Greenways: multiplying and diversifying in the 21st century

Building on the legacy of historic greenway planning in the U.S., several new initiatives have been taking shape and gaining recognition in the past decade. One is ‘Green Infrastructure’ planning which is a ‘must have’ inter-connected system of green spaces. Another is ‘Smart Conservation’—the counterpoint of another planning initiative that preceded it known as ‘Smart Growth’. This is the establishment of critical green corridors that should be preserved and maintained for predominantly ecological functions, in advance of or in conjunction with new development. ‘New Urbanism’ has focused on bringing order and coherence to escalating ‘Edge Cities’ on the urban fringe, based on walkable, mixed-use towns, villages and neighborhoods with integrated open-space systems. Transit-Oriented Developments (TODs) are transportation plans for accommodating regional growth around clustered ‘pedestrian pockets’ linked by transit systems. Both New Urbanism and TODs have applied similar principles to ‘brown sites’ and declining city neighborhoods.All these initiatives are different aspects of the greenway movement, expressing its many possibilities, enriching its original concepts, enlarging its credibility—if need be—and emphasizing its importance for and relevance to current issues of sustainability and ‘green’ planning and design. The author, a teacher/practitioner, discusses recent U.S. greenway examples at site, metropolitan and regional scales for which he has been the principal planner/designer or a consultant, and compares New Urbanism and TOD methodologies and approaches to established greenway-planning practices and the premises of Smart Conservation.     

The many faces of planning

In this issue of Bookwatch, we start with a number of books which deal with different aspects or approaches to planning. The first has an unusual title (particularly for a book from the US): Planning in Government: Shaping Programs that Succeed (by Melvin R. Levin, Planners Press, Chicago, 1987, 257 pp). The idea that planning can ‘succeed’ is not all that common these days, and one might expect this volume to take the nature of a political tract, bucking the current strong anti-government, pro-privatism philosophies, and espousing the benefits of more — or at least better — planning.     

Greenways for recreation and maintenance of landscape quality: five case studies in Portugal

The use of the concept of greenway can be identified in Portugal throughout the 20th century as a planning and design tool. Several examples, such as the ‘Improvement Plans for Lisbon’ by Ressano Garcia (1901), the continuum naturale concept [Cabral, F.C., 1980. O Continuum Naturale e a Conservação da Natureza. Conservação da Natureza. Serviço de Estudos do Ambiente, Lisbon; Andresen, T., 2001. Francisco Caldeira Cabral. Landscape Design Trust, Surrey, UK, 213 pp.], the Green Plan for Lisbon [Telles, G.R., et al., 1997. Plano Verde de Lisboa. Ed. Colibri, Lisboa, 197 pp.], deal with the subjects of implementing vegetation corridors, pedestrian networks and landscape quality. These examples establish Portuguese planning and design tradition within the international greenway movement first identified by Fabos [Fabos, J.Gy., 1991. From Park to Greenways into the 21st Century. In: Proceedings from Selected Educational Sessions, ASLA Annual Meeting, Kansas City, Missouri]. Though several projects have been developed at the planning level, there is a need to analyze the applicability of such a concept at the regional, municipal and local level. We must consider the characteristics of Portugal's cultural landscape, recognition by other professions dealing with planning and involvement by politicians. By analyzing five case studies, this paper shows the significance of the greenway as a planning and design strategy, which coincides, with the current objectives of political and planning authorities at the municipal level. It also proves that it is possible to reconcile political objectives and urban development while safeguarding landscape quality and providing new opportunities for public recreation and education. Greenway planning and design is now undoubtedly a subject of growing significance in Portugal.     

The importance of ‘process’ in Rethinking Project Management: The story of a UK Government-funded research network

This paper tells the story of a UK Government-funded research network called Rethinking Project Management, funded by the Engineering and Physical Sciences Research Council between 2004 and 2006. The story is significant because of the considerable attention given to the process of the Network, both the inquiry process of ‘rethinking’ project management, and the broader social process in which the rethinking activity was carried out. In telling this story, the lead organisers explain how the inquiry process was organised as a learning system to enable the Network to ‘learn’ its way to relevant directions for future research, and secondly, how the broader social process was organised and facilitated to create a context for effective interaction between the people involved. A significant challenge in managing the research programme was how to engage the participants in purposeful inquiry, which would serve not only the primary aims of the Network, but would also yield new and interesting insights for the people involved. This paper seeks to explain how the lead organisers addressed this challenge, through a detailed and reflective discussion of how the research programme was organised and facilitated to achieve the Network’s primary aims. In summary, the principal aim in telling this story is to highlight the importance of process in collaborative research activity involving academics and practitioners, in order that other researchers might draw on the experience of this Network.     

