scholarly journals Study on resistance and intact stability behavior of patrol boat using axe bow hull form to support surveillance activities in the Indonesia territorial sea

2021 ◽  
Vol 19 (3) ◽  
pp. 822-832
Author(s):  
Aulia Windyandari ◽  
Adi Yusim
Keyword(s):  
Total Resistance ◽  
Conservation Areas ◽  
Water Line ◽  
Stability Behavior ◽  
Fishery Resources ◽  
Stability Performance ◽  
Intact Stability ◽  
Primary Means ◽  
Fisheries Conservation ◽  
Principal Dimension

As a sovereign maritime country, Indonesia has an obligation to protect, maintain, and manage marine and fishery resources. Patrol boats as the primary means of monitoring marine and fishery resources are needed in response to several problems and threats that may occur, such as illegal fishing, destructive fishing, violations of zoning in fisheries conservation areas and others. Apart from having to be adequate on the number of units, the patrol boats must also have suitable technology to support pursuit operations and suppress violations. The main objective of this research is to investigate the total resistance and intact stability behavior of the developed axe bow hull geometry for the patrol boat hull. The preliminary design is started with the determination of the principal dimension of the patrol boat. Then the hull geometry configurations were made with the variation of the depth of bow and the water line spline type. In the case of the depth of bow, the bow with the additional depth of 30%, 40% and 50% of the draft was investigated. Otherwise, the water line spline type was configured as convex spline, concave spline and straight spline. According to the numerical analysis, the axe bow hull with the depth of bow of 30% and the straight spline type was presented the smallest total resistance performance. However, in the case of intact stability performance, all developed axe bow hull presented a similar righting moment lever arm (GZ curve). It is indicated that the total resistance of the axe bow hull is influenced by the depth of bow and water line spline type. Furthermore, those variables have a slight influence on intact stability performance.

scholarly journals On the Development of Catamaran Hull Form for Fish Processing Vessel to Support Domestic Fishing Activities in Indonesia

Naše more ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 175-188
Author(s):  
Ahmad Fauzan Zakki ◽  
◽  
Deddy Chrismianto ◽  
Aulia Windyandari ◽  
Rizaldy Ilham
Keyword(s):  
Dynamic Stability ◽  
High Speed ◽  
Equation Model ◽  
Fish Processing ◽  
Hull Form ◽  
Initial Stage ◽  
Intact Stability ◽  
Principal Dimension ◽  
Hull Forms ◽  
Resistance Performance

Several advantages of multihull, such as catamaran, have been extensively discussed in the previous research. Therefore, this research focuses on developing a catamaran hull form for the fish processing vessel hull. The initial stage is determining the principal dimension and exploring the configurations of catamaran hull forms. The existing high-speed craft catamarans have been adopted to determine the parent model main dimensions using a linear regression equation model. Otherwise, the catamarans single demi-hull geometry was developed by converting and modifying the parent model hull form with enlarging the hull displacement to achieve the deadweight capacity and service speed requirements. The demi-hull spacing configuration with s/L 0.17, s/L 0.20, s/L 0.30, and s/L 0.40 on the resistance characteristics, intact stability, and sea-keeping behaviour were also explored. Furthermore, the comparisons with the previously proposed monohull were presented. Regarding the hull resistance performance, the analysis indicated that the catamaran hull form had better total resistance characteristics than the monohull on the service speed over 23 knots. In the case of intact stability, the analysis results presented that the catamaran hull form has better intact stability characteristics than the monohull. The dynamic stability of the catamarans also gave better dynamic stability at the heeling angle below 41.57°. Otherwise, the catamarans with s/L 0.17 and s/L 0.20 have lower dynamic stability than the monohull at the heeling angle larger than 41.57° and 58.03°, respectively. In the sea-keeping performance, the catamaran hull has shown an excellent rolling motion required for the offshore environment loading/unloading process. The large demi hull spacing of the catamarans hull can reduce the effect of the wave creating load on the roll motion response at the Beam Sea.

