The profitability of the artisanal galician fleet

A large artisanal fleet made up of small-sized vessels fishes along the Galician coastline using passive gear and traps. The aim of this study is to analyse the economic profitability of this fleet in the last 5 years by looking at the average rate of return on the vessel and the investment payback period. The results show a slight drop in the return per vessel half-way through the period studied caused by the effects of the Prestige oil spill, to quickly recover over the following 2 years. Considerably high profitability rates from fishing activity were observed, especially in the second half of the period, and slightly lower payback periods, in general, than the average life of a standard fleet vessel.     

The profitability of the Spanish swordfish fleet in the North Atlantic

Our aim is to analyse the profitability of the Spanish swordfish fleet in the North Atlantic on the basis of the estimate of the gross profit per standard vessel, the average yield and the investment payback period (PP). The swordfish fleet has grown over the last decade to become the main producer in this fishery and one of the most stable fleets of all the Spanish fisheries. The results obtained show increases in profit per vessel, although there was a slight decrease in the final year studied, relatively high rates of return and PP shorter than the average life of one of the fleet's standard vessels.     

Is the Spanish Greenland halibut fleet profitable after introducing the biological recovery plan?

The aim of this study is to analyse the economic profitability of the Spanish Greenland halibut fleet in waters of the northwest Atlantic after the introduction of the halibut recovery plan. For it, the average yield and the investment payback period are used in the analysis. The results show a slight reduction in the average yield per vessel, especially at the end of the period and after the introduction of the halibut recovery plan, but with fishing profitability rates considerably high and payback periods slightly lower, in general, than the average life of a standard fleet vessel.     

Unmanned Underwater Vehicle Fuel Cell Energy/Power System Technology Assessment

This paper provides a technology assessment for an unmanned underwater vehicle (UUV) fuel cell energy/power system (FCEPS), including design methodology and design concepts. The design concepts are based on the polymer electrolyte membrane fuel cell (FC) operating on hydrogen and oxygen. The technology assessment method presented is a holistic approach which combines alternative hydrogen and oxygen storage [and fuel cell system (FCS)] options to provide the highest specific energy and energy density-within the constraints of the UUV application. Using this method, some surprising combinations appear as the theoretical ldquowinnersrdquo for maximum energy storage within the application constraints of the UUV.     

Strategies for promoting biodiesel use in marine vessels

The marine transportation sector, responsible for consuming a large amount of degraded fuel oil, is one of the major contributors to global warming and air pollution. These effects are responsible for a large number of premature deaths in the US and throughout the world. The international regulation known as the 2008 MARPOL Annex VI Amendment, which is enforced by the International Maritime Organization (IMO), has imposed progressively more stringent limits on emissions from marine vessels. Biodiesel, an environmentally friendly, renewable, clean, and low-carbon fuel, is regarded as the most appropriate alternative fuel for marine vessels. However, the promotion of biodiesel use in water-borne transportation is considered to be a bigger challenge than its more successful development in land-based applications. The major obstacles to promoting biodiesel blends in marine transportation are examined in this study. The strategies proposed to overcome these obstacles include the comprehensive field testing of the biodiesel blends in marine vessels of various representative types, establishing a marine-grade biodiesel specification, increasing the price competitiveness of marine-grade biodiesel by reducing its manufacturing costs, providing tax cuts, exemptions, and government subsidies, increasing the amount of biodiesel use in marine applications, adopting compatible elastomers and metallic materials in fuel feeding systems and storage tanks, applying approaches or technologies suitable for improving the low-temperature fluidity of biodiesel blends, and increasing the added value of purified glycerol. The effective application of these strategies will enable the more widespread use of biodiesel in marine applications, significantly reducing emissions from ships, improving global air quality, protecting the ecological environment and improving people’s health.     

