Oil Outflow Research Articles

Reduction in Adsorption of Bearing Oil From Fluid Dynamic Bearings of Hard Disk Drive Spindle Motor by Diamagnetism

In this study, we focused on the diamagnetism of ester lubricant oil for fluid dynamic bearings (FDBs) and investigated the effect of a magnetic field on oil vapors. We vaporized the lubricant oil and compared the amount of oil adsorbed on disk surfaces through two slits-one with magnets and the other without a magnet-in a preliminary experiment. As a result, we confirmed that it is possible to reduce the amount of oil adsorbed on a disk surface with the aid of a magnetic field. Based on the preliminary experiment, the outflow of the FDB oil from the hard disk drive (HDD) spindle was compared with regard to a narrow clearance with and without the magnetic field gradient of permanent magnets. The amount of outflow was decreased by the magnetic field gradient, and the reduction ratio depended on the environmental temperature. Finally, our results suggest the possibility of a gas seal generated by the magnetic field gradient.

An investigation on cost-effective tanker design configurations for reduced oil outflow

This paper reports on an investigation of the cost-effectiveness of selected design risk control options considered for improved environmental protection from the operation of crude oil tankers. The analysis has been carried out for representative Panamax, Aframax, Suezmax and VLCC tankers and elaborates on design modifications for enhanced cargo tank subdivisions, increased double bottom height and increased side tank width with the view to establish cost-effective trade-offs between oil outflow reduction and associated life-cycle implementation costs for new-buildings. The results demonstrate the applicability of the investigated risk control options and their potential contribution to reduced oil spills.

Analytical and numerical modelling of oil spill from a side tank with collision damage

The objective of this paper is to study oil spills from damaged tanks during ship collision. The work comprises development of analytic models for estimation of oil spill and computational fluid dynamics (CFD) simulation with the Fluent software for verification of the simple models. In previous papers, oil leakage from a damaged tank with an opening in the bottom was investigated. The purpose of the present study is to extend the scope to cover oil spills for the case of collisions where the openings occur in the sides. In such cases, the gravitational force is very important as for the grounding scenario. However, for collision scenarios, there is a local imbalance due to different densities of the fluids even when the internal pressure is equal to the external pressure. A combination of water inflow and oil outflow through the opening may occur. Analytical calculations and time-domain simulations are applied to calculate the volume of oil outflow and the outflow rate versus time. Good agreement is obtained between the analytic model and the CFD analysis of the oil spill.

Multi-Objective Optimization Design of Tanker Ships via a Genetic Algorithm

The cost of a new ship design heavily depends on the principal dimensions of the ship; however, dimensions minimization often conflicts with the minimum oil outflow (in the event of an accidental spill). This study demonstrates one rational methodology for selecting the optimal dimensions and coefficients of form of tankers via the use of a genetic algorithm. Therein, a multi-objective optimization problem was formulated by using two objective attributes in the evaluation of each design, specifically, total cost and mean oil outflow. In addition, a procedure that can be used to balance the designs in terms of weight and useful space is proposed. A genetic algorithm was implemented to search for optimal design parameters and to identify the nondominated Pareto frontier. At the end of this study, three real ships are used as case studies.

An oil outflow model for tanker collisions and groundings

In this paper we have developed an oil outflow model for collision and grounding accidents of tankers. The collision model explicitly links input variables such as tanker hull design (single or double), displacement and speed, striking vessel displacement and speed, and the interaction angle of both vessels to output variables: longitudinal and transversal damage extents of the tanker. Overlaying these damage extents on the tank vessel’s design yields an oil outflow volume totaling the capacity of the damaged tank compartments. A similar model is developed for grounding accidents. A total of 80,000 simulation accident scenarios described in the National Research Council SR259 report published in 2001 served as the joint data set of input and output variables used in this “linking” process. The oil outflow model herein was designed keeping computational efficiency in mind to allow for its integration with a maritime transportation system (MTS) simulation. We shall demonstrate the use of the oil outflow model as a final analysis layer to evaluate double-hull effectiveness in a geographic context of an MTS simulation model developed for the oil transportation routes traversing the environmentally sensitive San Juan Islands area in Washington State.

