scholarly journals ANALYSIS OF BULBOUS BOW RESISTANCE WITH DIMPLE (BASIN) ON KRI CLASS STRATEGIC SEALIFT VESSEL (SSV) USING CFD SOFTWARE

JOURNAL ASRO ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 123
Author(s):  
Dwi Putra Maulana ◽  
Irfan Syarif Arief ◽  
Cahya Kusuma ◽  
Wawan Kusdiana ◽  
Mohammad Syaifi
Keyword(s):  
Surface Area ◽  
Final Conclusion ◽  
Total Resistance ◽  
Reduce Fuel Consumption ◽  
Friction Resistance ◽  
Ship Resistance ◽  
Cfd Applications ◽  
Bulbous Bow ◽  
Resistance Value

The function and role of the Strategic Sealift Vessel (SSV) ship type is very important. Modifications andchanges to improve the value of efficiency will be very necessary. This efficiency value is closely related to thevalue of Ship Resistance , where if the Resistance value goes down, the value of the ship's efficiency will rise.The increase in efficiency is then expected to reduce fuel consumption and increase speed. In several studies,ways have been improved to improve the condition, one of them is by adding a Dimple to the Surface Area ofthe ship, this modification will reduce the friction Resistance that the ship will receive by reducing the WettedSurface Area that the fluid will pass at certain speeds and conditions. . This modification will be applied to theship's Bulbous Bow section. In this way it is expected to improve the value of the Resistance produced by theBulbous Bow installed in the ship, without having to carry out significant changes or modifications and changethe shipbuilding of the existing Linesplane. Furthermore, the analysis is carried out by modeling using 2D and3D CAD Software and Model Experiments using CFD Applications. After carrying out the entire process ofRunning with the CFD Software to determine the value of the Ship Resistance . The final conclusion is in theform a reduction the value of vessel Total Resistance the Running Bow section of 31.53% in the 4th variationsand Fn used is 0,341.Keywords: Boulbous Bow, CFD, Dimple, Reduction, Resistance

scholarly journals Analysis of Effect of Bulbous Bow Shape to Ship Resistance in Catamaran Boat

2018 ◽  
Vol 159 ◽  
pp. 02058
Author(s):  
Deddy Chrismianto ◽  
Kiryanto ◽  
Berlian Arswendo Adietya
Keyword(s):  
Fluid Dynamic ◽  
The Body ◽  
Wave System ◽  
Total Resistance ◽  
Factors Affecting ◽  
Ship Resistance ◽  
Bow Wave ◽  
Main Factors ◽  
The One ◽  
Bulbous Bow

Ship resistance is one of the main factors affecting the design of a ship. Catamaran boat is a ship with small wet surface area that able to reduce drag and improve ship power. Generally, a bulbous bow is implemented to reduce wave resistance because the bulbous shape is believed to attenuate the bow wave system. Additionally, the bulbous bow also tends to reduce viscous resistance. When the flow around the body is smooth, the total ship resistance can be reduced significantly if the optimum bulbous bow is obtained. In this study, the main purpose is to get the bulbous bow shape in catamaran boat which produces the smallest ship resistance by using computational fluid dynamic (CFD). Generating the variation of the bulbous bow shapes apply the one-to-one correspondence of the cross section parameter (ABT) and lateral parameter (ABL). The result of investigation shows that application of bulbous bow on catamaran boat can reduce about 11-13% of total resistance of ship.

ANALISIS NILAI HAMBATAN TOTAL DENGAN PERUBAHAN SARAT KAPAL KM. KENDHAGA NUSANTARA 6

2020 ◽  
Vol 21 (1) ◽  
pp. 21-25
Author(s):  
Budi Utomo ◽  
Sulaiman Sulaiman
Keyword(s):  
Fluid Flow ◽  
Experimental Method ◽  
Calculation Method ◽  
Loading Condition ◽  
Total Resistance ◽  
Ship Resistance ◽  
The Difference ◽  
Resistance Value

The calculation of total resistance value is important of ship because  affects the speed of fluid flow that occurs, as well as the speed of the ship.So that in the designing new ships, sea trials are needed to find out whatever the preparedness of the ship is planned. The purpose is to obtain the value of the total resistance and the coefficient of ship resistance KM. Kendhaga Nusantara 6 uses the calculation method for each ship draught/loading condition. The Method used is experimental method with numerical value approach, Denny Mumford theory and Froude's number. The results show that the largest Total Resistance (Rt) is 5646,02 kN, it was found when speed of ship was 12 knots and draught ship 3,5 meters, with a coefficient value (Ct) of 7,757 x 10-3. The difference in value (Ct) is 0,032x10-3 or 0.41%, and it is still in the criteria because it is below 5%.