Parametric analysis of the configuration of autonomous underwatervehicles

The design of an autonomous underwater vehicle (AUV) involves complex tradeoffs among various design variables and mission requirements. Particularly important are the selection of a suitable energy source and the sensitivity of vehicle dimensional characteristics to mission requirements. A method of comparison based on an approximate but comprehensive approach which refers to specific parameters derivable from known designs or literature is suggested. Specific energy and energy density of candidate systems are derived with due consideration to depth-resistant vessels. The impact of the energy system choice is highlighted, going beyond simply comparing the former parameters. A design model has been developed, allowing quick sensitivity and mass-volume breakdown of alternative configurations under varying mission requirements; these are exemplified with reference to a design case. The procedure allows the correct specification of power, energy, and surface-handling systems for more detailed comparative analyses, given a common project goal and a basis for realistic cost comparison. The results show wide differences in the energy capacity of AUVs complying with identical mission data, but using with different energy systems. It is concluded that rechargeable electric batteries, even of high energy density, result in unacceptably heavy vehicles for ranges around 1000 km unless very low drag characteristics are achieved. Closed-cycle diesel and fuel cell systems allow the AUV mass to be kept below 10 t     

Rapid decrease in Antarctic sea ice in recent years

A 41-year Antarctic sea ice concentration(SIC) dataset derived from satellite passive microwave radiometers during the period of 1979–2019 has been used to analyze sea ice changes in recent decades. The trends of SIC and sea ice extent(SIE) are calculated during the periods of 1979–2019, 1979–2013, and 2014–2019. The trends show regionally dependent features. The SIC shows an increasing trend in most of the regions except the Bellingshausen Sea and Amundsen Sea(BA) during 1979–2019 and 1979–2013. The SIE trend shows a decreasing or decelerating trend in the period of 1979–2019((6 835±2 210) km2/a) compared with the 1979–2013 period((18 600±2 203) km~2/a). In recent years(2014–2019), the SIC and SIE have exhibited decreasing trends(–(34 567±3 521) km~2/month), especially in the Weddell Sea(WS) and Ross Sea(RS) during summer and autumn. The trends are related to regionally dependent causes. The analyses show that the SIC and SIE decreased in response to the warming trend of 2 m air temperature(T_(a-2m)) and have exhibited a good relationship with T_(a-2m) in summer and autumn in recent years. The sea ice decrease in the Antarctic is mainly caused by increases in absorbed energy and southward energy transportation in recent years, such as the increase in gained solar radiation and moist static energy from the south, which demonstrate notable regional characteristics. In the WS region, the local positive feedback from the additional absorbed solar radiation, resulting in warmer air and reduced sea ice, is the main reason for the sea ice decrease in recent years. The increase in southward energy transport has also favored a decrease in sea ice. In the RS region, the increase in southward-transported moist static energy has contributed to the decrease in sea ice, and the increases in cloud cover and longwave radiation have prevented sea ice growth.     

石油降解菌对石油烃的降解能力及影响因素研究

采取油浓度梯度升高的方法,从胜利油田石油污染土壤中富集分离出以柴油为碳源和能源的优势除油混合菌B4。混合菌中分离出7株可培养菌。混合菌在含油0.5%的无机盐液体培养基中培养7天后柴油的去除率达到90.4%。该菌有较好的耐受性,当盐度达3.5时,油浓度达1.0%,亦有较好长势。混合菌对油污染土壤的修复有较好的效果,特别是加入营养盐,降解率达85.6%。混合菌脱氢酶动态变化的初步研究结果表明微生物活性变化与降解率有很好的相关性。     

Design of Mooring System for Oil Storage Vessels

The floating oil storage system has been proposed as a new facility for Strategic Petroleum Reserve (SPR) in China. Mooring is one of the key technologies to ensure the safety, reliability, and performance of the oil storage system. This paper describes the concept, analysis, design and reliability of the mooring system. For mooring system design of these oil vessels, analysis is essential of the behavior of the vessel in connection with mooring facilities of nonlinear resilience. A nonlinear mathematical model for analyzing a moored vessel is established and solved. Some results of numerical simulations are presented. Assessment of the safety regarding the mooring system in terms of failure probability is carried out. Another simulation model for calculating the failure probability of the mooring system is proposed. The design parameters that have an influence on the characteristics of the failure probability have been identified. The simulation results show that the mooring system has an annual reliab     

