Remarkable Antibacterial Activity of Reduced Graphene Oxide Functionalized by Copper Ions

Despite long-term efforts for exploring antibacterial agents or drugs, potentiating antibacterial activity and meanwhile minimizing toxicity to the environment remains a challenge. Here, it is experimentally shown that the functionality of reduced graphene oxide (rGO) through copper ions displays selective antibacterial activity that is significantly stronger than that of rGO itself and no toxicity to mammalian cells. Remarkably, this antibacterial activity is two-orders-of-magnitude greater than the activity of its surrounding copper ions. It is demonstrated that rGO is functionalized through the cation–π interaction to massively adsorb copper ions to form a rGO–copper composite and result in an extremely low concentration level of surrounding copper ions (less than ≈0.5 µm ). These copper ions on rGO are positively charged and strongly interact with negatively charged bacterial cells to selectively achieve antibacterial activity, while rGO exhibits the functionality to not only actuate rapid delivery of copper ions and massive assembly onto bacterial cells but also result in the valence shift in the copper ions from Cu²⁺ into Cu⁺, which greatly enhances the antibacterial activity. Notably, this rGO functionality through cation–π interaction with copper ions can similarly achieve algaecidal activity but does not exert cytotoxicity against neutrally charged mammalian cells.     

Quality, Environmental, and Health and Safety Management Systems for Construction Engineering

The philosophy behind quality, environmental, and safety (QES) management systems is a concept that has been accepted by various contractors. Furthermore, a process has been developed insuring that the output produced conforms to customer satisfaction without violating any environmental, health, and safety rules and regulations. An effective QES program not only assures a quality product but also reduces costs, and enhances productivity. It is a top down process, i.e., top management together with line management and other employees develop the program and motivate all personnel to accept the process. Important functions to take under consideration are (1) explain and clarify the quality, environmental, and safety performance expected; (2) involve employees in decision-making and problem solving; (3) describe the consequences of poor quality and unsafe/unhealthy work conditions; (4) establish QES goals and provide feedback on performance; (5) provide a self-monitoring system; and (6) recognize and reinforce good performance and develop a reward system. This paper presents a discussion of the development of a portion of a QES management system which has been employed by a medium to large size construction company. In particular, Items 1–4, listed above, are described in detail.     

论建材集贸市场的消防安全现状及预防对策

结合建材集贸混合市场火灾隐患整治试点工作,就集贸市场的消防安全现状、火灾危险性和消防安全管理情况总结了几点认识,以全面推进该类市场火灾隐患综合整治,确保消防安全。     

页岩气平台测试流程优化研究与应用

针对页岩气大排量、大砂量压裂后,排采测试流程设备繁多、作业效率低、天然气计量误差大、流程易堵塞等问题,对现有测试流程的设备、计算方法、数据采集系统等进行改进,设计了新型转向功能模块流程和固相物捕捉系统,对比分析了四种天然气产量计算方法,并引入了数据采集系统.通过现场试验表明,该研究成果的应用减少了设备的使用,提高了天然...     

Reliability assessment for systems suffering common cause failure based on Bayesian networks and proportional hazards model

The Bayesian network (BN) is an efficient tool for probabilistic modeling and causal inference, and it has gained considerable attentions in the field of reliability assessment. The common cause failure (CCF) is simultaneous failure of multiple elements in a system under a common cause, and it is a common phenomenon in engineering systems with dependent elements. Several models and methods have been proposed for modeling and assessment of complex systems with CCF. In this paper, a new reliability assessment method is proposed for the systems suffering from CCF in a dynamic environment. The CCF among components is characterized by a BN, which allows for bidirectional reasoning. A proportional hazards model is applied to capture the dynamic working environment of components and then the reliability function of the system is obtained. The proposed method is validated through an illustrative example, and some comparative studies are also presented.     

煤矿水害治理多分支水平井精准定导向技术研究

多分支水平井注浆技术因其施工成本低、环境污染小、隔水效果好等特点,被广泛应用于煤矿水害治理中。但由于煤层底板普遍存在断层发育、目的层薄、破碎带聚集等复杂情况,施工时常出现泥浆漏失、顺层钻进困难、穿越断层易卡钻等难题,严重影响了注浆治理效果。针对这些问题,本文以安徽某煤矿为例,在对其地质特征进行分析的基础上,从定向轨迹设计、定导向设备选型以及井眼轨迹控制等方面展开研究,将定向钻进和地质导向技术结合,优化复杂地质条件下多分支水平井定导向技术,并成功应用于多分支水平井超前注浆改造工程中。现场应用表明,该技术提高了井眼轨迹控制的精确性,保证了目的层钻遇率,应用效果良好。     

铜矿选矿废水处理研究现状与展望

铜矿选矿过程产生的废水含有的污染物多,导致周边环境严重污染。随着我国水资源的短缺及环保要求的日益严格,对废水的处理是亟需解决的问题。本文以铜矿选矿废水为研究对象,分析了其来源、基本特征以及对环境的危害性,针对铜矿选矿废水中的固体悬浮物、重金属离子和有机选矿药剂,分别阐述了自然沉降、吸附、絮凝、化学沉淀以及高级氧化等处理方法,并对各种方法的机理及优缺点进行总结分析。探讨了铜矿选矿废水在处理中存在的问题,对废水的治理研究进行展望,应开发高效且生态友好的废水处理新工艺,降低废水对环境的污染,实现废水的高效治理。     

安溪县气象-地质灾害监测预警报系统建设方案综析

随着全球气候的进一步恶化、人类工程活动的日益频繁 ,地质灾害对社会和经济发展的影响更加明显 ,防治工作也给我们提出了更高的要求。目前我们已初步摸索出一套基层防治灾害的管理经验 ,这也是防治工作的又一个重大举措 ,并收到了良好的效益     

TSP超前地质预报在岩溶隧道中的应用

针对湖北大广高速公路建设中紫荆山高岩溶隧道工程,利用TSP超前地质预报技术,并结合隧道工程地质情况,通过准确预报工作,阐述了TSP超前地质预报的基本原理和方法,探讨了该技术在紫荆山隧道施工过程中的应用效果,并将预报结果与实际工程进行对比,验证了该技术的可靠性。     

露天矿山开采职业危害因素辨识与防范措施

全面分析露天矿山职业安全危害和职业病危害因素,并针对性地提出防范措施,以减少职业危害,确保生产者职业安全和职业健康。