Perception, epistemic issues in

2018 ◽  
Author(s):  
Brian P. McLaughlin
Keyword(s):  
Sense Perception ◽  
Logical Possibility ◽  
Optical Illusions ◽  
Water Line ◽  
Sour Milk ◽  
The World ◽  
Primary Means ◽  
Five Senses ◽  
The Senses ◽  
The Way

We learn about the world through our five senses: by seeing, hearing, smelling, tasting and feeling. Sense perception is a primary means by which we acquire knowledge of contingent matters of fact. We can also acquire such knowledge by, for instance, conscious reasoning and through the written and spoken testimony of others; but knowledge so acquired is derivative, in that it must be based, ultimately, on knowledge arrived at in more primary ways, such as by sense perception. We can perceive something without acquiring any knowledge about it; for knowledge requires belief, and we can perceive something without having any beliefs about it. Viewing any but the most simple visual scenes we see many things we form no beliefs about. However, when we perceive something, we are acquainted with it by its sensorially appearing (looking, sounding, smelling and so on) some way to us. For we see something if and only if it looks some way to us, hear something if and only if it sounds some way to us, and so on. When, based on how they appear, we form true beliefs about things we perceive, the beliefs sometimes count as knowledge. Often the way something appears is the way it is. The red, round tomato looks red and round; the sour milk tastes sour. But the senses are fallible. Sometimes the way something appears is different from the way it is. Appearances can fail to match reality, as happens to various extents in cases of illusion. There are, for instance, optical illusions (straight sticks look bent at the water line) and psychological ones (despite being exactly the same length, the Müller-Lyer arrows drawings look different in length). In such cases, looks are misleading. The ever-present logical possibility of illusion makes beliefs acquired by perception fallible: there is no absolute guarantee that they are true. But that does not prevent them from sometimes counting as knowledge – albeit fallible knowledge. Recognitional abilities enable us to obtain knowledge about things from how they perceptually appear. Sense perception thus acquaints us with things in a way that contributes to positioning us to acquire knowledge about them. The central epistemic issues about sense perception concern its role in so positioning us.

scholarly journals Intact stability and seakeeping characteristics of autonomous surface vehicle (asv) using swath hullform to support bathymetry survey activities on the coastal area

2018 ◽  
Vol 177 ◽  
pp. 01001 ◽  
Author(s):  
Zakki Ahmad Fauzan ◽  
Aris Triwiyatno ◽  
Bandi Sasmito ◽  
Muhammad H. Nubly
Keyword(s):  
Leading Edge ◽  
Hull Form ◽  
Stability Performance ◽  
Autonomous Surface Vehicle ◽  
Intact Stability ◽  
Long Time ◽  
Form Design ◽  
Hull Form Design ◽  
The Stability ◽  
Resistance Stability

The information is an important thing to search a new resource. In this decade, with leading-edge technology is easier to find any information about our earth. Thus, that is must be explored by the ships. The exploration works usually take a long time, and for convenience, the unmanned technology is much promised. In this research, we focused on the autonomous surface vehicle for bathymetry survey. To design the ASV, we must consider the reliability, efficiency, and safety. To reach those three components, the analysis of resistance, stability and wave response are necessary. Therefore, the hull form design is focused on Small Waterplane Area Twin Hull (SWATH) hull form. According to the numerical analysis, the proposed SWATH hull form of ASV is suitable for bathymetry activities. It can be proved by the stability performance which the maximum value of GZ is at 26.40. The resistance calculation result is indicated that the drag of coefficient of this hull form is about 0.013.

scholarly journals Development of Monohull Fish Processing Vessel Hullform to Support Domestic Fishing Activities in Indonesia

2019 ◽  
Vol 9 (1) ◽  
pp. 441-447
Keyword(s):  
Fluid Dynamic ◽  
Fish Processing ◽  
Hull Form ◽  
Fishing Boat ◽  
Initial Stage ◽  
Dynamic Methods ◽  
Intact Stability ◽  
Strip Theory ◽  
Principal Dimension ◽  
Hull Forms

This research is focused on the development of the design and prototype of monohull fish processing vessel hullform to support fishing activities such as catching fish, collecting fish from the smaller boats and processing fish catches. The extensive on-board facilities in the fish processing vessel are maintaining the freshness of the catch and improving the quality of catch fish than traditional fishing boat. The initial stage of this study is determining the principal dimension and exploring of the configurations of monohull hull forms. Furthermore, the investigation of resistance characteristics, intact stability and seakeeping behavior was carried out using strip theory and computational fluid dynamic methods. Regarding the performance of the hulls resistance, the analysis indicates that the hull form with smaller block coefficients showed better resistance characteristics. In the case of intact stability, the results of the analysis showed that the model 2 of monohull hull form showed better intact stability characteristics compared to the other models

scholarly journals Rotor-Bearing System Stability Performance Comparing Hybrid versus Conventional Bearings

