr-8Co-0,7Ti-0,5V-0,7Si alloy during complex two-level loading (compression + torsion) in isothermal conditions at various temperatures in single-phase region are reported. It was revealed that the deformation leads to a strong refinement of initial coarse-grained structure in the whole volume of the sample, however the generated structure is non-uniform through the body of the sample. In an active zone of deformation, near to mobile head, there is a microcrystalline layer with a grain size of about 5 microns which thickness poorly depends on the formation. With removal from the active zone of deformation the grain size increases, and microhardness decreases.

scholarly journals Rip current evidence by hydrodynamic simulations, bathymetric surveys and UAV observation

2017 ◽  
Author(s):  
Guido Benassai ◽  
Pietro Aucelli ◽  
Giorgio Budillon ◽  
Massimo De Stefano ◽  
Diana Di Luccio ◽  
...  
Keyword(s):  
Grain Size ◽  
High Resolution ◽  
Numerical Simulations ◽  
Current System ◽  
Current Evidence ◽  
Rip Current ◽  
Rip Currents ◽  
Transport Pathways ◽  
Fine Sediments ◽  
Scientific Challenge

Abstract. The prediction of the formation, spacing and location of rip currents is a scientific challenge that can be achieved by means of different complementary methods. In this paper the analysis of numerical and experimental data, including UAV observation, allowed to detect the presence of rip currents and rip channels at the mouth of Sele river, in the Gulf of Salerno, southern Italy. The dataset used to analyze these phenomena consisted of two different bathymetric surveys, a detailed sediment 5 analysis and a set of high-resolution wave numerical simulations, completed with satellite and UAV observation. The grain size trend analysis and the numerical simulations allowed to identify the rip current system, forced by topographically constrained channels incised on the seabed, which were detected by high resolution bathymetric surveys. The study evidenced that on the coastal area of the Sele mouth grain-size trends are controlled by the contribution of fine sediments, which exhibit suspended transport pathways due to rip currents and longshore currents. The results obtained were confirmed by satellite and UAV 10 observations in different years.

Mechanical Behavior and Stress-Induced Martensitic Transformation in Nanocrystalline Ti49.4Ni50.6 Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 470-474 ◽  
Author(s):  
Egor Prokofiev ◽  
Dmitriy Gunderov ◽  
Alexandr Lukyanov ◽  
Vladimir Pushin ◽  
Ruslan Valiev
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Martensitic Transformation ◽  
Ultimate Tensile Strength ◽  
High Pressure Torsion ◽  
Coarse Grained ◽  
High Yield ◽  
D 20 ◽  
20 Nm ◽  
High Ultimate Tensile Strength

Amorphous-nanocrystalline Ti49.4Ni50.6 alloy in the shape of a disc 20 mm in diameter has been successfully produced using high pressure torsion (HPT). Application of HPT and annealing at temperatures of 300–550°C resulted in formation of a nanocrystalline (NC) structure with the grain size (D) about 20–300 nm. The HPT samples after annealing at Т = 400°C with the D= 20 nm possess high yield stress and high ultimate tensile strength (more than 2000 MPa). There is an area of strain-induced transformation B2-B19’ on the tensile curve of the samples with the grain size D =20 nm. The stress of martensitic transformation (σm) of samples is 450 MPa, which is three times higher than σm in the initial coarse-grained state (σm ≈ 160 MPa). The HPT samples after annealing at Т = 550°C with the D= 300 nm possess high ductility (δ>60 %) and high ultimate tensile strength (about 1000 MPa).

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