Prediction of zonal and total discharges in smooth straight prismatic compound channels using regression modeling

Experimental results are presented concerning the zonal and total discharge distribution and characteristics in a compound channel cross-section comprising one rectangular main channel and two symmetrical floodplains. The discharges in the main channel, floodplains, and total compound channel are found to be highly correlated to several dimensionless parameters defined using the compound channel cross-section geometry. Multi-variable regression analysis was utilized for developing predictive models that can estimate the main channel, floodplains and total discharges as a function of four different dimensionless parameters. The developed models to predict the zonal and total discharges in compound channels are found to be highly significant according to several major statistics including the model standard error, coefficient of determination (R²), and F-statistic. The developed multi-variable regression-based models are also tested for validity using available experimental data. Several statistical tests applicable to the analysis of residuals have indicated the effectiveness of the developed predictive models.     

Discriminatory processor sharing queues with stationary ergodic service times and the performance of TCP in overload

In a recent paper, Bonald and Roberts (2001) [6] studied non-persistent TCP connections in transient overload conditions, under the assumption that all connections have the same round-trip times. In this paper our goal is to develop theoretical tools that will enable us to relax this assumption and obtain explicit expressions for the rate of growth of the number of connections at the system, the rate at which TCP connections leave the system, as well as the time needed for the completion of a connection. To that end, we model the system as a discriminatory processor sharing (DPS) system which we analyze under very mild assumptions on the probability distributions related to different classes of arrivals: we only assume that the arrival rates of connections exist, and that the amount of information transmitted during a connection of a given type forms a stationary ergodic sequence. We then proceed to obtain explicit expressions for the growth rate of the number of connections at the DPS system for several specific probability distributions. We check through simulations the applicability of our queueing results for modeling TCP connections sharing a bottleneck.     

Carbon footprint evaluation at industrial park level: A hybrid life cycle assessment approach

Industrial parks have become the effective strategies for government to promote sustainable economic development due to the following advantages: shared infrastructure and concentrated industrial activities within planned areas. However, due to intensive energy consumption and dependence on fossil fuels, industrial parks have become the main areas for greenhouse gas emissions. Therefore, it is critical to quantify their carbon footprints so that appropriate emission reduction policies can be raised. The objective of this paper is to seek an appropriate method on evaluating the carbon footprint of one industrial park. The tiered hybrid LCA method was selected due to its advantages over other methods. Shenyang Economic and Technological Development Zone (SETDZ), a typical comprehensive industrial park in China, was chosen as a case study park. The results show that the total life cycle carbon footprint of SETDZ was 15.29 Mt, including 6.81 Mt onsite (direct) carbon footprint, 8.47 Mt upstream carbon footprint, and only 3201 t downstream carbon footprint. Analysis from industrial sector perspectives shows that chemical industry and manufacture of general purpose machinery and special purposes machinery sector were the two largest sectors for life cycle carbon footprint. Such a sector analysis may be useful for investigation of appropriate emission reduction policies.     

Hybrid quality adaptation mechanism for layered multicast over the internet

The use of multicast for distribution of real-time video over the Internet has received greater attention over the past few years. Unfortunately, a major challenge to its wide usage is the heterogeneity of networks and receivers. In this paper we proposed a mechanism called Hybrid Quality Adaptation (HQA) for multicasting layered MPEG-2 video. The receiver will subscribe to the number of layers based on their network and end-system resources. On the other hand, the video server adjusts the transmission characteristics of each layer to try and accommodate the requirements of the majority of the receivers. A prototype layered MPEG-2 multicast system, using HQA, has been successfully developed.     

On the outlook for solar thermal hydrogen production in South Africa

Global warming and tightening environmental legislation is putting pressure on divesting from fossil fuel in the energy sector, with the transport sector likely to see the biggest changes. Current alternative energy sources are electric vehicles and hydrogen. Conventional hydrogen production technologies are fossil fuel based, emitting significant amounts of CO₂ into the atmosphere. This paper explores various ways to integrate solar thermal technologies into hydrogen production to generate carbon free hydrogen in South Africa. South Africa's abundant solar resource indicates that the country may become a significant player in the hydrogen market. However, the high capital cost associated with solar thermal energy put solar thermal hydrogen at a price disadvantage against conventional production technologies. Significant market penetration for solar thermal hydrogen is not expected within the next decade, but cost reduction due to improved manufacturing techniques and larger manufacturing volumes might close the gap in the long term.     

