Challenges and opportunities for participatory planning approaches within Dubai’s urban context

Dubai has been in the midst of a profound physical transformation, radically affecting the lives of residents and newcomers. Within US and European models of planning, the rapid change Dubai is experiencing calls for public involvement in charting the city’s future. However, Dubai’s neo-patrimonial governance concentrates planning decisions into the hands of trusted elites, lacking public participation. How might a participatory approach to planning be successfully implemented in Dubai? First, this article applies Delphi to obtain experts’ knowledge about the feasibility of implementing a participatory planning approach in Dubai. Second, the first author interviewed government officials to identify constraints for implementing strategies intended to widen public participation. Last, recommendations for the implementation of a more transparent approach to planning are provided. The article concludes with questions that explore the challenges associated with participation in planning decision-making specifically for neo-patrimonial systems.     

Amyloid-β and Astrocytes Interplay in Amyloid-β Related Disorders

Amyloid-β (Aβ) pathology is known to promote chronic inflammatory responses in the brain. It was thought previously that Aβ is only associated with Alzheimer’s disease and Down syndrome. However, studies have shown its involvement in many other neurological disorders. The role of astrocytes in handling the excess levels of Aβ has been highlighted in the literature. Astrocytes have a distinctive function in both neuronal support and protection, thus its involvement in Aβ pathological process may tip the balance toward chronic inflammation and neuronal death. In this review we describe the involvement of astrocytes in Aβ related disorders including Alzheimer’s disease, Down syndrome, cerebral amyloid angiopathy, and frontotemporal dementia.     

A Deterministic Algorithm for Determination of Optimal Water Quality Monitoring Stations

Water quality monitoring networks are usually designed according to statistical approaches and general criteria without a consistent or logical deterministic design strategy. In this research, a deterministic approach for allocating the most sensitive water quality monitoring stations was proposed. This approach was applied on the western part of the Al-Hammar Marsh. Two-dimensional hydrodynamic and water quality simulation models were used to estimate the distribution of total dissolved solids (TDS) within the marsh for all of the expected conditions. Subsequently, the spatial distribution of the variance of TDS was computed based on the results of these models and performed in a Geographic Information System (GIS) database layer. The standard acceptable TDS variation limits of ±5%, land-use map, land-cover map and other main selection criteria of the monitoring stations were set as constraints via GIS database layers. These layers were integrally applied to the variance layer to obtain the locations of the most sensitive monitoring stations. It was concluded that, the most representative monitoring network consists of 46 stations. This number can be reduced to 37 and 29 stations by increasing the acceptable TDS variation limits to ±10% and 15%, respectively. The developed approach can be used with limited data. Moreover, it can be applied to rivers, lakes or wetlands, considering all of the related constraints. In addition, the GIS database can be easily updated and analysed. These features are not available in other methods such as the Sanders method, multiple criteria decision making and dynamic programming approach.     

Multi-Criteria Approach for Evaluating Long Term Water Strategies

Abstract

Long-term national water strategies, which are formulated to cope with the socio-economic development plans, have either positive or negative impacts in several domains including environment, economy, and social life. Intuitive evaluation of policies and actions on the basis of their social, economic, and environmental utilities is ambiguous and very complex. Setting water resources policies for a country like Egypt is a good example of this type of complexity due to its multisectoral, interdisciplinary, interrelated environment. There is a classical assumption in water resources planning and management that stipulates decisions based on optimization of a well-defined single objective. In reality, the decision-making process is much more complex. Decision makers seek an optimal compromise among several objectives or try to achieve satisfying levels of their goals. Therefore, the present study proposes the multi-criteria analysis as an approach for evaluating Egypt's long term plans to reveal their rank and behavior throughout the foreseen planning horizon. Several evaluation criteria (indicators) have been articulated and grouped into four main categories: water, environment, social, and economy. A simple empirical simulation model was used to score different criteria. Four cases have been compared and evaluated by the suggested approach. Each case represents an anticipated national water-related development plan. This is carried out under specific scenarios for uncontrolled variables such as population growth rate, hydrological river flow into the system, and others. The application showed that a multi-criteria approach could contribute significantly to the decision making process in Egypt. It provides a systematic way of presenting the tradeoffs among policy choices considering many issues.     