Testing and evaluation of GFRP composite deck panels

Fiber reinforced polymer composite deck panels are effectively used in the construction of offshore structures such as pontoons, floating docks, oil drilling platforms, ocean thermal energy conversion (OTEC) systems and harbor structures due to their excellent corrosion and fatigue resistance, high strength to weight ratio and stiffness to weight ratio and less maintenance cost. The main objective of this investigation is to study the load–deflection behavior of glass fiber reinforced polymer (GFRP) composite deck panels under static loading. Three prototype GFRP composite deck panels each with a size of 3000 mm×1000 mm×300 mm were fabricated using hand lay-up process and tested under a factored load of AASHTO HS20/IRC Class A wheeled vehicle. The deck panels were analyzed using the standard FE software, ANSYS. Maximum deflection and strain at factored load, and flexural and shear rigidities were calculated in the FE analysis and compared with the experimental data, and also with the specifications given by the Ohio Department of Transportation (ODOT), USA. From this study, it is concluded that the fabricated GFRP deck panels satisfied the performance criteria specified by ODOT and can be used in berthing structures, bridges in coastal regions, offshore oil platforms, OTEC systems and also in seismic prone areas.     

Investigation of strategies to improve the recycling effectiveness of waste oil from fishing vessels

The marine ecological environment and fishery resources can be severely polluted or destroyed by waste oil from fishing vessels if they are emitted directly into the ocean without any proper pre-treatment process. International conventions such as MARPOL 73/78 regulate waste-oil emissions and require the installation of a waste oil–water separator only for ocean-going ships of over 400 gross tons. Hence, these international conventions are not applicable to most fishing ships due to their low gross tonnages. In addition, space on most fishing vessels is too limited to allow waste-oil storage tanks or a waste oil-water separator to comply with international maritime regulations. Because a significant amount of waste oil is produced by fishing vessels around the world every day, effective strategies or measures are needed to prevent this waste oil from polluting the marine environment. This study thus investigates strategies and measures for improving the effectiveness of waste-oil collection from fishing vessels. This study found that existing procedures for the collection and treatment of waste lubricating oil on land could be applied to the management of waste oil and bilge water from fishing vessels. Sufficient oil–water separators and storage facilities for the collection of waste oil should be placed at each fishing port and shipyard. Fishermen should then be required to deliver their waste oil to these storage facilities, from where it can be transported to legal recycling companies for further treatment. In addition, fishing harbor authorities should bear definitive responsibility for monitoring the illegal dumping of waste oil and for checking the waste-oil record books of fishing vessels. Each maritime country should enforce relevant laws and regulations to reduce the emission of waste oil from fishing vessels into the ocean.     

中国石化原油多元化国际投资战略研究

2010年我国进口原油2．39亿吨,原油对外依存度已经超过55％。截至2010年,三大石油公司的海外业务已遍及全球50多个国家和地区。中国石化海外原油产量从2008年的901万吨增长到2009年的1700万吨。在当前“走出去”的大环境下,为保证我国的能源安全,中国石化也在积极寻求海外油源多元化投资。中国石化海外油源投资应主要关注石油储量和产量排名前三十名的国家,包括亚太国家7个,非洲国家6个,中东国家7个,欧洲和西半球国家10个。根据政治、储量、技术、经济和环保五类风险的分析结果,优选地区排序依次为中东、非洲、南美、亚太和中亚。在海外油源国投资时,针对政治、经济、管理、技术和自然环境风险,应采取与当地国际石油公司加强合作、认真分析当地法律政策、进行资产管理分散风险、加大科技研发投入、加强安全培训等方法。中国石化在未来油源国际化投资的发展战略中,应加大上游投入,发挥自身优势与国际石油公司合作共赢,并且在国际上游投资难度不断加大的情况下,大胆采取与境外公司并购的方式获取油源。     

