喷丸强化对超高强度钢耐腐蚀性能的影响

目的提高舰载机结构疲劳关键部位的主体材料超高强度钢的耐蚀性能。方法基于实测的环境数据编制加速腐蚀试验环境谱,针对喷丸和未喷丸超高强度钢试验件在实验室条件下开展加速腐蚀试验,从宏观/微观形貌、质量损失、腐蚀速率和表面粗糙度等方面表征腐蚀行为,分析讨论喷丸强化对超高强度钢耐腐蚀性能的影响。结果超高强度钢腐蚀初期为局部点蚀,然后转变为全面均匀腐蚀。喷丸强化延缓了腐蚀形态转变的时机,喷丸试验件腐蚀速率约为未喷丸试验件的75%,加速腐蚀当量为3 a,未喷丸和喷丸试验件表面平均粗糙度分别为5.67mm和4.16mm,前者为后者的1.36倍。结论通过质量损失率、腐蚀速率和表面粗糙度的对比分析知,喷丸强化明显提高了超高强度钢的耐腐蚀性能。     

应用物种敏感性分布评估重金属对海洋生物的生态风险

应用生态风险评价中的物种敏感性分布(species sensitivity distributions,SSD)方法构建了8种常见重金属元素(As、Cd、Cr、Cu、Hg、Mn、Pb、Zn)对海洋生物的SSD曲线。在此基础上计算了8种重金属对海洋生物的5%危害浓度(HC5)及其不同暴露浓度对海洋生物的潜在影响比例(PAF),比较了海洋脊椎动物和无脊椎动物对8种重金属的敏感性以及不同重金属的急性生态风险。结果表明,重金属对甲壳类的生态风险均比鱼类大。8种重金属元素对所研究的海洋生物全部物种的HC5值的排序为Pb>Mn>Zn>Cr>Cu>Hg>Cd>As。暴露浓度小于10μg·L-1时,Cr和Hg的生态风险差异不大。在10μg·L-1的暴露浓度下,As、Cd、Cu和Hg均使全部物种中超过10%的生物受到影响。随着浓度升高,不同重金属的生态风险有不同幅度的增大,当浓度达到1000μg·L-1时,分别有82.49%、87.31%和85.90%的物种受到As、Cu和Hg的损害。不同生物的敏感性顺序会随重金属的浓度范围发生变化。     

牡蛎和贻贝中二噁英及多氯联苯同类物的分布

利用同位素稀释、高分辨气相色谱-高分辨质谱联用仪，首次测定了大连湾牡蛎和贻贝等海洋生物体内痕量的二噁英和多氯联苯，并比较了二噁英及多氯联苯的同类物在牡蛎和贻贝中的含量分布。结果表明，所采集的牡蛎和贻贝样品中均含有二噁英和多氯联苯，且多氯联苯的含量明显高于二噁英，反映出环境中多氯联苯背景值大于二噁英的背景值。其中，牡蛎和贻贝中二噁英总质量分数平均值分别为47．8pg／g和216pg／g(以干物质计)，毒性当量平均值分别为O．89pg／g和0．87pg／g；12种有毒性的共平面多氯联苯的总质量分数平均值分别为585．5pg／g和818．6pg／g，总毒性当量平均值分别为0．47pg／g和1．18pg／g。牡蛎和贻贝样品中的二噁英及多氯联苯的同类物含量分布基本类似，表明二者摄取的二噁英及多氯联苯可能有相似的来源。可以把牡蛎和贻贝作为生物标志物，以监测海洋环境中二噁英和多氯联苯的污染状况。     

Ca2+与CO32-协同作用对MAP结晶法去除污泥厌氧消化液中磷的影响

以模拟厌氧消化液为处理对象,进行了磷酸铵镁(MAP)结晶实验,考察了p H值、CO2-3、Ca2+以及CO2-3和Ca2+共存对磷酸铵镁结晶反应的影响;利用扫描电子显微镜(SEM-EDX)、X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)对产物进行了表征.结果表明,随着p H值升高,磷的去除率显著提高,并在p H值为9.5时得到具有良好沉降性能的针状MAP晶体;CO2-3的存在会使磷去除率降低,在实验设定CO2-3浓度最大的条件下,磷去除率降低约17%,同时CO2-3会削弱Ca2+对MAP结晶反应的贡献,但并不改变MAP晶体形态和纯度;Ca2+存在则可以提高P去除率,但对MAP结晶反应抑制作用显著,当体系中n(Ca)/n(Mg)0.65,产物主要以无定形磷酸钙盐为主;在Ca2+与CO2-3共存的体系中,Ca2+可有效地消除CO2-3对除磷效果的影响,随着两者浓度的增加,产物Ca CO3含量增多,磷酸盐则主要以MAP形式沉淀.     

