海工环境下电厂冷却系统钢筋混凝土取水暗涵设计优化

针对海工环境下电厂冷却系统钢筋混凝土取水暗涵在维修阶段出现的淤泥沉积量大、海生物大量附着、伸缩缝渗漏、嵌缝材料老化脱落、混凝土表皮开裂脱落等问题,提出了相应的设计优化和工程改造措施。实践表明,经改造后的取水暗涵基本上保证了机组运行的可靠性,同时降低了维修成本。

粉煤灰砼在海工环境中的暴露试验研究

对粉煤灰砼和基准砼在海工环境条件下分别暴露3年、5年和6年期后的氯离子含量和分布、钢筋锈蚀性能、碳化性能等方面的试验数据进行分析比对,得出以下结论:粉煤灰砼中的氯含量除表层外均明显低于基准砼,且其氯含量中氯化物多分布于外层,而里层多数处于游离状态,只要保证粉煤灰砼构件有足够的钢筋保护层,则其抗钢筋锈蚀性能较基准砼强;在海工环境中粉煤灰砼的抗渗性能随着暴露期的增长优于基准砼,但碳化性能低于基准砼.

海工预应力混凝土氯离子侵蚀模型及耐久性

总结分析了国内外有关混凝土中氯离子侵入模型的研究概况,针对海工预应力混凝土结构,讨论了影响氯离子侵入预应力混凝土的各种因素.考虑混凝土与氯离子间的结合能力,建立了预应力混凝土氯离子侵入数学模型.以混凝土保护层厚度、氯离子扩散速度以及表面氯离子浓度为主要参数,运用可靠度理论,建立了海工预应力混凝土结构耐久性可靠度分析模型.分析结果表明:应力状态下,混凝土的氯离子有效扩散系数是变化的,其中混凝土的拉应力会加快氯离子的扩散,而压应力则相反;同时从耐久性分析中可知,混凝土保护层厚度对氯离子侵蚀下的PC结构耐久性影响最大,表面氯离子浓度及氯离子扩散速度次之.

海洋工程试验水池配套设备工艺设计

为加强深海试验水池的配套设备技术研究,提供功能更全面的海洋研究平台,总结了国内外试验水池发展的现状,结合三亚崖州深海科技创新平台项目的海工试验水池配套设备实例,介绍了相关设备工艺和智能化设备控制系统。

载荷作用后粉煤灰混凝土氯离子渗透性能试验研究

粉煤灰混凝土大量应用于海工混凝土结构,其耐久性对结构耐久性至关重要。海工环境下,混凝土受到载荷与氯离子的双重作用,极易出现耐久性问题。开展了载荷作用后粉煤灰混凝土氯离子渗透性能试验研究。研究结果表明:粉煤灰掺量为20%的混凝土,从初期到后期始终具有良好的抗氯离子渗透性能;粉煤灰掺量为35%和50%的混凝土,初期抗氯离子渗透性能降低,后期有所改善。研究成果可为合理设计粉煤灰掺量提供参考。

海水腐蚀下钢纤维和PVA-钢混杂纤维对混凝土力学性能影响的对比

试验研究了PVA-钢混杂纤维混凝土(PSFRC)和钢纤维混凝土(SFRC)在海水腐蚀环境下抗压强度和劈裂抗拉强度的变化规律,并对试验结果进行了对比。结果表明,腐蚀前期SFRC和PSFRC的抗压强度和劈裂抗拉强度相差不大;腐蚀后期PSFRC的抗压强度和劈裂抗拉强度均高于SFRC。

基于连通管原理的港珠澳大桥荷载试验挠度测试的应用及精度分析

以港珠澳大桥主体工程青州航道桥为实例,分别使用连通管桥梁挠度测量系统及电子水准仪对荷载试验中关键的挠度测点进行了检测,并对两种检测结果进行了比对。结果表明,连通管法及水准仪法结果高度吻合,误差均在1%以内。该结果对连通管法在桥梁荷载试验挠度检测的使用有着重要的借鉴意义。

