A Review of Multiple Criteria Analysis for Water Resource Planning and Management

Multiple criteria analysis (MCA) is a framework for ranking or scoring the overall performance of decision options against multiple objectives. The approach has widespread and growing application in the field of water resource management. This paper reviews 113 published water management MCA studies from 34 countries. It finds that MCA is being heavily used for water policy evaluation, strategic planning and infrastructure selection. A wide range of MCA methods are being used with the fuzzy set analysis, paired comparison and outranking methods being most common. The paper also examines the motivations for adopting MCA in water management problems and considers future research directions. This study was funded by the eWater CRC ().     

Determination and localisation of in situ substrate uptake by anaerobic wastewater treatment granular biofilms.

Radiotracer incubation experiments and beta microimaging, along with fluorescent in situ hybridisation (FISH), are proposed as a complementary approach to specific methanogenic activity testing and measurement of in vitro substrate utilisation rates to understand better the ecophysiology of anaerobic granular biofilms from wastewater treatment reactors.     

Development of a confined water sensitive urban design (WSUD) system using engineered soils.

Innovative Water Sensitive Urban Design (WSUD) systems are being investigated at three locations to the north and south of Sydney, Australia. These systems contain porous concrete pipes that are designed so that stormwater exfiltrates through the permeable walls of the pipes into the surrounding substrate media material. The porous pipes and media material treat the passing stormwater. The primary aim of the overall project is to develop a model to describe the treatment effectiveness of confined WSUD systems. This paper focuses on the system located at the Weathertex Industrial Site, Heatherbrae. Due to wood processing operations that occur at this site, it is recognised that the surface runoff will carry a heavy organics loading. Granulated Activated Carbon (GAC) is recognised for its ability to reduce the concentration of dissolved organics present in both wastewater and stormwater. GAC was therefore chosen as a filtration medium to be investigated at this site. To maximise the effectiveness of the GAC, extensive laboratory batch studies were undertaken prior to the field system being constructed to determine the optimum GAC/sand ratio. The purpose of the experimental work was to assess the dissolved organic removal potential through sorption of various concentrations of GAC. The aim of this paper is to describe these laboratory experiments and discuss how they related to the field system. Through these experiments it was determined that a sand/GAC ratio of 25:1 was ideal for the media material at the Heatherbrae site.     

Structural and chemical changes of thermally treated bone apatite

The thermal behaviour of the animal by-product meat and bone meal (MBM) has been investigated in order to assess how it is affected structurally and chemically by incineration. Initially composed of intergrown collagen and hydroxyapatite (HAP), combustion of the organic component is complete by 650 °C, with most mass loss (50–55%) occurring by 500 °C. No original proteins were detected in samples heated at 400 °C or above. Combustion of collagen is accompanied by an increase in HAP mean crystallite size at temperatures greater than 400 °C, from 10 nm to a constant value of 120 nm at 800 °C or more. Newly formed crystalline phases appear beyond 400 °C, and include β-tricalcium phosphate, NaCaPO₄, halite (NaCl) and sylvite (KCl). Crystallite thickness as judged by small angle X-ray scattering (SAXS) increases from 2 nm (25–400 °C) to 8–9 nm very rapidly at 550 °C, and then gradually increases to approximately 10 nm. The original texture of HAP within a collagen matrix is progressively lost, producing a porous HAP dominated solid at 700 °C, and a very low porosity sintered HAP product at 900 °C.     

Evaluation of hydroxyapatite coatings on borate passivated 316L SS in Ringer's solution

Surgical grade stainless steel (316L SS) is one of the widely used implant material in orthopedic surgeries. But often the release of metal ions is evidenced from the implants and subsequently a second surgery is required to remove the implant material. One way to control this release of metal ions is to coat the implant material with a biocompatible material like hydroxyapatite. In this paper we have reported a successful coating of hydroxyapatite over borate passivated 316L SS by a dip coating method. The coatings were characterized by electrochemical techniques such as potentiodynamic polarization, electrochemical impedance and cyclic voltammetry (CV). Also X-ray diffraction (XRD) and scanning electron microscopic (SEM) studies were performed to confirm the quality of the coatings. Results of accelerated leach out characteristics by inductively coupled plasma–atomic emission spectroscopy (ICP–AES) and the evaluation of shear strength are also presented to support the corrosion resistant nature of the coatings. The enhanced bio-resistivity of the as-formed HAP coatings on passivated 316L SS is attributed to the protective passive layer formed by borate buffer solution at selected potentials.     