Evaluation of an attempt to cultivate shrubs and trees on a heap of a potash mine

Starting at the end of November 1993, the Dr. Kahl GmbH has attempted to grow shrubs (Amorpha: Amorpha fructuosa and snow-berry: Symphoricarpos rivularis) and trees (poplar hybrid ‘University of Idaho’ Populus deltoides and Eleagnus angustifolia), on the heap of the potash mine Sondershausen/Harz (Free state of Thuringia). Patented water-saving planting method was used. A flexible planting container made of polyethylene was first filled with 50 g polyacrylamide (also called ‘hydrogel’) and after that with about 40 kg of a mixture of anhydrite (CaSO₄) — the mean soil of the heap — and dried sewage sludge, respectively, composted sewage sludge on top of the hydrogel. After placing the container into the ground, one-year-old seedlings of the shrubs or trees were planted into the containers. Five years after planting investigations on the plants and soil were started. The results until now show that, using the planting method, Amorpha, the poplar ‘University of Idaho’ and the Eleagnus are able to grow under the poor conditions of the heap.     

Numerical and experimental investigations of the response of aluminum cylinders with a cutout subject to axial compression

Understanding how a cutout influences the load bearing capacity and buckling behavior of a cylindrical shell is critical in the design of structural components used in automobiles, aircrafts, and marine applications. Numerical simulation and analysis of moderately thick and thin unstiffened aluminum cylindrical shells (D/t=45, 450 and L/D=2, 5, 10), having a square cutout, subjected to axial compression were systematically carried out in this paper. The investigation examined the influence of the cutout size, cutout location, and the shell aspect ratio (L/D) on the prebuckling, buckling, and postbuckling responses of the cylindrical shells.An experimental investigation on the moderately thick-walled shells was also carried out. A good correlation was observed between the results obtained from the finite element simulation and the experiments. Furthermore, empirical equations, in the form of a ‘buckling load reduction factor’ were developed using the least square regression method. These simple equations could be used to predict the buckling capacities of several specific types of cylindrical shells with a cutout.     

A mixing‐length‐scale‐based analytical model for predicting velocity profiles of open‐channel flows with submerged rigid vegetation

In open‐channel flows with submerged vegetation, the vertical velocity profile can often be described by two layers: the vegetation layer in the lower region and the surface layer in the upper non‐vegetated region. In this paper, a new mixing‐length scale of eddy is proposed for predicting the vertical velocity profile of flow in an open‐channel with submerged rigid vegetation. The analytical model of velocity profile is based on the momentum equation of flow where the turbulent eddy viscosity is assumed to have a linear relationship with the local velocity. The proposed model was tested against different datasets from the literature. The 22 datasets used cover a range of submergence [flow depth (H)/vegetation height (h) = 1.25 ~ 3.38], different vegetation densities of ah = 0.11 ~ 1.85 (a defined as the frontal area of the vegetation per unit volume) and bed slopes (S_o = 1.8 × 10^?6 ~4.0 × 10^?3). This study showed that the proposed model can predict the velocity profiles well against all datasets, and that the mixing length scale of eddies (λ) is well related with both vegetation height (h) and flow depth of surface layer (i.e. the height of non‐vegetation layer, H–h). Close examination of λ in the proposed model showed that when λ = 0.03, the model predicts vertical velocity profiles well for all datasets used except for very shallow submergence (i.e. H/h < 1.5).     

An incubator method for estimating the actual daily planktonalgae primary production

Based on the knowledge of the sun/shade adaptation mechanism of algae a computer program has been developed which makes it possible to transform potential estimated primary production values to ‘normal’ daily primary production values. The potential production is measured in an incubator at a temperature equal to that at the sampling locality. Necessary light energy is delivered by fluorescence lamps (Philips TL 20 W/33). The transformation calculations are based on the actual transmission of green light and the light conditions during a ‘normal irradiance year’. This means that the determined production values represent the ‘normal’ production and thus the eutrophic state of the water body. An intercalibration with the traditional in situ method shows good agreement. If an incubation period of half a light day is used with the in situ method then the method described in this paper is less time consuming.     