Influence of Reclamation Works on the Marine Environment in a Semi-Enclosed Bay

The flow and seawater exchange rates have been predicted using a two-dimensional numerical model and a Lagrangian method for a semi-enclosed shallow bay where reclaiming and dredging works are scheduled. The wind effect on the flow and material transport has been emphasized, and a thirty-year mean value of wind has been considered in the numerical simulation. As a whole, even after the reclaiming and dredging are conducted, the flow pattern looks similar to the original state. However, velocity variations up to 20% to 100% appear in the vicinity of the construction area. In the case of summcr wind forcing, the seawater exchange rate increases from 71.6% to 82.9% after the reclaiming and dredging, as indicated by a particle-tracking method. On the contrary, in the case of winter wind forcing, thc seawater cxchange rate appears to be 97.2% under natural conditions but decrcases slightly to 93.2% aftcr the rcclaiming and dredging. Thus, the wind forcing plays an important role in controlling the seawater exchangc rates. The seawater cxchange rate is further improved by 15% if the dredging is simultaneously carried out with the reclaiming. This suggests that the dredging can be an effective means to mitigate the variation of flow.

Wind Wave Characteristics and Engineering Environment of the South China Sea

Wave simulation was conducted for the period 1976 to 2005 in the South China Sea （SCS） using the wave model, WAVEWATCH-III. Wave characteristics and engineering environment were studied in the region. The wind input data are from the objective reanalysis wind datasets, which assimilate meteorological data from several sources. Comparisons of significant wave heights between simulation and TOPEX/Poseidon altimeter and buoy data show a good agreement in general. By statistical analysis, the wave characteristics, such as significant wave heights, dominant wave directions, and their seasonal variations, were discussed. The largest significant wave heights are found in winter and the smallest in spring. The annual mean dominant wave direction is northeast （NE） along the southwest （SW）-NE axis, east northeast in the northwest （NW） part of SCS, and north northeast in the southeast （SE） part of SCS. The joint distributions of wave heights and wave periods （directions） were studied. The results show a single peak pattern for joint significant wave heights and periods, and a double peak pattern for joint significant wave heights and mean directions. Furthermore, the main wave extreme parameters and directional extreme values, particularly for the 100-year return period, were also investigated. The main extreme values of significant wave heights are larger in the northern part of SCS than in the south- ern part, with the maximum value occurring to the southeast of Hainan Island. The direction of large directional extreme Hs values is focus in E in the northem and middle sea areas of SCS, while the direction of those is focus in N in the southeast sea areas of SCS.

Sleep quality alterations in healthy workers at high altitude in Yushu area

During the period of reconstruction after Yushu Earthquake, a large number of sea-level or lowland workers ascended there and worked at altitudes between 3 750 m and 4 878 m which is a hypoxic environment. To investigate the sleep quality at that altitude, we performed two full polysomnographies （PSGs） in 10 volunteers, who were healthy male workers, aged 31 ：i：6.6, born and living at sea level, without experience of pre-altitude expo- sure. The assessment of subjective sleep quality was performed twice in each volunteer. The first investigations were carried out at sea level in Jinan city （pB=760 torr, 1 torr=133.322 4 Pa）. The second studies were performed at an altitude of 3 750 m （pB=416 tort） in Yushu Jiegu in the same 10 workers after they lived and worked at that alti- tude for 5 months. At sea level, workers presented a normal sleep structure and a higher oxygenation during sleep. However, as compared to sea-level sleep, at 3 750 m, workers had a shorter total sleep time （TST） （p 〈 0.001）, a longer stage 1 non-rapid eye movement （nREM） sleep （p 〈 0.05） and a shorter 3＋4 nREM and rapid eye movement （REM） sleep （p 〈 0.05） with a severe sleep hypoxemia （p 〈 0.01）. Our data suggested that sea-level workers revealed a disturbed sleep and a bad sleep quality with a significant sleep hypoxemia at altitude of 3 750 m. Strengthening the prevention and treatment are thereby sorely necessary.

Isoenzymes and soluble protein in Arthrospira from alka-line lakes in Erdos Plateau, China and in exotic species

The authors compared isoenzymes of five enzymes and soluble protein in Arthrospira platensis (A3) and A. erdosensis (A4) from alkaline lakes in Erdos Plateau, Nei Monggo (Inner Mongalia), China and exotic species of A. platensis (A1) from Chad and A. maxima (A2) from Mexico by means of polyacrylamide gel electrophoresis. The results showed that the isoenzymes of EST, POD and soluble protein were polymorphic. Monomorphism and polymorphism were found in isoenzymes of AMY, CAT and SOD, and monomorphism was found only in the introduced species. The isoenzymes and soluble protein of the local species are all polymorphic. The number of bands in these species were in the order of A3>A4>A1>A2. A2 is the most primary, A1 from Chad Lake is relatively primary, A3 and A4 are ad- vanced species in evolution. Cluster analysis showed that the relation between the two introduced species are the closest to each other, and so too are the two local ones.