2005 ◽  
Vol 2005 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Julio Gomez-Mancilla ◽  
Valeri Nosov ◽  
Gerardo Silva-Navarro
Keyword(s):  
Single Injection ◽  
Journal Bearings ◽  
System Stability ◽  
Injection Port ◽  
Stability Behavior ◽  
Stability Performance ◽  
Bearing Design ◽  
Hybrid Bearing ◽  
Feeding Pressure ◽  
Conventional Type

New closed-form expressions for calculating the linear stability thresholds for rigid and flexible Jeffcott systems and the imbalance response for a rotor supported on a hybrid bearing are presented. For typical bearings characteristics, expressions yield stability thresholds practically equal to those reported by Lund (1966). The hybrid bearing design has a single injection port whose location is so chosen to stabilize the bearing performance and to reduce the steady equilibrium attitude angle. Rotordynamics coefficients graphs for conventional and pressurized bearings, as functions of bearing equilibrium eccentricity and/or Sommerfeld number, are presented. Using the rotordynamics coefficients into the expressions for the corresponding velocity thresholds and the imbalance response, the system stability and vibration performances are estimated and analyzed. When comparing the Jeffcott flexible shaft supported on two journal bearings of the conventional type with the hybrid type, the results show a clear superiority of the pressurized design as far as stability behavior is concerned. Specifically for cases of flexible shafts with similar characteristics to those used in industry, the analysis shows that this design yields velocity thresholds 25%–40% higher compared to the conventional circular ones. Also this bearing displays nonlinear feeding pressure behavior, and it is capable of reducing the synchronous vibration amplitude in most speed ranges, except around the critical speed; moreover, for certain Jeffcott configurations the amplitude reduction can be substantial.

scholarly journals Application of the IMO Second Generation Intact Stability Criteria to a Ballast-Free Containership

2021 ◽  
Vol 9 (12) ◽  
pp. 1416
Author(s):  
Nicola Petacco ◽  
Danilo Pitardi ◽  
Carlo Podenzana Bonvino ◽  
Paola Gualeni
Keyword(s):  
Sensitivity Analysis ◽  
Performance Assessment ◽  
Second Generation ◽  
Assessment Tool ◽  
Container Ship ◽  
Stability Criteria ◽  
Hull Form ◽  
Stability Performance ◽  
Intact Stability

A methodology is presented to systematically modify the hull shape of a ballast-free container ship, in order to manage the issue of righting lever variation in waves. The IMO second generation intact stability criteria have been identified as a stability performance assessment tool, while the vertical prismatic coefficient has been selected as the leading parameter of hull modifications to carry out the sensitivity analysis. A revised Lackenby procedure has been chosen to make systematic changes at the hull form. The outcomes of this investigation point out that the proposed procedure is suitable to enable the ship to be fully compliant with the IMO vulnerability levels with minor design adjustment.

Black-white contrast of dislocation loops

1978 ◽  
Vol 36 (1) ◽  
pp. 328-329
Author(s):  
J. J. Hren ◽  
W. D. Cooper ◽  
L. J. Sykes
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dislocation Loops ◽  
Major Premise ◽  
Burgers Vector ◽  
Transmission Electron ◽  
Primary Means ◽  
Contrast Analysis ◽  
Dot Product ◽  
Imaging Conditions

Small dislocation loops observed by transmission electron microscopy exhibit a characteristic black-white strain contrast when observed under dynamical imaging conditions. In many cases, the topography and orientation of the image may be used to determine the nature of the loop crystallography. Two distinct but somewhat overlapping procedures have been developed for the contrast analysis and identification of small dislocation loops. One group of investigators has emphasized the use of the topography of the image as the principle tool for analysis. The major premise of this method is that the characteristic details of the image topography are dependent only on the magnitude of the dot product between the loop Burgers vector and the diffracting vector. This technique is commonly referred to as the (g•b) analysis. A second group of investigators has emphasized the use of the orientation of the direction of black-white contrast as the primary means of analysis.