Performance of Buffer Bow Structure against Collision—On the Effect in Preventing Oil Outflow

The critical striking velocity (VBcr) and the critical collision angle (θcr) are introduced as the measures to represent the performance level of buffer bow. Those critical events are defined as the threshold whether the inner hull of struck tanker is ruptured or not, and they are determined through a series of finite element method (FEM) simulation analyses. Then the effectiveness of buffer bow is highlighted by focusing on the performance how much the risk of oil outflow is decreased. The risk of oil outflow is represented by "the mean oil outflow," which is derived based on a probabilistic procedure considering possible dangerous collision scenarios. The case study has shown that the probabilistic oil outflow is decreased by about 80% if buffer bow design is adopted to very large crude carrier (VLCC).

Calculation of oil outflow from fuel oil tanks of a containership with polymer coatings applied to double bottom tanks — in the light of Resolution MEPC. 141(54) of IMO

Calculation of oil outflow from fuel oil tanks of a containership with polymer coatings applied to double bottom tanks — in the light of Resolution MEPC. 141(54) of IMO Introduction of the semi-elastic barrier into fuel tanks rise environmental protection level in case of ship collision or grounding. Last law regulations requires change of localisation of fuel tanks in ship structure in a such way to increasing distance between fuel and surounding water. Application of semielastic barrier into fuel tank make possible to localise fuel tanks in double bottomspace. Calculation of hipothetical outflow of fuel from damaged fuel tan in case of application of senielastic barier is presented.

Study on side structure resistance to ship-ship collisions

Double hull (DH) tankers may be more effective than single hull (SH) tankers in pollution prevention because they have a second barrier, the inner skin, to oil outflow in the event of side damage. The actual effect of DHs calls for quantitative study. This paper presents a comparative study on the side structure resistance to collisions. A DH Aframax tanker and an SH Aframax tanker of similar size were selected for the study. The two vessels were assumed to be struck by a same bulbous bow in different locations and angles. The bow was assumed to be rigid and different non-linear materials and contact models were considered for the struck tankers based on the original designs. The DH tanker was found to be superior to the SH tanker in relation to resistance to side structural damage. Finally, by using the simulation results, the distribution of damage extents for DH tankers is proposed based on the historical damage extents, which are mainly for SH tankers.

MODEL FOR PROBABILISTIC ASSESSMENT OF OIL OUTFLOW EVENT CAUSED BY TANKER ACCIDENT

Model proposed in this paper can be used to predict oil outflow event, caused by the tanker accident, probability distribution in different sectors of navigation area. The use of expert judgment techniques to obtain necessary data for application of the model ensures that all relevant available information (world and regional marine accident statistics, factors inherent to navigational area in question) will be duly taken into account. Model is designed for the Lithuanian responsibility sea area; the assessment of probability of oil outflow event and its distribution in different sectors of the area is performed.

ESTIMATION OF EXPECTED CARGO OIL OUTFLOW FROM TANKER INVOLVED IN CASUALTY

Modified version of simplified probabilistic methodology, designed for estimation of expected cargo oil outflow from tanker involved in casualty, is proposed. Suggested modified methodology can be used in the circumstances, when only very limited initial input data about the incident and tanker design is available. When applied in certain sea region (for example in Lithuanian sector of the Baltic Sea area), proposed methodology can be used in extremely short time spans, ‐ estimation procedure requires several times less time than standard IMO methodologies, and gives quite insignificant errors of estimated oil outflow.

Solving a gas-lift optimization problem by dynamic programming

Gas lift is a costly, however indispensable means to recover oil from high-depth reservoirs that entails solving the gas-lift optimization problem, GOP, often in response to variations in the dynamics of the reservoir and economic oscillations. GOP can be cast as a mixed integer nonlinear programming problem whose integer variables decide which oil wells should produce, while the continuous variables allocate the gas-compressing capacity to the active ones. This paper extends the GOP formulation to encompass uncertainties in the oil outflow and precedence constraints imposed on the activation of wells. Recursive solutions are suggested for instances devoid of precedence constraints, as well as instances arising from precedence constraints induced by forests and general acyclic graphs. For the first two classes, pseudo-polynomial algorithms are developed to solve a discretized version of GOP, while the most general version is shown to be NP-Hard in the strong sense. Numerical experiments provide evidence that the approximate algorithms obtained by solving the recurrences produce near-optimal solutions. Further, the family of cover inequalities of the knapsack problem is extended to the gas-lift optimization problem.