The Impact of Large-Scale Reclamation on Hydro-Dynamic Environment--A Case Study of Xinghua Bay

A hydro-dynamic model is established on basis of MIKE21 FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s^(-1). On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s^(-1). The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian.

New model for deducing directional extrema based on multivariate extremum statistical theory

The parameters of principal and directional extrema in a marine environment are important in marine engineering design, especially for appropriate construction of oceanic platforms and other structures. When designing wave walls and break water structures, the orientation of the breakwater or seawall depends mainly on the direction of the strongest waves. However, the strength of the breakwater and the elevation of the seawall depend on the magnitude of the biggest wave height of the strongest waves. Thus, identification of directional extrema plays an important role in the design of wave factors. When calculating the directional extremum, different materials may require different specific computational methods, yet few theoretical studies have been conducted in this field of research. Based on multivariate extremnm statistical theory, this paper utilizes a discrete random variable to build a joint probability model compounded by a discrete random variable and a multivariate continuous random variable. Furthermore, this paper provides the first investigation on the theories and methodologies to deduce wave directional extrema. The results provide tools for both creating the calculation method of the directional extremum value and providing the rational directional extremum parameters for marine engineering design.

Induced nest spawning and artificial hatching of the fertilized eggs of mudskipper, Boleophthalmus pectinirostris

In this study, nest spawning was successfully induced by exogenous hormone injections and seawater flow stimulation, and optimum condition for hatching fertilized eggs of burrow fish mudskipper, Boleophthalmus pectinirostris, was searched. Apart from spawning inside the nests, females also spawned outside the nests. The percentages of spawned nests were 8.0% to 24.2%. Most eggs were observed adhered to the inner wall of the top half of the nest. Fertilization rates of the nest-spawned eggs varied from 17.3% to 80.8%. Females could spawn after being artificially confined inside the nests with males at ratios of 1:1 or 1:2, but the spawned eggs were not fertilized. Mean hatching rates of artificially fertilized eggs incubated in round plastic buckets were 32.7%-70.6%, and in the net cages, were 4.2%-20.5%, respectively. Mean hatching rates of nest- fertilized eggs incubated in the round plastic buckets were 33.6%-76.3%, and in the net cages, were 5.9%-25.2%. Results showed that round bucket incubation was the best way for hatching fertilized eggs of mudskipper. Keeping the hatching seawater flowing is an important way for increasing the hatching rates of the mudskipper fertilized eggs.

Evaluation of Hong Kong Convention in the Maritime Industry

The HKC （Hong Kong Convention） adopted by the IMO in 2009 is aimed at ensuring that ships, when being recycled after reaching the end of their operational lives, do not pose any unnecessary risk to human health and safety of the marine environment. The text of the ship recycling Convention was developed with input from the IMO （International Maritime Organization） Member States and relevant NGOs （Non-Governmental Organizations）, and in co-operation with the ILO （International Labor Organization） and the Parties to the Basel Convention. The Convention intends to address all the issues around ship recycling, taking into account that ships sold for scrapping may contain environmentally hazardous substances. It addresses concerns raised about the working and environmental conditions at many of the world ship recycling locations. Regulations in the new Convention cover： the design, construction, operation and preparation of ships so as to facilitate safe and environmentally sound recycling, without compromising the safety and operational efficiency of ships; the operation of ship recycling facilities in a safe and environmentally sound manner; and the establishment of an appropriate enforcement mechanism for ship recycling, incorporating certification and reporting requirements. This paper will present and discuss the evaluation of the Hong Kong Convention. Also it will discuss implementing the Hong Kong convention to improve the recycling business, highlighting the effect of the convention on the maritime industry.

A Study on the Estimation of Ship Waves Interaction with the Sloping Banks of the Channel

The problem of shore wash in environmental engineering is connected in particular with the effect of waves generated by the ships and fast speed boats. Another problem is protection of ＂Marines＂ with anchored boat against waves. Sloping banks provoke unfavorable transformation of waves. Simultaneously sloping bank is the factor which significantly complicates prediction of wave pattern in numerical analysis. The purpose of present paper is to demonstrate the results of numerical investigation of ship waves pattern in constrain water area with slope banks by panel method for non-linear ship waves calculation usually applied for ship hull perfection as routine instrument of towing tanks technology. The method initially developed for calculation of ship hull waves in inviscid infinite fluid was adapted to meet boundary conditions on slope banks. Verification of the method was done for 60-series ship in rectangular channel. Development of wave pattern generated by two ship of different types--monohull ferries and river catamaran was investigated. It was found that ship waves height significantly increased due to slopping banks comparing with case of deep water and shallow water rectangular channel.

