Volume 2 Issue 1
Authors: Steven B. Mitchell; Roger K. A. Morris
Abstract: The role of anthropogenic modification of the Humber estuary (England, UK) is examined in the context of its exceptionally high suspended sediment concentrations (SSCs). Loss of accommodation space through land claim for agriculture over the past 1,000 years has led to the evolution of channel that may be described as a tidal canal. We explore some relevant analogues in order to determine whether any correlation exists among the degree of narrowing, the extent of tidal propagation, and the persistence of elevated SSCs. Several examples are shown of estuaries whose tidal range and SSC have been manipulated by anthropogenic changes to their geometry. It is postulated that this modern form has resulted in increased tidal propagation and that elevated sediment loads within the Humber Estuary have been influenced by a loss of accommodation space. We propose that should this association be substantiated then accommodation space should be regarded as a significant ‘ecosystem function’ in regulating suspended sediment concentrations and water quality. Our analysis highlights a suite of ecosystem services that include the regulation of tidal range as well as of SSC. It provides the basis for a broader approach to coastal management in which the role of accommodation space is given a higher profile from an engineering perspective. A wider suite of biochemical benefits may also arise in the aftermath of substantial realignments, emphasising the broader relationship between managed realignment, sediment availability and ecological functioning.
Keywords: Accommodation Space; Suspended Sediment Concentrations; Tidal Propagation; Managed Realignment; Ecosystem Services
Authors: M. Saeedi; H. Kheirkhah Gildeh; E. E. Eshtehardian; R. Taheriattar; R. Taheriattar
Abstract: Shahid Rajaee Power Plant, located about 100 km west of Tehran, is one of the Iran’s biggest thermal power plants. During the operation of the plant, different kinds of wastes are produced. Dewatered sludge waste from air heater washing wastewater treatment of the plant was subjected to investigation of the cement-based Solidification/Stabilization (S/S) experiments to reduce the mobility of heavy metals. By reviewing the production procedure of this waste, it can be conjectured that this waste probably contains a variable range of heavy metals such as V, Ni, Zn and Cr. In the present study, the S/S method was used to convert this waste into nonhazardous by using both Portland Cement Type I (CEMI) and standard sand (Ottawa Sand) as additive materials. The compressive strength of the samples with different amounts of waste was examined in order to study the changes in the bearing characteristic of the samples, in comparison with the control sample. Microscopic characteristics of both raw and solidified waste samples were observed using a Research Polarize Microscope (RPM). The compressive strength test results reported only about 30% decrease in the results of the samples with waste, comparing to control concrete sample without waste.
Keywords: Thermal Power Plant; Hazardous Sludge Waste; Solidification/Stabilization; Environmental Engineering; Concrete
Authors: Kalle Kahkonen; Marco A. Bragadin
Abstract: The measurement of the performance of a construction project is a fundamental task of Construction Management. This is usually based on professional observations or use of metrics such as Key Performance Indicators (KPIs), that are intended to represent the health of the construction project and can be used to predict the future project performance. This paper presents a research effort on the way forward to implement quality related metrics for construction project control. The Quality Breakdown Structure is adopted as basic tool to consider the various elements of construction quality like product quality and process quality, to put them into relationship and to evaluate their relative weight in the construction project and its sub-processes. The proposed quality related performance indicators can be loaded to the construction project scheduling model, with the goal of showing to Project Manager and to Stakeholders the achieved versus planned quality in the project status. This could improve construction project control process, with the aim of the timely implementation of corrective actions to achieve project success.
Keywords: Construction; Project Control; Quality; Project Managemen; Construction Performance