A multiprocess machine tool for compound micromachining

Compound micromachining is the most promising technology for the production of miniaturized parts and this technology is becoming increasingly more important and popular because of a growing demand for industrial products, with an increased number not only of functions but also of reduced dimensions, higher dimensional accuracy and better surface finish. Compound micromachining processes that combine multiple conventional and non-conventional micromachining processes have the capability to fabricate high aspect ratio microstructures with paramount dimensional accuracy. Such machining should be carried out on the same machine with minimum change of setups. At the same time, on-machine tool fabrication along with on-machine tool and workpiece measurement facilities should also be available for further enhancement of the functionality of the machine and higher productivity. In order to achieve effective implementation of compound micromachining techniques, this research seeks to address four important areas, namely (a) development of a machine tool capable of both conventional micromachining including microturning, micromilling, etc., and non-conventional micromachining including microelectrical discharge machining (micro-EDM), wire-cut electrical discharge machining (WEDM), etc.; (b) process control; (c) process development to achieve the necessary accuracy and quality and (d) on-machine measurement and inspection. An integrated effort into these areas has resulted in successful fabrication of microstructures that are able to meet the miniaturization demands of the industry. This paper presents a few tool-based approaches that integrate micro-EDM, micro-EDG, microturning and microgrinding to produce miniature components on the same machine tool platform in order to demonstrate the capabilities of compound micromachining.     

Gain-bandwidth product optimization of heterostructure avalanche photodiodes

A generalized history-dependent recurrence theory for the time-response analysis is derived for avalanche photodiodes with multilayer, heterojunction multiplication regions. The heterojunction multiplication region considered consists of two layers: a high-bandgap Al/sub 0.6/Ga/sub 0.4/As energy-buildup layer, which serves to heat up the primary electrons, and a GaAs layer, which serves as the primary avalanching layer. The model is used to optimize the gain-bandwidth product (GBP) by appropriate selection of the width of the energy-buildup layer for a given width of the avalanching layer. The enhanced GBP is a direct consequence of the heating of primary electrons in the energy-buildup layer, which results in a reduced first dead space for the carriers that are injected into the avalanche-active GaAs layer. This effect is akin to the initial-energy effect previously shown to enhance the excess-noise factor characteristics in thin avalanche photodiodes (APDs). Calculations show that the GBP optimization is insensitive to the operational gain and the optimized APD also minimizes the excess-noise factor.     

NONISOTHERMAL CHARACTERIZATION OF THIN-FILM OSCILLATING BEARINGS IN THE PRESENCE OF ULTRAFINE PARTICLES

The effects of viscous dissipation and thermal dispersion due to the presence of ultrafine particles in the lubricating fluid are studied on flow and heat transfer inside a non-isothermal and incompressible bearing during relief and squeezing stages. The governing equations are nondimensionlized and reduced to simpler forms based on an order-of-magnitude analysis. Analytical solution for the energy equation for a special case is obtained. Further, the influence of the thermal squeezing parameter, Eckert number, thermal dispersion coefficient, the motion characteristics of an oscillating bearing, and the perturbation parameter are determined. It is shown that the average heat transfer parameter decreases by an increase in the thermal squeezing parameter and dispersion coefficient, while it increases as both the Eckert number and amplitude motion parameter are increased.     

NONISOTHERMAL CHARACTERIZATION OF THIN FILM OSCILLATING BEARINGS

Flow and heat transfer inside a nonisothermal, incompressible, thin-film squeezing bearing are analyzed. The governing equations have been nondimensionalized and reduced to simpler forms based on an order of magnitude analysis. Various analytical solutions for the temperature distribution and Nusselt number under different physical constraints are obtained. The influence of the thermal squeezing parameter as well as the motion characteristics of an oscillating bearing are determined on a Nusselt number analytically and numerically, and, similarly, the Nusselt number history is shown for an oscillating thin-film bearing.