A comparative study of numerical simulations for fluid–structure interaction of liquid-filled tank during ship collision

Although International Maritime Organization (IMO) has taken many measures to minimize ship collisions, ships carrying liquid cargo sometimes do get struck by other vessels. The outflow of crude oil causes very serious consequences to the environment. In such cases it is necessary to analyze the response of structure of struck liquid cargo-filled tank to account for fluid–structure interaction accurately. In this paper, numerical simulation of collision between a container ship with double hull very large crude carrier (VLCC) is presented. Three different numerical simulation mothods were adopted to model fluid–structure interaction in liquid-filled cargo tank, namely arbitrary Lagrangian–Eulerian finite element method, Lagrangian finite element method and linear sloshing model. The numerical simulation results reveal that the fluid–structure interaction of liquid cargo-filled tank has a significant effect on the motion and structural response of the struck cargo tank. Compared with the calculation results of ALE FE method, the linear sloshing model underestimates the influence of fluid–structure interaction of liquid cargo tank while the Lagrangian–Eulerian finite element method may be considered as the practical method for engineering applications as it provided more reasonable results with a relatively low central processing unit (CPU) time.

Numerical simulation of fluid–structure interaction of liquid cargo filled tank during ship collision using the ALE finite element method

Ships carrying liquid cargo are sometimes unavoidably struck by other vessels. Since the outflow of crude oil will have very serious consequences on the environment, it is necessary to accurately evaluate fluid–structure interaction of liquid cargo filled tank. The arbitrary Lagrangian—Eulerian (ALE) finite element method solves the transient equations of motion of the fluid and structure using the explicit time integration method and is suitable to analyse highly dynamic, highly non-linear phenomena lasting for a short time. The ALE finite element method is validated by the hydrodynamic impact of drop box experiment. A numerical simulation procedure for a ship collision between a 72,000 tons container ship and a crude oil cargo tank of a 293,000 tons double hull VLCC taking account of the fluid–structure interaction is presented. The numerical simulation results reveal that the fluid–structure interaction of liquid cargo filled tank has a remarkable effect on the motion and structural response of the struck cargo tank.

4812 ピストンリング合口部からのオイル上がりに関する研究(G07-2 エンジンシステム(2),G07 エンジンシステム)

Oil consumption is caused by the evaporation of oil film left on the cylinder wall or by the combustion of oil flowing out to the combustion camber through the piston ring gap. This study focusedd on oil outflow through the piston ring gap under a high vacuum operating condition in the intake manifold. Moreover, the oil film was visualized to determine oil film thickness. As a result, the oil flowed out steadily from the piston ring gaps at this operating condition, and moved through the surface of the top land to the combustion chamber. It was also found that the amount of oil outflow and the oil consumption were affected by the end gap design of the top ring.

Visualization System for Viscous Fluid Movement in High-pressure Vessel

Oil outflows from sunken ships, e.g., the Nakhodka and Chikubu-maru, have been reported in recent years. The purposes of this study were observation of C heavy oil gushing out behavior in freshwater and seawater at atmospheric pressure and construction of its visualization system in a high-pressure vessel which can pressurize water up to 40 MPa.One motion of C heavy oil gushing out was continuously belt-like, and the other motion was intermittently spherical. Outflows in seawater were bigger than those in freshwater.The visualization system for viscous fluid gushing out behaivior consisted of a color CCD camera, LED, and stepping motor. The system successfully recorded intermittent spherical gushing in the vessel. The oil from a sunken ship would not cause a big outflow unless the sunken body sustained a large shock or earthquake.

The International Political Economy of Oil and its Implications for the Niger Delta Crisis

The paper analyzes the international political economy of oil and deduces implications for the Niger Delta crisis. The economic analysis focuses 0n the essential nature of oil, key players, and the organization of the global industry while the analysis of the international politics of oil focuses Oil the institutions, incentives, and the dynamic games of oil. The main conclusions are that the international political economy of oil is willfully designed by established global players to guarantee a stable outflow of cheap oil to fuel a wide range of economic, social. and political activities ill rich countries. Therefore, the contest for control over the economic rents from oil cannot be domesticated and in the absence of a strong and developmental state, the social costs for oil communities would tend to grow beyond the thresholds for open conflict, yet open conflicts will not achieve the desires of the population in the Niger Delta.