The formation of desilication products in the presence of kaolinite and halloysite – The role of surface area

2021 ◽  
pp. 105643
Author(s):  
Jose F. Gomes ◽  
Michael Davies ◽  
Peter Smith ◽  
Franca Jones
Keyword(s):  
Surface Area

Elucidating the Origin of the Toxicity of Nano-CeO2 to Chlorella pyrenoidosa：the Role of Specific Surface Area and Chemical Composition

2021 ◽  
Author(s):  
Changjian Xie ◽  
Yuhui Ma ◽  
Peng Zhang ◽  
Junzhe Zhang ◽  
Xiaowei Li ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Aquatic Environment ◽  
Cerium Dioxide ◽  
Environmental Application ◽  
Ecotoxicological Effects

With the increasing environmental application and discharge of nano cerium dioxide (nano-CeO2), it is urgent to fully understand its ecotoxicological effects on the aquatic environment. This study for the first...

scholarly journals Engineering Mesoporous NiO with Enriched Electrophilic Ni3+ and O− toward Efficient Oxygen Evolution

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 310 ◽  
Author(s):  
Xiu Liu ◽  
Zhi-Yuan Zhai ◽  
Zhou Chen ◽  
Li-Zhong Zhang ◽  
Xiu-Feng Zhao ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Low Cost ◽  
Large Surface Area ◽  
Nucleophilic Attack ◽  
Title Reaction ◽  
Highly Active ◽  
Decomposition Of Water ◽  
Uniform Mesopores

Tremendous efforts have been devoted to develop low-cost and highly active electrocatalysts for oxygen evolution reaction (OER). Here, we report the synthesis of mesoporous nickel oxide by the template method and its application in the title reaction. The as-prepared mesoporous NiO possesses a large surface area, uniform mesopores, and rich surface electrophilic Ni3+ and O− species. The overpotential of meso-NiO in alkaline medium is 132 mV at 10 mA cm−1 and 410 mV at 50 mA cm−1, which is much smaller than that of the other types of NiO samples. The improvement in the OER activity can be ascribed to the synergy of the large surface area and uniform mesopores for better mass transfer and high density of Ni3+ and O− species favoring the nucleophilic attack by OH− to form a NiOOH intermediate. The reaction process and the role of electrophilic Ni3+ and O− were discussed in detail. This results are more conducive to the electrochemical decomposition of water to produce hydrogen fuel as a clean and renewable energy.

The important role of surface area in the electrochemical behaviour of RuO2 electrodes

1977 ◽  
Vol 81 (2) ◽  
pp. 391-394 ◽  
Author(s):  
Laurence D. Burke ◽  
Oliver J. Murphy ◽  
John F. O'Neill
Keyword(s):  
Surface Area ◽  
Electrochemical Behaviour

scholarly journals A comparative review of the resistance of a 37,000 dwt Chemical Tanker based on experimental tests and calculations

2020 ◽  
Vol 1 ◽  
pp. 59-66
Author(s):  
Liviu Crudu ◽  
Radu Bosoancă ◽  
Dan Obreja
Keyword(s):  
Energy Efficiency ◽  
Experimental Tests ◽  
Full Scale ◽  
The Other ◽  
Towing Tank ◽  
Ship Resistance ◽  
Comparative Review ◽  
Cfd Applications ◽  
Energy Efficiency Design Index ◽  
Comparison Of The Results

The evaluation of ship resistance is of paramount importance having a decisive impact on the economic performances and efficiency depending on mission. If new IMO requirements through the Energy Efficiency Design Index (EEDI) are taken into account the necessity to have more and more accurate tools capable to consider the influences of different parameters became mandatory. The availability of towing tank facilities and the full scale trials are the practical means in order to be able to confirm the accuracy of theoretical formulations and to define the limits of CFD applications. Based on the results of the towing tank tests, a direct comparison with the results provided by classical methods and CFD computations can be systematically can be performed. On the other hand, the influences of the modifications operated on the fore part of the ship aretheoretically evaluated and compared with the towing tank results. Consequently, the paper is focused on the comparison of the results evaluated using different tools which have been carried out for a Chemical Tanker built by Constanta Shipyard Romania.

scholarly journals The role of clay content and mineral surface area for soil organic carbon storage in an arable toposequence

2021 ◽  
Author(s):  
Steffen A. Schweizer ◽  
Carsten W. Mueller ◽  
Carmen Höschen ◽  
Pavel Ivanov ◽  
Ingrid Kögel-Knabner
Keyword(s):  
Organic Carbon ◽  
Surface Area ◽  
Agricultural Soils ◽  
Mineral Soil ◽  
Clay Content ◽  
Clay Soils ◽  
Mineral Surface ◽  
Mineral Surface Area ◽  
The Impact

AbstractCorrelations between organic carbon (OC) and fine mineral particles corroborate the important role of the abundance of soil minerals with reactive surfaces to bind and increase the persistence of organic matter (OM). The storage of OM broadly consists of particulate and mineral-associated forms. Correlative studies on the impact of fine mineral soil particles on OM storage mostly combined data from differing sites potentially confounded by other environmental factors. Here, we analyzed OM storage in a soil clay content gradient of 5–37% with similar farm management and mineral composition. Throughout the clay gradient, soils contained 14 mg OC g−1 on average in the bulk soil without showing any systematic increase. Density fractionation revealed that a greater proportion of OC was stored as occluded particulate OM in the high clay soils (18–37% clay). In low clay soils (5–18% clay), the fine mineral-associated fractions had up to two times higher OC contents than high clay soils. Specific surface area measurements revealed that more mineral-associated OM was related to higher OC loading. This suggests that there is a potentially thicker accrual of more OM at the same mineral surface area within fine fractions of the low clay soils. With increasing clay content, OM storage forms contained more particulate OC and mineral-associated OC with a lower surface loading. This implies that fine mineral-associated OC storage in the studied agricultural soils was driven by thicker accrual of OM and decoupled from clay content limitations.