温度对海洋厌氧氨氧化菌脱氮效能的影响

采用ASBR反应器,研究了不同温度对海洋厌氧氨氧化菌处理含海水污水脱氮效能的影响,并利用修正的Logistic模型模拟不同温度下海洋厌氧氨氧化菌的动力学特性.结果表明,在25~35℃之间,温度对反应器的脱氮效能影响不大,总氮去除率(TNRE)基本保持在(82±2)%,总氮容积负荷去除速率(TNRR)稳定在(0.62±0.01)kg·(m~3·d)~(-1);在20℃时,TNRE从起始的59%经过13d上升到79%,说明在此温度下,海洋厌氧氨氧化菌仍然具有较强的脱氮能力,反应器在较低温处理含海水污水具有较好的发挥潜能;然而当温度降到15℃和10℃时,反应器的脱氮效能受到明显的抑制,TNRE分别下降至(40±8)%和(11±4)%,TNRR也下降至(0.30±0.04)kg·(m~3·d)~(-1)和(0.08±0.03)kg·(m~3·d)~(-1).根据Arrhenius方程得到,在25~35℃时,海洋厌氧氨氧化反应的活化能为26 k J·mol~(-1),在10~25℃时,海洋厌氧氨氧化反应的活化能为76 k J·mol~(-1).此外,通过Logistic模型对海洋厌氧氨氧化脱氮进行动力学分析,得到不同温度下NRE和出水总氮浓度(ceff)的预测公式,相关系数R2在0.966 8~0.995 7之间.     

微生物诱导碳酸盐沉淀及其在固定重金属领域的应用进展

生物矿化已受到化学、物理、生物、材料、医学、生命及环境等多学科的广泛关注,其中,以尿素为底物的MICP（微生物诱导碳酸盐沉淀）技术是生物矿化领域的研究热点之一.在分析MICP过程中的酶解机理和生物大分子在微生物矿化过程中的作用基础上,通过对重金属离子的矿化产物和碳酸盐矿化菌的成矿因素分析,揭示MICP矿化产物的特征及形成条件.碳酸盐矿化菌主要产生脲酶分解尿素,增加土壤CO₃2-饱和度,其代谢产生的胞外聚合物具有多种功能团组合和键能连接,起着调控生物矿化的作用.MICP技术可用于固定土壤和水体中的Cu、Pb、Zn、Cd、Cr、As等重金属,重金属主要以共沉淀的形式被固定,阴阳离子型重金属以类质同象置换方式分别占据方解石中的CO₃2-位和Ca2+位,从而促使污染土壤中的可交换态重金属向碳酸盐结合态转移.但是,MICP技术主要针对减少重金属的生物可利用性,不能满足以全量来计算的现行土壤环境质量标准,且MICP技术在长期有效性、生物安全性和土壤理化性质等方面存在诸多隐患.因此,由试验条件转向实际应用具有一定挑战.建议寻找更稳定的方法以阻止碳酸盐矿物中的重金属溶出,且有必要将开发高效的土著微生物复合菌剂作为未来MICP研究的方向之一.      

海洋环境中电偶腐蚀研究进展

从影响因素和微区电化学技术2个方面详细论述了海洋环境中电偶腐蚀的研究现状,分析了电位差、面积比和温度等主要因素对电偶腐蚀规律的影响.简要介绍了开尔文探针、阵列电极、扫描微电极等微区电化学测量技术在电偶腐蚀研究中的应用,并对今后的电偶腐蚀研究方向进行了展望.     

