Carbon dioxide from earthworks: a bottom-up approach.

Concerns over climate change mean engineers need to understand the greenhouse gas emissions associated with infrastructure projects. Standard coefficients are increasingly used to calculate the embodied emissions of construction materials, but these are not generally appropriate to inherently variable earthworks. This paper describes a new tool that takes a bottom-up approach to calculating carbon dioxide emissions from earthworks operations. In the case of bulk earthworks this is predominantly from the fuel used by machinery moving materials already on site. Typical earthworks solutions are explored along with the impact of using manufactured materials such as lime.

Long Distance Wireless Networking for Site - Office Data Communications

Effective data communications between the project site and decision making office can be critical for the success of a construction project. It allows convenient access to centrally stored information and allows centrally located decision makers to remotely monitor the site and collect data in real-time. However, high bandwidth, flexible data communication networks, such as wired local area networks, can often be time-consuming and costly to deploy for such purposes especially when project sites (dams, highways, etc.) are located in rural, undeveloped areas where networking infrastructure is not available. In such construction sites, wireless networking could reliably link the construction site and the decision-making office. This paper presents a case study on long-distance, site – office wireless data communications. The purpose was to investigate the capability of wireless technology in exchanging construction data in a fast and efficient manner and in allowing site personnel to interact and share knowledge and data with the office staff. This study took place at the University of Michigan’s campus where performance, reliability, and cost/benefit tests were performed. The indoor and outdoor tests performed demonstrated the suitability of this technology for office-site data communications and exposed the need for more research to further improve the reliability and data handling of this technology.

微囊藻毒素-RR对反硝化细菌生长及生理特性的影响

用0.01、5.00mg/L微囊藻毒素-RR(MC-RR)处理反硝化细菌,研究了MC-RR对反硝化细菌的生长、培养液中NO3--N和NO2--N含量以及细胞内硝酸还原酶活性的影响。结果表明,高浓度MC-RR能显著抑制反硝化细菌的生长,延缓其细胞增殖,抑制培养液中硝酸盐含量的降低和亚硝酸盐含量的升高以及细胞内硝酸还原酶的活性,因而可能抑制或减缓生态系统中氮循环的进程。这表明,微囊藻毒素在一定程度上可能调节水体细菌群落。