腐蚀产物性质对金属大气腐蚀过程影响的研究

首先简要阐述了金属大气腐蚀的机理及过程,介绍了大气腐蚀过程中腐蚀产物的种类。然后分别从腐蚀产物的物理性质、化学性质(电化学)等方面对金属大气腐蚀过程影响的研究进行了探讨,并着重总结了腐蚀产物光电性质对金属腐蚀的影响。最后对该研究方向进行了展望。     

重复再生混凝土性能和环境影响研究

基于生命周期评价方法,考虑混凝土重复再生利用的环境影响分配,对重复再生混凝土的性能和环境影响进行研究,并基于功效系数法优化出混凝土最佳重复再生次数.研究结果表明,再生混凝土的坍落度,强度和电通量随着重复再生循环次数的增加而下降,经3次重复再生后,混凝土28d立方体抗压强度为33.3MPa,满足设计要求,而坍落度和电通量与普通混凝土相比,分别减小和增大了38.9%和85.7%;混凝土材料的生态效率随着混凝土重复再生次数的增加而提高,混凝土材料的GWP、CED和CMR的值均随着混凝土重复再生次数的增加而降低,降低幅度从高到低依次为：CMR > GWP > CED;综合考虑混凝土的坍落度,混凝土抗压强度、电通量、GWP、CED和CMR等6个指标,4种混凝土配合比情景中,混凝土总功效系数从高到低依次为：一次再生混凝土 > 二次再生混凝土 > 三次再生混凝土 > 普通混凝土.     

ZnO纳米材料的制备及其光催化性能研究

采用有机液相合成法合成ZnO纳米材料,分析了制备ZnO纳米材料的机理,研究了配比、煅烧、煅烧温度等因素对制备的ZnO纳米材料光催化降解染料废水的影响。通过TEM,XRD,XPS等手段对其成分、形貌及晶体结构进行表征。实验结果显示,制备的ZnO纳米材料煅烧前粒径为5.9 nm,煅烧后粒径为37.1 nm,煅烧可以提高其光催化性能,最佳原料配比为5∶1,最佳煅烧温度为500℃。     

围栏封育对巴音布鲁克草原土壤理化性质的影响

为明确长期围栏封育对新疆亚高山草原土壤理化性质的影响,本研究以巴音布鲁克草原围封26年的高寒草甸、高寒草甸草原和高寒草原为研究对象,对三种类型草地围栏内外土壤理化性质进行对比分析,结果表明:(1)高寒草甸和高寒草原围栏内表层土壤饱和含水量、田间持水量和土壤含水量均高于围栏外样地,而土壤容重均低于围栏外,其中高寒草甸围栏内外的田间持水量、土壤含水量和土壤容重的差异达到显著水平;(2)高寒草甸围栏内表层土壤有机质含量显著高于围栏外,全氮则显著低于围栏外;三种类型草地围栏内表层土壤全磷含量均低于围栏外;(3)相关性分析表明,土壤含水量高的草地,其饱和含水量和田间持水量也较高,土壤容重较小;土壤容重高的草地其有机质含量较低;速效钾含量高的草地,其全磷含量也较高。围栏封育有利于草地土壤理化性质的恢复,但长时间围封会降低土壤磷素含量,需要通过施肥等管理措施补充以促进草地生态系统保持良性状态,本研究对草地土壤质量调控和退化草地恢复研究具有参考意义。     

光学迷宫对飞机货舱感烟探测器响应性能的影响

针对飞机货舱火灾的探测延迟性问题,探讨了光学迷宫对点型光电感烟探测器响应性能的影响,实验研究了点型光电感烟探测器在有、无迷宫两种情况下烟雾探测的响应过程,对比分析了不同烟量时迷宫的作用,并提出探测器迷宫结构的改进设计思路。实验结果表明,在探测器响应过程中,有光学迷宫的探测器烟雾浓度波动幅度较小,迷宫对烟气有滞留作用,提高了探测器的稳定性;但迷宫会使探测腔室的烟雾浓度明显滞后且低于腔外,增大了探测器的迟滞时间,烟雾浓度较低时这种迟滞影响更为明显,严重影响货舱火警探测器的灵敏度。     

污泥厌氧消化系统消化原料流变特性研究

考察了4种污泥厌氧消化原料的流变特性,研究了原料浓度、温度以及添加餐厨垃圾等因素对污泥流变特性的影响,以期为厌氧消化工艺的设计及设备选用提供基础参数.试验结果表明,脱水污泥、脱水污泥与餐厨垃圾混合物、剩余污泥、剩余污泥与餐厨垃圾混合物4种原料均为假塑性流体,且符合幂律方程.随消化原料固体浓度由1%增至10%,原料黏度升高.剩余污泥和剩余污泥与餐厨垃圾混合物在TS=3%时流变指数最大,而脱水污泥和脱水污泥与餐厨垃圾混合物在TS=5%时流变指数最大.添加餐厨垃圾可以改善污泥的流变特性,使得混合液的流变指数较纯污泥有不同程度的升高,使其更接近牛顿流体.随着温度由15℃升高到55℃,4种原料的黏度呈线性趋势降低,流变指数则逐渐升高,其中脱水污泥的黏度对温度变化最为敏感.     