scholarly journals MiR-26a-5p inhibits GSK3β expression and promotes cardiac hypertrophy in vitro

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10371
Author(s):  
Liqun Tang ◽  
Jianhong Xie ◽  
Xiaoqin Yu ◽  
Yangyang Zheng
Keyword(s):  
Cell Surface ◽  
Cardiac Hypertrophy ◽  
Surface Area ◽  
Myocardial Cell ◽  
Immunofluorescence Staining ◽  
Cell Surface Area ◽  
Direct Target

Background The role of miR-26a-5p expression in cardiac hypertrophy remains unclear. Herein, the effect of miR-26a-5p on cardiac hypertrophy was investigated using phenylephrine (PE)-induced cardiac hypertrophy in vitro and in a rat model of hypertension-induced hypertrophy in vivo. Methods The PE-induced cardiac hypertrophy models in vitro and vivo were established. To investigate the effect of miR-26a-5p activation on autophagy, the protein expression of autophagosome marker (LC3) and p62 was detected by western blot analysis. To explore the effect of miR-26a-5p activation on cardiac hypertrophy, the relative mRNA expression of cardiac hypertrophy related mark GSK3β was detected by qRT-PCR in vitro and vivo. In addition, immunofluorescence staining was used to detect cardiac hypertrophy related mark α-actinin. The cell surface area was measured by immunofluorescence staining. The direct target relationship between miR-26a-5p and GSK3β was confirmed by dual luciferase report. Results MiR-26a-5p was highly expressed in PE-induced cardiac hypertrophy. MiR-26a-5p promoted LC3II and decreased p62 expression in PE-induced cardiac hypertrophy in the presence or absence of lysosomal inhibitor. Furthermore, miR-26a-5p significantly inhibited GSK3β expression in vitro and in vivo. Dual luciferase report results confirmed that miR-26a-5p could directly target GSK3β. GSK3β overexpression significantly reversed the expression of cardiac hypertrophy-related markers including ANP, ACTA1 and MYH7. Immunofluorescence staining results demonstrated that miR-26a-5p promoted cardiac hypertrophy related protein α-actinin expression, and increased cell surface area in vitro and in vivo. Conclusion Our study revealed that miR-26a-5p promotes myocardial cell autophagy activation and cardiac hypertrophy by regulating GSK3β, which needs further research.

scholarly journals ADDITION OF HYDROFOIL TO SHIP RESISTANCE ANALYSIS ON HALASAN CLASS BASED ON VALIDATION TEST RESULT

JOURNAL ASRO ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 105
Author(s):  
Sutrisno Sutrisno ◽  
Wawan Kusdiana ◽  
Ayip Rivai Prabowo ◽  
Muhammad Askhuri
Keyword(s):  
Surface Area ◽  
Load Condition ◽  
Maximum Speed ◽  
Main Function ◽  
Full Load ◽  
Ship Resistance ◽  
Validation Test ◽  
Hit And Run ◽  
Wet Surface ◽  
Test Result

KRI Halasan - 630 is one of the Fast Missile warships with a length of 60 Meters which apart of fast patrol boat class which belongs to TNI-AL. Accordance with the main function not only as a fast missile boat but also as a patrol ship killer, this ship was made to have a high ability in “hit and run”. Since the beginning of the manufacture and after being inaugurated as KRI in 2014 this ship is able to reach speed until 27 knot in full load. As time goes on the same conditions the speed that this ship can achieve is 25 knot at maximum speed. This can be caused by increase in value from the resistance of the ship. One way to reduce the value of the resistance of the ship is to minimize the Wet Surface Area(WSA) from the ship. By adding hydrofoil technology will produce lift force which could lift apart of the hull ship from the water so that Wet Surface Area from the ship will reduce. From the calculation, to lift on the hull of KRI Halasan Class 20 cm in full load condition at 25 knot knows that dimension for fore foil with tapered straight type are wingspan 4,6 m, wingroot 1,33 m, wingtip 0,5 m, and swept angle 11°. And dimension for aft foil with rectangular straight type are wingspan 5,3 m, wingroot and wingtip 1,365 m, and swept angle 0°. The ship resistance with hydrofoil is 265,5 KN, while in the same condition and speed from the ship without hydrofoil the value of ship resistance is 267 KN. By adding hydrofoil technology could reduce the ship resistance 1,5 KN. This values could make 19,29 KW or 25,86 Hp in power saving.Keywords : Hydrofoil technology, Ship Resistance, Halasan Class

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