Strategic environmental assessment in China

In the past three decades, especially in recent years, the environment has unceasingly deteriorated with rapid development of Chinese economy, and the inherent limitations of conventional project EIA have come to light. Thus, to pursue a broader course of sustainable development, the Chinese government has attached more and more importance to SEA. Strategic Environmental Assessment （SEA） is a frontier subject in the field of Environmental Impact Assessment （EIA）. This article describes the current situation of SEA in China, discusses major problems with SEA, and then recommends improvements in the system. EIA Act of the People＇s Republic of China was promulgated which explicitly provides SEA is required in regional and sector plans and programs. In order to promote comprehensive development of SEA, a lot of work has been done by SEPA. Some SEA ＂experiments＂ have been implemented, and some research has been conducted on the topic in China. But SEA as applied today in China is confronted with a host of methodological and institutional limitations. Moreover, public participation is often extremely limited, because the system restricts public participation. Policies and strategies are kept secret from the public. Most of the research has been focused on the concept, theory, and framework of SEA. Comprehensive application of SEA in China has yet to occur, and only a limited number of case studies are available. We believe SEA can be improved by the following recommendations： dividing SEA into two stages, formulating legislation to safeguard the funds for SEA, guiding actively the public to participate in SEA, completing basic data bank about SEA, and setting up Hall for Workshop of Meta-synthetic Engineering for SEA.

Inspirations from the scientific discovery of the anammox bacteria: A classic example of how scientific principles can guide discovery and development

Anaerobic ammonium oxidation(anammox) is a relatively new pathway within the N cycle discovered in the late 1990 s. This eminent discovery not only modified the classical theory of biological metabolism and matter cycling, but also profoundly influenced our understanding of the energy sources for life. A new member of chemolithoautotrophic microorganisms capable of carbon fixation was found in the vast deep dark ocean. If the discovery of the chemosynthetic ecosystems in the deep-sea hydrothermal vent environments once challenged the old dogma "all living things depend on the sun for growth," the discovery of anammox bacteria that are widespread in anoxic environments fortifies the victory over this dogma. Anammox bacteria catalyze the oxidization of NH_4^+ by using NO_2^- as the terminal electron acceptor to produce N_2. Similar to the denitrifying microorganisms, anammox bacteria play a biogeochemical role of inorganic N removal from the environment. However, unlike heterotrophic denitrifying bacteria, anammox bacteria are chemolithoautotrophs that can generate transmembrane proton motive force, synthesize ATP molecules and further carry out CO_2 fixation through metabolic energy harvested from the anammox process. Although anammox bacteria and the subsequently found ammonia-oxidizing archaea(AOA), another very important group of N cycling microorganisms are both chemolithoautotrophs, AOA use ammonia rather than ammonium as the electron donor and O_2 as the terminal electron acceptor in their energy metabolism. Therefore, the ecological process of AOA mainly takes place in oxic seawater and sediments, while anammox bacteria are widely distributed in anoxic water and sediments, and even in some typical extreme marine environments such as the deep-sea hydrothermal vents and methane seeps. Studies have shown that the anammox process may be responsible for 30%–70% N_2 production in the ocean. In environmental engineering related to nitrogenous wastewater treatment, anammox provides a new technology with low energy consumption, low cost, and high efficiency that can achieve energy saving and emission reduction. However, the discovery of anammox bacteria is actually a hard-won achievement. Early in the 1960 s, the possibility of the anammox biogeochemical process was predicted to exist according to some marine geochemical data. Then in the 1970 s, the existence of anammox bacteria was further predicted via chemical reaction thermodynamic calculations. However, these microorganisms were not found in subsequent decades. What hindered the discovery of anammox bacteria, an important N cycling microbial group widespread in hypoxic and anoxic environments? What are the factors that finally led to their discovery? What are the inspirations that the analyses of these questions can bring to scientific research? This review article will analyze and elucidate the above questions by presenting the fundamental physiological and ecological characteristics of the marine anammox bacteria and the principles of scientific research.