A Genetic Fuzzy Analytical Hierarchy Process Based Projection Pursuit Method for Selecting Schemes of Water Transportation Projects

The optimal selection of schemes of water transportation projects is a process of choosing a relatively optimal scheme from a number of schemes of water transportation programming and management projects, which is of importance in both theory and practice in water resource systems engineering. In order to achieve consistency and eliminate the dimensions of fuzzy qualitative and fuzzy quantitative evaluation indexes, to determine the weights of the indexes objectively, and to increase the differences among the comprehensive evaluation index values of water transportation project schemes, a projection pursuit method, named FPRM-PP for short, was developed in this work for selecting the optimal water transportation project scheme based on the fuzzy preference relation matrix. The research results show that FPRM-PP is intuitive and practical, the correction range of the fuzzy rained is both stable and accurate; preference relation matrix A it produces is relatively small, and the result obtherefore FPRM-PP can be widely used in the optimal selection of different multi-factor decision-making schemes.

Effective Management of Performance Based Maintenance Contracts(PBMC)by Adopting Asset Management Concepts

PBMC(performance-based maintenance contracts)provides incentives and/or disincentives to the contractor to achieve desired outcomes or results.In other words,the concept of PBMC is to pay a contractor based on the actual results(performance or LOS(level of service)),not on the performed work.PBMC does not detail to the contractor how,when,or where to do the work.Instead,it specifies performance standards or targets for measurable outcomes and sometimes outputs.There are several benefits from implementing PBMC.Higher LOS,i.e.,better quality,potential reduction in agency costs and downsized maintenance workforce are among these benefits.Also,there are several challenges facing the implementation of PBMC.One of the most complex challenges that relates to both the agency and contractor,and in some cases to the public,is how to manage LOS in an objective manner and to demonstrate that policy goals and objectives regarding quality of life expectancy are achieved without any increase in the LCC(life cycle cost)of the assets.This challenge,along with many other challenges,can be addressed through the adoption of an AM(asset management)approach.AM approach facilitates the long-term planning based on the current and future conditions and desired LOS.In addition,AM provides the necessary tools to objectively monitor LOS,and hence the contractor performance,which will contribute to the success of the implementation of PBMC.

Reactive Transport Modeling of Long-Term CO2 Sequestration Mechanisms at the Shenhua CCS Demonstration Project,China

Carbon dioxide injection into deep saline aquifers results in a variety of strongly coupled physical and chemical processes. In this study, reactive transport simulations using a 2-D radial model were performed to investigate the fate of the injected CO2, the effect of CO2-water-rock interactions on mineral alteration, and the long-term CO2 sequestration mechanisms of the Liujiagou Formation sandstone at the Shenhua CCS（carbon capture and storage） pilot site of China. Carbon dioxide was injected at a constant rate of 0.1 Mt/year for 30 years, and the fluid flow and geochemical transport simulation was run for a period of 10 000 years by the TOUGHREACT code according to the underground conditions of the Liujiagou Formation. The results show that different trapping phases of CO2 vary with time. Sensitivity analyses indicate that plagioclase composition and chlorite presence are the most significant determinants of stable carbonate minerals and CO2 mineral trapping capacity. For arkosic arenite in the Liujiagou Formation, CO2 can be immobilized by precipitation of ankerite, magnesite, siderite, dawsonite, and calcite for different mineral compositions, with Ca（2＋）, Mg（2＋）, Fe（2＋） and Na＋ provided by dissolution of calcite, albite（or oligoclase） and chlorite. This study can provide useful insights into the geochemistry of CO2 storage in other arkosic arenite（feldspar rich sandstone） formations at other pilots or target sites.