Performance evaluation of the Walnut Creek ‘soft armor’ lining system

As both cities and erosion control legislation continue to grow, the need for cost effective, high performance channel lining systems is becoming even more important than ever. When the City of Austin, Texas (USA) faced this challenge, lenge, sought to use a soft armor lining in lieu of the specified concrete lining along Walnut Creek Tributary #7, Phase 1. Located in a largely residential neighborhood, the need to provide good aesthetics at a reasonable price was important to the city. Installed in March 1991, roughly up to 11 meters (36 feet) wide and 350 meters (1150 feet) long, the channel lining system has remained in good condition and continues to provide the benefits of a turf reinforced waterway.

This paper provides the background, selection, and long-term performance evaluation of a soft armor channel as an alternative to traditional hard armor. Data from rainfall events is used to estimate velocity and shear stress exerted on the system over the first five years of performance. Included are also photographs, vegetation progression, chronological data, and field observations from the time of installation in 1991 to the present.     

REPORTING AN URBAN ‘BOX SCORE:’ THE JOURNALISTIC ‘SPORTS’ RECORD TO MEASURE LOCAL URBAN PERFORMANCE

For the press to “keep score” on the performance of urban games and players, it should recognize and apply the use of both sports reporting techniques and social indicators in coverage of urban affairs. It should also make a stronger and more reasoned commitment to the local community by re-organization of newsrooms, new definitions of news to fit urban reality, an intelligent check on the urban experts, a provision for “distant-early-warning” news, and abandonment of its journalistic myopia that politics is “bad.”     

Wind turbine drives — Test results from the ‘falcon’

A wind turbine drive has been designed and built for full scale trials in order to assess the use of this type of propulsion for commercial craft. This wind turbine rig is fitted to the 5.6m long Blackwater sloop ‘Falcon’.

Test results from this boat are presented over a range of operating wind conditions up to Beaufort force 6 (11.5m/s) for two different wind turbine rotors. Maximum boatspeeds reached were 3.5 knots upwind (in 7.2m/s wind), 5.0 knots across the wind (9.8m/s wind) and 5.2 knots downwind (8m/s wind). The ‘hull speed’ of this boat is around 5.0 knots.     

The concept of a ‘concentration town’

The Netherlands Habitat Commission was founded to coordinate all activities during the International Year of Shelter for the Homeless (1987). Over the years in the Netherlands, both on the governmental and nongovernmental level, attention to and support for the urban problems in the Third World has significantly increased. The Commission had taken the initiative of developing a so called concentration town project, based on the concept that targeting aid to one city will strengthen the impact of each individual project. A pilot project is being established in the Indian city of Bangalore. The results so far are promising. Through this project the NHC would like to show how use can be made of the growing interest in the plight of the urban poor in the Third World.     

Materials for concrete repair - ‘Innovations’

The realisation that modern concrete structures are not as durable as was anticipated has caused increasing concern among structural design engineers, site contractors and materials' scientists alike.It is accepted that only when the fundamentals of reinforced concrete design and the implications of structural analysis are understood can satisfactory repairs be undertaken to structures suffering from any form of distress. In order to effect successful repairs, the same degree of professional expertise as the original design required is necessary.     

New ‘rural lifestyle estates’ in The Netherlands

Recent studies tend to indicate that no longer all presently agricultural land in The Netherlands is required for sustainable agricultural production. Apart from various urban uses and some projects turning agricultural land into nature reserves or giving it a secondary function, like national landscape parks or drinking water supply area, it is not easy to find alternative users for the land presently managed by farmers. At the same time, many urban companies or families are vainly looking for building lots away from our ‘compact urban areas’. This paper explores a way to bring this supply and demand together in a landscape-wise more than acceptable manner: the planning concept and experiment of ‘new rural lifestyle estates’.     

Implementation of improved wetland systems as a ‘zero‐discharge‐technology’ in Poland

This paper discusses results from the implementation of a ‘zero‐discharge‐ technology’ primarily for single households, as well as hotels and small residential urban and rural areas. During a 15‐year span, 5600 improved wetland systems (IWS) were built, and approximately 50% of treatment wetlands in Europe are located in Poland. The first section of this paper discusses water and wastewater management and its development trends. Particular attention is paid to creating sustainable water management in rural areas due to increased necessity in these regions. The second section presents the principle of the IWS, which consists of two options. The third section discusses the current requirements regarding the quality of treated wastewater in Poland. The fourth section presents the effectiveness of the implementation of this system by the Institute for Applied Ecology and the further prospects of ‘zero‐discharge‐technology’ development. The last section discusses the obtained results in the reduction of pollution.     

Why does ‘good ecological status’ matter?