IS TAMOXIFEN A RISK FACTOR FOR RETINAL VASO-OCCLUSIVE DISEASE?

Brief Reports SD, 32.7 ⫾ 4.92 years). All patients had no history of glaucoma or ocular hypertension before silicone oil tamponade. Ocular hypertension was defined as in- traocular pressure (IOP) of ⱖ21 mmHg. Sixteen pa- tients were aphakic, and three patients had compli- cated cataract. The predisposing diseases (reasons for silicone oil tamponade) were traumatic proliferative vitreoretinopathy in 17 cases and rhegmatogenous ret- inal detachment in 2 cases. Acri-Sil-ol 5000 (Acri-tec, Germany) with high viscosity was used for silicone oil tamponade. TREATMENT OF GLAUCOMA SECONDARY TO SILICONE OIL RETENTION X.F. LIN, MD, L.Y. LIANG, M.K. LIN, MD, Z.H. YUAN From Zhongshan Ophthalmic Center, Guangzhou, Guangdong Province, China. Nineteen eyes with secondary glaucoma due to sili- cone oil retention after silicone oil removal are de- scribed. The mean intraocular pressure ⫾ SD was 37.23 ⫾ 6.47 mmHg 7.89 ⫾ 2.75 days after silicone oil removal. In 5 eyes, medical therapy was effective to control intraocular pressure, while the other 14 eyes needed surgery. Cibis was the first to adopt silicone oil in the treat- ment of retinal detachment in 1962. With the rapid development of complicated posterior segment surger- ies, the use of silicone oil has increased, thus greatly improving the prognosis of proliferative vitreoreti- nopathy. However, silicone oil–related complications have also appeared. For example, retention of silicone oil after its removal may lead to secondary glaucoma, which is often overlooked and leads to the adverse consequence of delaying treatment. To study clinical features and to evaluate therapeutic efficacy, we re- viewed 19 cases (19 eyes) of secondary glaucoma due to silicone oil retention after silicone oil removal that occurred from February 2001 to May 2003. General Conditions Silicone oil removal was performed 2 months to 2.3 years (mean ⫾ SD, 17.25 ⫾ 3.16 months) after sili- cone oil tamponade. Indications for silicone oil re- moval were silicone oil emulsification (in the vitreous and anterior chamber) in 9 eyes, secondary glaucoma in 7 eyes (combined with silicone oil emulsification in 5 eyes [emulsification was detected before silicone oil removal in 3, but it was discovered during silicone oil removal in 2]), and band-shaped corneal degeneration in 4 eyes. In two cases, silicone oil removal was performed ⬎1 year after silicone oil tamponade as a result of the patients’ wishes, although no symptoms were identified. In all cases, silicone oil removal was performed via a pars plana entry. First, an infusion cannula was inserted into the vitreous cavity from an incision at the inferotemporal quarter 4.0 mm away from the limbus. Then another pars plana incision of 1.5 mm in length was made at the superotemporal quarter 4.0 mm away from the limbus. Depressing the posterior margin of the incision facilitated the silicone oil outflow. Silicone oil removal and pars plana lensectomy were done simultaneously on one eye with severe complicated cataract and silicone oil in the anterior chamber. Meanwhile, in the eyes with apha- kia and in the eye that underwent silicone oil removal and pars plana lensectomy, the contents of the anterior chamber were also replaced with balanced salt solu- tion. In the other two cases, no additional efforts were made to replace the aqueous humor, because no ob- Patients and Methods Patients Of 19 patients, 17 were males and 2 were females; their ages ranged from 15 to 47 years (mean age ⫾ The authors have no financial or proprietary interest in the study. Reprint requests: Dr. X.F. Lin, Zhongshan Ophthalmic Center, Xian Lie Nan Road 54, Guangzhou, Guangdong Province, China 510060; e-mail: Dragonye2002@yahoo.com.cn RETINA ® , The Journal of Retinal and Vitreous Diseases, encourages authors to submit Brief Reports describing unusual findings, new techniques, and new instruments. Material submitted for consideration in this section of the journal is done so with the assumption that the data provided do not duplicate previously published material and that the material has not been submitted for consideration elsewhere. Each author must sign a disclosure to this effect (see Instructions to Authors for complete wording of transfer letter). Brief Reports submitted for this section of the journal may be subjected to the standard review process that is applied to other material submitted to RETINA ® . Brief Reports should follow the requirements listed in the Instructions to Authors, with the following caveats: Brief Reports should not exceed 4 pages in length; no more than 5 references should be cited; and each Brief Report should include no more than 4 figures.