Shellfish aquaculture and First Nations' sovereignty: The quest for sustainable development in contested sea space

Aquaculture tenures or leases have become an increasingly important management tool for regulating access rights to coastal and offshore marine habitat. Tenure, as a form of private property rights to marine space, is generally considered a prerequisite for aquaculture development, as are the associated exclusive access rights which provide necessary incentives for producers to invest in infrastructure. The shellfish industry in British Columbia (BC), Canada, is presented as a case study of a transition from a primarily common property wild fishery to a rights‐based system for aquaculture. In BC, seafood production has grown substantially during the past two decades as a result of aquaculture production. However, despite the inherent economic advantages of the tenuring system for increasing seafood production, rights to aquaculture sites in BC remain highly controversial, particularly in response to environmental concerns and infringements on Aboriginal territorial claims. Shellfish farming has, to‐date, been far less controversial than salmon farming; however, shellfish aquaculture has not been uniformly adopted across the province, and analyses of industry capacity or economic opportunities for coastal communities have failed to adequately explain development patterns. This paper, which identifies perceptions of the risks and benefits of the shellfish aquaculture tenuring system, presents the results of 56 interviews conducted with individuals involved in shellfish production in BC. Results indicate that heightened perceptions of risk about shellfish aquaculture tenuring are related to unresolved Aboriginal territorial claims, economic dependence on wild shellfish resources, as well as place‐based values favouring access to wild resources. Underlying values and cultural understandings also strongly shape public perceptions of the risks of aquaculture, and as such, influence local decisions to either accept or resist industry growth. In this case, interviewees' risk perceptions were found to be more important indicators of the potential for industry expansion than studies of capacity or economic cost‐benefit analyses.     

A multiscale hierarchical Markov transition matrix model for generating and analyzing thematic raster maps

A model is described for generating hierarchically scaled spatial pattern as represented in a thematic raster map. The model involves a series of Markov transition matrices, one for each level in the scaling hierarchy. In full generality, the model allows the transition matrices to be different at each level, potentially making available a large number of parameters for landscape characterization. The model is self-similar when the transition matrices are all equal. A method is presented for fitting the model to data that take the form of a single-resolution thematic raster map. Explicit analytic solutions are obtained for the fitted parameters. The fitting method is based on a relationship between the hierarchical transitions in the model and spatial transitions at varying distance scales in the data map, a categorical analogy of the geostatistical variogram.     

Preparation of controlled nano-MgO and investigation of its bactericidal properties

Nano-MgO is a good bactericide but with strong alkalinity in water due to its rapid hydrolysis. To control its hydrolysis rate and keep its bactericidal properties, we synthesized nano-MgO microspheres using chitosan-alginate system in this study. The synthesized nano-MgO release-controlled microspheres (nMgO-RCM) were with 0.98-1.20 mm of particle sizes. Also, their embedding ratio and loading percentage was 63.52% and 12.27%, respectively. Based on the characterization results, nano-MgO was only observed on surface of the nMgO-RCM. Its release rate from the nMgO-RCM could be controlled by the chitosan-alginate system, and the observed rate constant (k_obs) increased from 0.0289 h⁻¹ to 0.0358 h⁻¹ with the increment of the dosage from 10 mg L⁻¹ to 80 mg L⁻¹. Furthermore, the nMgO-RCM could maintain pH value lower than 8.5 and colony counts less than 20 CFU mL⁻¹ for at least 120 h.     

A Transactions Cost Approach to the Theoretical Foundations of Water Markets1

Abstract: Water marketing is often cited as a means of alleviating the stresses attached to allocation of water use. Frequently, marketing is suggested in a context that implies substitution of competitive markets for the allocation based on the prior appropriation doctrine. This study examines water marketing from the perspective of a transactions cost approach to the private and broad social agreements (contracts) that support water allocation. It examines the major behavioral challenges faced by any contract, and the alternative approaches to those challenges, with respect to water allocation. It also examines the impact of market design on the existence of externalities, costs imposed by transactions on society and individuals not party to the transaction. It finds that the most robust water market designs will be found in systems with sufficient property rights protection to support investment, sufficient hydrologic information to provide accurate analysis of third party effects, conjunctive management of surface and groundwater, and a governance structure capable of administering the rules while not determining outcomes.