A general framework incorporating knowledge,risk perception and practices to eliminate pesticide residues in food: A Structural Equation Modelling analysis based on survey data of 986 Chinese farmers

Following a variety of incidents in China relating to food poisoning due to the presence of pesticide residues, it is crucial to correct for farmers’ unsafe and improper practices towards pesticide use. Although most studies have focused on the role of external stakeholders such as government extension agencies and pesticide retailers, the attention paid to farmers’ intrinsic motivations is limited. This paper applies Structural Equation Modelling to investigate psychological motivational concepts such as farmers’ knowledge and risk perception, their formation mechanisms and the underlying processes of these concepts that lead to farmers’ practices to eliminate pesticide residues, based on a representative survey conducted with 986 Chinese farmers from 20 counties selected from six provinces. We found both a direct and significant effect of farmers’ knowledge on pesticides residue on their safe pesticide practices and also an indirect effect, i.e. knowledge influences on risk perception which in turn enhances safe pesticide practices. It was also reported that government support strategies are more effective in promoting safe pesticide practices than government regulation.     

Challenges in understanding public responses and providing effective public consultation on water reuse

This paper suggests key challenges facing our understanding of public responses to water recycling and our efforts to provide effective public consultation. The current understanding of public reactions to water recycling is insufficient to predict support in general or for specific schemes, and cannot obviate a thorough investigation and engagement for each proposal. Such support as is evident may not be robust. We need to provide better opportunities and mechanisms, and a wider scope, for community involvement. These entail a broader conception of the information needs of participants, and careful integration of education and consultation processes. Our discussion forms the rationale for a program of research as part of the Oz-AQUAREC project. We propose trialling discourse analysis methods, first, to examine the views expressed in focus groups and try to understand their social bases, and second, to facilitate interactions between technical practitioners, authorities and community groups.     

Stakeholder communications for successful water reuse operations

A well-organised, comprehensive communications program with stakeholders is essential to any modern water reuse project. To maximise trust between water reuse organisations and stakeholders, the communication process needs to begin long before project plans are drawn up and continue throughout the life of any project. It must begin with the decision to seriously consider the development of a scheme and remain highly visible throughout all of its stages, including planning, construction, implementation and operation. The communications program must also embrace any extensions of the project. This paper relates to a study that was undertaken in the preliminary preparation of a manual of best practice for water recycling operations. The purpose of the study was to provide an understanding of major communication issues to be addressed and successful means of addressing them. Ten key messages to stakeholders were established during the process and are presented here.     

Preparing for disruptions: A diagnostic strategic planning intervention for sustainable development

Despite the emphasis on sustainable development in some of the contemporary planning and policy rhetoric, we face an implementation deficit in practice. The impediments to the widespread adoption and successful implementation of sustainable infrastructure in cities' critical sectors—such as water, energy or transport—are varied and complex. Although the scholarship has made some attempts to understand and categorize those impediments, not much has been said about how to identify them in a specific practical context. This study proposes a model for a diagnostic intervention in the ongoing process of strategic infrastructure planning, as a way of revealing context-specific impediments. The diagnostic intervention incorporates an explicit and reflexive consideration of short-term barriers and long-term disruptors into the strategic planning process, and assists with drafting the required coping strategies. The intervention has been tested in water infrastructure planning for one of the world's largest urban renewal areas in Melbourne, Australia. This trial application provided promising outcomes for addressing the implementation deficit of sustainable development: it created a platform for various stakeholder groups to engage in explicit discussions on their confronted problems, which often have trans-organizational causes and impacts; it enabled reflexivity within the ongoing planning process; and, it helped to consider a large portfolio of future uncertainties to provide an enabling condition for more robust decisions to be made. Moreover, the trialed intervention provided empirical evidence in support of the scholarly discourse which contends that sustainable infrastructure delivery is not only about the development of technical solutions, but is also about the development of processes and tools that support the widespread adoption and successful implementation of those solutions in the face of wide-ranging impediments.     

An argument for metropolitan government in Australia

The federal government of Australia seeks to determine the selection and forms of financing of infrastructure projects in cities, and to prescribe how cities are planned and managed. This role is rationalised through reference to the UK City Deals model and is made possible by vertical fiscal imbalance (the tax revenue it raises considerably exceeds its expenditure responsibilities). Referring to the Constitution, this role is assigned to state governments that are responsible for planning, infrastructure investment and service delivery in the cities. The cities themselves comprise multiple local governments that are ‘creatures’ of state government legislation. State government metropolitan strategic plans and projects inevitably serve the interests of the constituencies needed to win the next state elections. There is no recognition of a metropolitan constituency. Documenting the economic and social disadvantages arising from Australia's form of metropolitan governance, and providing an example for expensive infrastructure mishaps arising from federal and state governments prioritising different transport modes and projects, the paper argues for the creation of representative, accountable and fiscally autonomous metropolitan governments.