緩衝型船首構造の耐衝突性能

We still have experienced cargo oil spill from a struck D/H(double hull) tanker like the accident case of “Baltic Carrier (at Denmark in 2001)”. “Buffer Bow” has come to be considered as an innovative strategy following after D/H system to prevent marine environmental pollution. The mission expected to buffer bow is “minimizing the damage on the struck ship” and thus “decreasing the risk of oil outflow from struck D/H tankers” when it encounters collision accidents. This performance is supposed to be realized by such structural characteristics as “to be crushable” and “to have high energy capacity in the internal mechanics”. As the measures to represent the performance level of buffer bow the critical striking velocity (VB,cr) and the critical collision angle (θcr) are proposed. Those critical events are defined as the threshold where the inner hull of struck tanker is ruptured or not.As it has been confirmed in the preliminary investigation that the bulb structure is most threatening to struck ships, buffer bow design considered is focused on bulb structure. The buffer bow design items which are supposed to be effective are (1) blunt shaped configuration, (2) transverse stiffening system and (3) adopting minimum shell thickness. The advantage expected to those design items are the fact that no special equipments nor special materials are needed. Their contributions have been evaluated through a series of FEM simulation analyses adopting a VLCC as the model struck ship, and VLCC's and container ships as the threatening striking ships. The effectiveness of buffer bow is confirmed by comparing the performance of the critical striking velocity and the critical collision angle between buffer bows and standard bows.At the final stage the effect of buffer bow is evaluated by focusing on the performance that how much the risk of oil outflow is decreased. “The mean oil outflow” is derived based on probabilistic procedure considering dangerous collision scenarios. The case study has shown that the probabilistic oil outflow is decreased by about 80% if buffer bow design is adopted to VLCC.

오일 펜스 Anchor의 파주력

An oil boom was set up in order to contain diffused oil from spills and for the retrenchment of damage caused by oil Pollution. Therefore, the oil boom anchor needed proper holding power to endure high resistance from flowing streams and to secure the oil boom around the spill, and must dredge directly into the seabed when it is dropped and block oil outflow immediately. This study investigated the holding power of the danforth anchor and the coastal fishing vessel anchor used for oil booms in the KMPRC (Korea Marine Pollution Response Corporation). For each type, a 30 kg and 20 kg anchor were used. The holding power of the danforth anchors were measured by dropping both weights 10 times. However the coastal fishing vessel anchors were dropped only 5 times each, because no substantial differences were found between drops. In the results of the danforth anchors, an anchor awoke occurred in 2 drops of the 30 kg anchor and in 4 drops of the 20 kg anchor, wherein there was no holding power to be measured. With exception to the anchor awoke cases, the maximum holding power of the danforth 30 kg and 20 kg anchors was 250-520 kg and 123-233 kg, respectively. In the case of the coastal fishing vessel anchors of 30 kg and 20 kg, throughout the experiment, there was no occurrence of an anchor awoke. For the 30 kg and 20 kg anchors, the maximum holding power was measured to be 209-230 kg and 155-170 kg, respectively. Therefore, the holding power of the coastal fishing vessel anchor was shown to be much poorer than that of the danforth anchor. However, the holding power of the danforth anchor was very unstable. Due to the occurrences of anchor awoke, there was no holding power and the measurement value of maximum holding power showed too much variation among the drop tests. Also, after the maximum holding power was achieved, anchor awoke occurred easily. In the case of the coastal fishing vessel anchor was much more stabile, because there was no anchor awoke and no instance where holding power failed. Also the maximum holding power was reached quickly and almost no variation occurred among the drop tests.

Analysis of hypothetical groundings in US waters

Because grounding accidents are rare events and data is sparse, their analysis requires a probabilistic approach. This paper illustrates an analysis of a large number of hypothetical, but realistic, grounding scenarios, and the application of an approach to study the effect of design modifications on the oil outflow performance. The scenarios are sampled from initial distributions of accident factors, which define grounding events. Structural damage and resulting oil outflow is then determined for double- and single-hull designs. The effect of the double-bottom height and structural modifications on the oil outflow is investigated.