OPTIMALISASI PERAN PEMDA DALAM MENGATASI KENDALA PELAKSANAAN KONSERVASI KEANEKARAGAMAN HAYATI DI DAERAH (STUDI KASUS PROVINSI BENGKULU)

2020 ◽  
Vol 15 (2) ◽  
Author(s):  
Antung Deddy Radiansyah
Keyword(s):  
Local Government ◽  
Biodiversity Conservation ◽  
Local Governments ◽  
Central Government ◽  
Wild Plants ◽  
Regional Government ◽  
Conservation Areas ◽  
Conservation Area ◽  
Conservation Policies

Gaps in biodiversity conservation management within the Conservation Area that are the responsibility of the central government and outside the Conservation Areas or as the Essential Ecosystems Area (EEA) which are the authority of the Regional Government, have caused various spatial conflicts between wildlife /wild plants and land management activities. Several obstacles faced by the Local Government to conduct its authority to manage (EEA), caused the number and area of EEA determined by the Local Government to be still low. At present only 703,000 ha are determined from the 67 million ha indicated by EEA. This study aims to overview biodiversity conservation policies by local governments and company perceptions in implementing conservation policies and formulate strategies for optimizing the role of Local Governments. From the results of this study, there has not been found any legal umbrella for the implementation of Law number 23/ 2014 related to the conservation of important ecosystems in the regions. This regulatory vacuum leaves the local government in a dilemma for continuing various conservation programs. By using a SWOT to the internal strategic environment and external stratetegic environment of the Environment and Forestry Service, Bengkulu Province , as well as using an analysis of company perceptions of the conservation policies regulatary , this study has been formulated a “survival strategy” through collaboration between the Central Government, Local Governments and the Private Sector to optimize the role of Local Government’s to establish EEA in the regions.Keywords: Management gaps, Essential Ecosystems Area (EEA), Conservation Areas, SWOT analysis and perception analysis

Faiza Ambah's Mariam and the Embodied Politics of Veiling in France

Paragraph ◽  
2019 ◽  
Vol 42 (3) ◽  
pp. 333-350
Author(s):  
Kaya Davies Hayon
Keyword(s):  
The West ◽  
Everyday Lives ◽  
Embodied Experiences ◽  
Primary Means ◽  
The Veil ◽  
Islam And Secularism ◽  
The Impact

This article argues that Mariam uses its eponymous heroine's lived and embodied experiences of veiling to explore the impact of French secular legislation on Muslim schoolgirls' everyday lives in France. Interweaving secularism studies, feminism and phenomenology, I argue that the film portrays the headscarf as the primary means by which its protagonist is able to resist male patriarchal authority and negotiate her hybrid subjectivity. I conclude that Mariam offers a nuanced representation of veiling that troubles the perceived distinctions between Islam and secularism, oppression and freedom, and the veil and feminism in France and the West.

Pescadores migrantes: análisis de su dinámica e integración Social

2019 ◽  
Vol 37 (3) ◽  
pp. 18
Author(s):  
Fernando González Laxe
Keyword(s):  
Renewable Resources ◽  
Sustainable Management ◽  
Social Groups ◽  
Technological Innovations ◽  
Social Competition ◽  
Factors Affecting ◽  
Fish Stocks ◽  
Fishery Resources ◽  
Migration Dynamics ◽  
The Many

The globalization of the economy encourages massive population displacements and inevitably generates a cosmopolitization of societies. This leads to concern, misunderstanding and rejection. The most vulnerable social groups in society can perceive the population as intruders and enemies in social competition. Undoubtedly, the extreme spatial instability of fishery resources is among the many factors affecting migration dynamics. Various reasons for the mobility of fishermen are relevant around this concept. These include aspect related to traditions, to the capitalisation of activity, to technological innovations, and to innovation exchanges concerning the location of fish stocks. This article reflects on spatial increase of fishermen’s. The analyse are part of the paradigm of the sustainable management of common renewable resources, in particular fishery resources. It presents three lines of analysis: the reason for mobility; the choice of destination; and are the integration into host units.

Sign in / Sign up

Export Citation Format

Share Document