Data express gigabit junction with the next-generation Internet

Important as a very high-performance backbone is to the next generation of the Internet, it is no less important that the points at which people connect to the backbone-the so-called points of presence, or POPs-provide an equivalent level of performance. For almost three years, members of the academic, research, and business community in the North Carolina region known as the Research Triangle-the area lying amid the cities of Raleigh, Durham, and Chapel Hill-have been working to create a high-performance regional network. As partners in the North Carolina Network Initiative (NCNI), they have built a network that can serve as a POP handling the multigigabit traffic to be delivered by the next-generation Internet. Thence comes its name: a GigaPOP. Like a great railway junction, the GigaPOP is a central distribution point where huge amounts of digital freight are moved between various end points and the main line (such as the very high-performance Backbone Network Services, or VBNS). The NCNI is one of a handful of regional networking organizations around the country. The others include the California Research and Education Network 2 (Calren2), the Metropolitan REN (MREN) serving the Chicago area, the Houston Area Computational Science Consortium (HACSC), and the New York State Educational and Research Network (Nysernet). NCNI's work, which predates most initiatives for the Internet's second generation, serves as a model of how various regions can latch onto the coming information superhighway to good effect     

Robot navigation in cluttered 3-D environments using preference-based fuzzy behaviors.

Autonomous navigation systems for mobile robots have been successfully deployed for a wide range of planar ground-based tasks. However, very few counterparts of previous planar navigation systems were developed for 3-D motion, which is needed for both unmanned aerial and underwater vehicles. A novel fuzzy behavioral scheme for navigating an unmanned helicopter in cluttered 3-D spaces is developed. The 3-D navigation problem is decomposed into several identical 2-D navigation subproblems, each of which is solved by using preference-based fuzzy behaviors. Due to the shortcomings of vector summation during the fusion of the 2-D subproblems, instead of directly outputting steering subdirections by their own defuzzification processes, the intermediate preferences of the subproblems are fused to create a 3-D solution region, representing degrees of preference for the robot movement. A new defuzzification algorithm that steers the robot by finding the centroid of a 3-D convex region of maximum volume in the 3-D solution region is developed. A fuzzy speed-control system is also developed to ensure efficient and safe navigation. Substantial simulations have been carried out to demonstrate that the proposed algorithm can smoothly and effectively guide an unmanned helicopter through unknown and cluttered urban and forest environments.     

Single-phase heat transfer in microchannels: The importance of scaling effects

Microscale single-phase heat transfer is widely used in industrial and scientific applications and for this reason, many related papers have been published in the last two decades. Nevertheless, inconsistencies between published results still exist and there is no generally accepted model for the prediction of single-phase heat transfer in microchannels. This paper presents a review of the experimental and numerical results available in the open literature. Heat transfer in microchannels can be suitably described by standard theory and correlations, but scaling effects (entrance effects, conjugate heat transfer, viscous heating, electric double layer (EDL) effects, temperature dependent properties, surface roughness, rarefaction and compressibility effects), often negligible in macro-channels, may now have a significant influence and have to be accounted for. Furthermore, measurement uncertainties may be more important, due to the reduced characteristic dimensions, so have to be accurately checked and, where possible, reduced. Experiments with single channels are more accurate and in good agreement with predictions from published correlations, in contrast to multi-(parallel) channel experiments. The latter are subject to maldistribution, 3D conjugate heat transfer effects and larger measurement uncertainties. Sub-continuum mathematical models for fluid dynamics are briefly reviewed and explained. These models are expected to gain a growing interest in the near future due to the rapid descent of microchannel dimensions down to the nano-scale. The paper concludes with a concise set of recommendations for purposes of performance and design. For single channels, available correlations for macro-channels can also give reliable predictions at the micro-scale, but only if all the scaling effects can be considered negligible. Otherwise, when scaling effects cannot be neglected or for the case of heat exchangers with parallel channels, suitable numerical simulations may be the sole alternative to carefully designed experiments to evaluate the heat transfer rates.     

Arbitrarily Shaped Fiber Assemblies from Spun Carbon Nanotube Gel Fibers

Experimental methods, apparatus, and practically useful theoretical analysis are provided for the coagulation‐based spinning of effectively unlimited lengths of carbon nanotube fibers having exceptional toughness and reasonably high strength. This spinning process fundamentally depends on the mechanical properties of intermediate gel state fibers, which we find are surprising elastic up to about 20 % strain and sufficiently strong for diverse processing methods. More specifically, we show that assemblies of these gel fibers can be used as intermediates for making nanotube sheets, large diameter fibers, and conformal coatings. When suitably processed, these composites (comprising many parallel solution‐spun nanotube fibers) have useful strength and extraordinary toughness.     

Optimal Semicomputable Approximations to Reachable and Invariant Sets

In this paper we consider the computation of reachable, viable and invariant sets for discrete-time systems. We use the framework of type-two effectivity, in which computations are performed by Turing machines with infinite input and output tapes, with the representations of computable topology. We see that the reachable set is lower-semicomputable, and the viability and invariance kernels are upper-semicomputable. We then define an upper-semicomputable over-approximation to the reachable set, and lower-semicomputable under-approximations to the viability and invariance kernels, and show that these approximations are optimal.