Achievement of ‘good ecological status’ under the EU Water Framework Directive (WFD), and various ‘environmental outcomes’ under other legislation and strategies, are accepted as important by environmental interests. However, support from the wider public may be largely altruistic. ‘Ecosystem services’ can better relate ecosystem health to societal benefits, helping communicate the advantages of achieving good status and securing support for environmental priorities. A series of ecosystem services case studies provides lessons about promoting public understanding of the benefits of achieving environmental targets. Framing desired WFD goals in terms of ecosystem service outcomes can optimise societal benefits proved by ‘programmes of measures’ and avert unintended consequences, compared with traditional, discipline‐specific management approaches. It can also highlight potential contributions from ecosystem‐based technologies to achieving multiple benefits across ecosystem service categories. ‘Siloed’ institutions and budgets are likely to perpetuate fragmented approaches unless explicit measures are taken to achieve more systemic outcomes.     

On Hotelling's ‘stability in competition’ with network externalities and switching costs

We revisit the Hotelling duopoly model with linear transportation costs, introducing network effects and brand loyalty. We show that, while network externalities destabilize prices, the lock‐in effect generated by exogenous switching costs, if sufficiently high, eliminates the incentive to undercut, thereby restoring the existence of the pure strategy equilibrium in prices, and the corresponding minimum differentiation principle.     

‘Management by projects’: the management approach for the future

The trend toward the project-oriented company, performing simultaneously a network of internal and external projects, creates the demand for the management approach ‘Management by Projects’. The specific feature of ‘management by projects’ is that the management of single projects, the management of the network of projects and the management of the relationships between the company and the single projects are considered. For the successful management of the project-oriented company, instruments of ‘Management by Projects’ are presented.     

Improving the interpretation of ‘less than’ values in environmental monitoring

This paper reviews the approaches used to deal with the interpretation of measurements reported as ‘less than’ a stated reporting limit. The principal current methodologies are examined and their shortcomings discussed. Recent key papers on the subject are summarised. It is concluded that lack of easy‐to‐use alternative methods have led to the continued use of substitution methods that are acknowledged to be biased. With the aim of promoting a more technically sound approach to dealing with ‘less than’ data, a supplementary spreadsheet tool is supplied to provide the reader with ready introductory access to a simple way to apply maximum likelihood methods. Recommendations and simple guidelines for better practice are provided.     

GBT formulation to analyse the buckling behaviour of thin-walled members with arbitrarily ‘branched’ open cross-sections

This paper presents the derivation, validates and illustrates the application of a Generalised Beam Theory (GBT) formulation developed to analyse the buckling behaviour of thin-walled members with arbitrarily ‘branched’ open cross-sections. Following a brief overview of the conventional GBT, one addresses in great detail the modifications that must be incorporated into its cross-section analysis procedure, in order to be able to handle the ‘branching’ points — they concern mostly issues related to (i) the choice of the appropriate ‘elementary warping functions’ and (ii) the determination of the ‘initial flexural shape functions’. The derived formulation is then employed to investigate the local-plate, distortional and global buckling behaviour of (i) simply supported and fixed asymmetric E-section columns and (ii) simply supported I-section beams with unequal stiffened flanges. For validation purposes, several GBT-based results are compared with ‘exact’ values, obtained by means of finite strip or shell finite element analyses.     

Seismic analysis of the ‘South Gate’ tall building according to Eurocode 8

The tallest building designed in Poznań (western part of Poland) is the case study. The analysed building is a multifunctional office centre with the heliport on the top, called the ‘South Gate’. The main structure is the RC slab and column system with shear walls and cores. After many static analyses the seismic analysis, based on damage limitation state according to Eurocode 8, was made. The analysis, in which a continuous–discrete approach and the response spectrum technique were applied, was carried out by means of the DAMB program as part of an integrated system. The allowable design ground acceleration was evaluated. Copyright © 2004 John Wiley & Sons, Ltd.     

The application of ‘least-cost’ modelling as a functional landscape model

The growing awareness of the adverse effects of habitat fragmentation on natural systems has resulted in a rapidly increasing number of actions to reduce current fragmentation of natural systems as well as a growing demand for tools to predict and evaluate the effect of changes in the landscape on connectivity in the natural world. Recent studies used ‘least-cost’ modelling (available as a toolbox in GIS-systems) to calculate ‘effective distance’, a measure for distance modified with the cost to move between habitat patches based on detailed geographical information on the landscape as well as behavioural aspects of the organisms studied. We applied the method to a virtual landscape and a small scaled agricultural system subject to different scenarios in a land re-allotment project. We discuss the importance of technical aspects and ecological assumption underlying this modelling method. The model is shown to be a flexible tool to model functional connectivity in the study of the relation between landscape and mobility of organisms as well as in scenario building and evaluation in wild life protection projects and applied land management projects. Since ‘effective distance’ has the same units as Euclidean distance (m), this effective distance may be a straightforward way to include landscape and behavioural aspects in other models which include distance as a measure for isolation. We show the importance of the ‘ecological’ quality of the input maps and the choice of relevant landscape features and resistance values.