Effects of the fuel price crisis on the energy efficiency and the economic performance of the European Union fishing fleets

Recent fuel price increases, together with future scarcity of fossil fuels and pollution have raised awareness about the efficient use of energy. Expenditure on marine fuel represents a significant component of the operational costs of the fishing fleets and, as a result, the profitability of the fishing fleets is very sensitive to fuel price variations. By assembling data from 54 fishing fleets around Europe, representing one fourth of the European Union (EU) fishing fleet in terms of vessel numbers and one third in terms of the volume of landings, the effects of the fuel price increase on the economic performance and the energy efficiency of the EU fleet, were estimated for the period 2002–2008. Results demonstrate declining trends in the economic indicators through the years, with a 33% reduction in profitability of the fleets since the beginning of the study. Most energy efficiency indicators, which featured a deteriorating trend over time, have improved their performance after 2004, when the first fuel price increase of the period was observed. However, results do vary across fleet segments.     

Influence of submersion season on the development of test panel biofouling communities in a tropical coast

The effect of test panel submersion season on the colonization of biofouling communities in a tropical coast revealed that the effects of panel submersion time should be taken into consideration for modelling fouling community recruitment dynamics in coastal systems or during the field trials of antifouling coatings. Wooden test panels fitted onto a raft were submerged during pre-monsoon, monsoon and post-monsoon seasons for the development of the biofouling community. Results showed considerable variation in the colonization of fouling communities on test panels submerged during different seasons. Barnacles, tubeworms, ascidians and seaweeds were the major fouling communities that colonized the test panels. The total biomass of the fouling communities that settled on the post-monsoon season panels varied from the initial value of 2.72 g dm⁻² to a maximum of 44.5 g dm⁻². On the panels submerged during monsoon season, the total biomass of fouling communities varied between 0.78 g dm⁻² and 69.9 g dm⁻². The total fouling biomass on the pre-monsoon season panels varied between 2.95 and 33.5 g dm⁻². Barnacles were the initial colonizers on the panels submerged during pre-monsoon and post-monsoon seasons. Soft-bodied organisms such as ascidians dominated the monsoon season-initiated panel series during the initial period.     

Review of challenges in reliable electric power delivery to remote deep water enhanced oil recovery systems

This paper reviews the major challenges involved in reliable electric power delivery to remote deep water enhanced oil recovery (EOR) systems. As the oil well matures, top side based booster systems are not economical, and hence, subsea based booster systems are required. Such EOR processes require subsea systems to be operated at varying power and voltage levels, and this requires establishing subsea power stations with long tiebacks from the shore. Subsea stations carry out safe voltage step-down, distribution and conversion of electrical power in the order of mega watts. Breakdowns in subsea based EOR systems lead to huge production losses, and system retrieval for repair and maintenance is very costly and time consuming, and therefore systems need to be highly reliable. This paper describes the technical challenges involved in subsea variable speed motor drives, long step out power transmission, subsea energy storage requirements for safe start up and emergency shutdown, thermal and humidity management inside pressure rated enclosures, fault localization, pressure tolerant electronics and bio-fouling. Emerging advancements in electrical, power electronic, power transmission, energy storage and packaging technologies are reviewed, giving the confidence that the present technical maturity would be able to drive the development of reliable subsea based EOR systems.     

Some dynamics of spilled oil in a fractured ice field in Buzzards Bay, Massachusetts

A spill of #2 fuel oil occurred 28 January 1977 in a dynamic ice field in BBuzzards Bay, Massachusetts. An oil budget study revealed that within four days after the spill occurred, approximately 60% of the oil was incorporated into the fractured ice zones and onto the ice surface. The movement of the oil (initially spilled under the ice) into the fracture zones appears to be the result of water current below the ice and buoyancy spreading mechanisms. Areas of fracture zones and leads provided a surface outlet for the less dense oil as it moved under the ice. When the leads closed, the oil was trapped into tools on top of the ice at the floe edges. The further spread of the oil onto the surface of the ice floes appears to have been caused by the wind.     