Dynamic catch trends in the history of recreational spearfishing in Australia

The sustained decline in marine fisheries worldwide underscores the need to understand and monitor fisheries trends and fisher behavior. Recreational fisheries are unique in that they are not subject to the typical drivers that influence commercial and artisanal fisheries (e.g., markets or food security). Nevertheless, although exposed to a different set of drivers (i.e., interest or relaxation), recreational fisheries can contribute to fishery declines. Recreational fisheries are also difficult to assess due to an absence of past monitoring and traditional fisheries data. Therefore, we utilized a nontraditional data source (a chronology of spearfishing publications) to document historical trends in recreational spearfishing in Australia between 1952 and 2009. We extracted data on reported fish captures, advertising, and spearfisher commentary and used regression models and ordination analyses to assess historical change. The proportion of coastal fish captures reported declined approximately 80%, whereas the proportion of coral reef and pelagic fish reports increased 1750% and 560%, respectively. Catch composition shifted markedly from coastal temperate or subtropical fishes during the 1950s to 1970s to coral reef and pelagic species in the 1990s to 2000s. Advertising data and commentary by spearfishers indicated that pelagic fish species became desired targets. The mean weight of trophy coral reef fishes also declined significantly over the study period (from approximately 30–8 kg). Recreational fishing presents a highly dynamic social–ecological interface and a challenge for management. Our results emphasize the need for regulatory agencies to work closely with recreational fishing bodies to observe fisher behavior, detect shifts in target species or fishing intensity, and adapt regulatory measures. Tendencias Dinámicas de Captura en la Historia de la Pesca Recreativa con Arpón en Australia     

Pollution,habitat loss,fishing, and climate change as critical threats to penguins

Cumulative human impacts across the world's oceans are considerable. We therefore examined a single model taxonomic group, the penguins (Spheniscidae), to explore how marine species and communities might be at risk of decline or extinction in the southern hemisphere. We sought to determine the most important threats to penguins and to suggest means to mitigate these threats. Our review has relevance to other taxonomic groups in the southern hemisphere and in northern latitudes, where human impacts are greater. Our review was based on an expert assessment and literature review of all 18 penguin species; 49 scientists contributed to the process. For each penguin species, we considered their range and distribution, population trends, and main anthropogenic threats over the past approximately 250 years. These threats were harvesting adults for oil, skin, and feathers and as bait for crab and rock lobster fisheries; harvesting of eggs; terrestrial habitat degradation; marine pollution; fisheries bycatch and resource competition; environmental variability and climate change; and toxic algal poisoning and disease. Habitat loss, pollution, and fishing, all factors humans can readily mitigate, remain the primary threats for penguin species. Their future resilience to further climate change impacts will almost certainly depend on addressing current threats to existing habitat degradation on land and at sea. We suggest protection of breeding habitat, linked to the designation of appropriately scaled marine reserves, including in the High Seas, will be critical for the future conservation of penguins. However, large‐scale conservation zones are not always practical or politically feasible and other ecosystem‐based management methods that include spatial zoning, bycatch mitigation, and robust harvest control must be developed to maintain marine biodiversity and ensure that ecosystem functioning is maintained across a variety of scales. Contaminación, Pérdida de Hábitat, Pesca y Cambio Climático como Amenazas Críticas para los Pingüinos     

Toward an improved ecosystem based management approach: incorporating catchment characteristics into better management and planning of the Great Barrier Reef marine ecosystem

Discharge from the Great Barrier Reef Catchment (GBRC) is considered the second most serious threat to the Great Barrier Reef, Australia. Utilising principal component analysis (PCA) and cluster analysis (CA), this research aimed to assess the variability and co-variation of 28 water basins (WBs) within the GBRC, in order to improve the institutional arrangements and regulation of water quality and increase collaboration horizontally between management organisations, and vertically between government tiers. Water basin variability was measured by nine variables: size (ha), population, agricultural land use (ha), number of major water storages, major rivers and major towns, total nitrogen exported (T/yr), total phosphorus exported (T/yr) and herbicide use (ha). The Fitzroy WB, with PC scores of 7.0081, 2.2897 and ?1.6504, was identified as the most dissimilar and therefore needing to be managed differently. Many WBs within the same regions were very dissimilar to each other, indicating that current management practices, based largely on geographic location, are unlikely to be the most efficient and effective. Instead, managing groups of WBs with similar geo-political properties (determined by the CA) could be more effective and efficient. Coordination and collaboration are key to successful ecosystem based management, therefore managing similar WBs together through inter-NRM (natural resource management) agreements, irrespective of their geographical location, facilitates management bodies building strong, cooperative working relationships.