多船旁靠系泊作业关键特性试验研究

旁靠带缆作业是实现海上补给、模块吊运、原油外输等运转的常用方式,针对浮式平台与两艘供应船以旁靠方式作业涉及的关键特征进行水池模型试验研究,阐述了旁靠带缆系统和护舷设备的属性和需遵循的规范衡准,深入分析旁靠系缆的张力、护舷的挤压力、船体之间的相对运动特征随有效波高和波浪入射角度等环境参数的变化规律,确定了适用于多船旁靠作业的海况条件。研究表明:波浪能量随有效波高的增大呈现非线性增大趋势,是影响旁靠作业窗口期的主要外部因素,而波浪入射角度对旁靠作业的影响程度与海况有较大关系;三船在纵荡、横荡以及艏摇方向具有明显的跟随性特点,运动响应的幅值和相位比较接近,浮式平台与供应船之间的相对运动较小,完全可满足作业要求。垂荡、横摇以及纵摇这三个波频方向,各船的运动并不同步,相对运动大,是影响多船旁靠作业窗口期的主要因素;有效波高为2.5 m的海况条件可满足多船旁靠要求。相关结论为实际的工程操作提供参考。     

Numerical evaluation of a subsea equipment installation method designed to avoid resonant responses

Several methods have been employed to install the different types of subsea equipment that are required for offshore oil and gas production systems. More recently, the increasing development of oil fields at remote, ultra-deepwater scenarios has been requiring heavier and more complex subsea equipment. In such scenarios the usual installation methods have been facing increasing challenges, including resonance effects associated to the dynamic behavior of the cable-equipment system. In this context, after presenting a review of the state-of-the-art of installation methods for subsea equipment, this work presents a methodology for the design and evaluation of an installation method based on the combination of steel wire and polyester ropes. The goal is to obtain a feasible and safe installation method that can avoid resonance effects along all phases of the lowering procedure, without the need of specialized devices such as heave compensators, and using only simpler installation vessels such as standard tugboats instead of more expensive and specialized vessels (such as drilling rigs). The method is evaluated by numerical simulations for case studies considering representative metocean data for Brazilian ultra-deepwater scenarios, following a methodology that considers the random characteristic of actual sea states by employing an irregular spectral representation. The results indicate that the method may indeed be feasible for the deepwater installation of heavier equipment, potentially being more cost-effective especially for remote locations where other more complex methods might become inefficient.     

The social cost of fishery subsidy reforms

This paper analyzes the impact of reducing fisheries subsidies in a general equilibrium model for a fishery with heterogeneous vessels. It considers the impact of the stock effect, which determines the participation of vessels in a likely increased stock abundance. In equilibrium, the productivity of the fleet is endogenous as it depends on the stock of fish along the equilibrium path. The model concludes that any impact of a subsidy drop will depend on the stock effect. If that effect is large, fishing firms will benefit from the stock recovery and the elimination of the subsidy will increase future returns on investment. The model is particularised to industrial shrimp fisheries in Mexico. It is shown that the complete elimination of a subsidy increases biomass, capitalisation, marginal productivity, and consumption and reduces inequality when the effect of the induced increase in the stock is considered. However, if that effect is not considered, capital and consumption decrease, and inequality and hence, the social costs of a subsidy drop, increase.     

深海能源开发现状和前景研究

走向深海大洋、探测深海环境和获取深海能源对未来国家能源战略开发至关重要。文章借助相关历史数据,回顾包括石油和天然气、天然气水合物以及可再生能源在内的深海能源的开发历史;阐述在技术、投资和全球经济环境驱动下的深海能源开发现状,即技术和产业不断发展、合作和投资亮点频出以及开发重点随全球经济变化而调整;在此基础上,分别对主要深海能源的发展前景进行展望,即石油开发步伐放缓、天然气迎来发展高峰、天然气水合物规模化商业开采有待观察以及可再生能源获得更多关注和投资。