The aggressive–cooperative drivers of construction contracting

Construction contracting parties can take either a cooperative or aggressive stance in pursuing their goals. This paper aims at identifying the stimuli (known as drivers) that motivate cooperative or aggressive moves in construction contracting behavior (CCB). In this regard, a three-stage research work has been designed for the completion of the research objective. Based on literature reviews, aggressive and cooperative drivers were identified in the first stage. A questionnaire was designed to collect construction case-specific data on these drivers. Next, taxonomies of aggressive and cooperative drivers were developed by the use of principal component factor analyses (PCFA). A total of three and seven taxonomies for aggressive and cooperative drivers were identified respectively. These taxonomies enable the understanding of aggressive-cooperative nature of CCB in a more amenable and logical manner. With these taxonomies, factor scales were calculated to represent the relative importance of the respective taxonomies. The degree of significance of each factor scales was then evaluated in the third stage. The results showed that the most important cooperative taxonomy is ‘openness of contracting parties’, while the most important aggressive taxonomy is ‘goal oriented’. The findings also suggest that construction projects may not be inherently adversarial. Contract with equitable risk allocation and open discussion of problems would provide the platform for team building so that relationship among contracting parties can be maintained.     

A relict of vegetational landscape related to seasonal migratory grazing in the south of Italy: the ‘Bosco dell'Incoronata’ (Foggia) southern Italy

In the past transhumance of sheep was an important phenomenon which took place all over the territories of central and southern Italy. The flocks, which in summer were pastured in the mountains of the central Apennines, in winter were moved across an intricate network of tracks (called ‘Tratturi’ in Italian) to the lowlands of the Adriatic cost and the plains of Puglia. As a result of a crisis this type of sheep-rearing is disappearing as well as the characteristics of the landscape which resulted from these journeys. We examine what remains of the characteristics of the landscape and vegetation of the ‘Bosco dell'Incoronata’ one of the last winter pastures of Puglia.     

Influence sur la cinetique biochimique de la concentration en carbone organique a l'entree d'un reacteur developpant une polyculture microbienne en melange parfait

Experiments were run in order to determine microbial growth kinetics of a mixed culture in a continuous stirred tank reactor using a multicomponent substrate. Analysis of the results indicated that effluent concentration does not depend only on the dilution rate but also on the concentration of substrate in the influent. A kinetic equation has been established using total organic carbon as a pollution indicator: k = k_o(S/S + αS_o)     

A comprehensive study on the biological treatabilities of phenol and methanol—I. Analysis of bacterial growth and substrate removal kinetics by a statistical method

An unbiassed statistical method was developed to evaluate kinetic parameters in the biological oxidation of wastewaters. Through the statistical analyses of the biological oxidation kinetics, it was shown that the kinetic equations satisfactorily described the bacterial growth and substrate removal kinetics where X is biomass concentration, S is substrate concentration, t is time, a is cell yield coefficient, k_d is cell decay coefficient, K_s is Michaelis-Menten constant, and k is substrate removal rate coefficient. The coefficients K_s and a changed with temperature insignificantly while k and k_d were closely related to it. The temperature independent coefficients K_s and a were estimated to be 236 mg 1⁻¹ (standard deviation, σ = 70 mg 1⁻¹) and 1.21 (σ = 0.06) respectively for phenol, and 2330 mg 1⁻¹ (σ = 1410 mg 1⁻¹) and 1.25 (σ = 0.45) respectively for methanol based on total organic carbon (TOC) and volatile suspended solids (VSS). The oxygen utilization rate can be formulated as where Rr is the oxygen utilization rate (mg 1⁻¹ O₂ time⁻¹), as′ is a coefficient designating oxygen requirement per substrate utilized, and b′ is a coefficient designating oxygen requirement per biomass for endogeneous respiration. The coefficient a′ was 1.39 for phenol and 2.23 for methanol, and b′ was 1.42 k_d for both substances based on TOC and VSS.     

Requirements for accurate quantification of self-affine roughness using the roughness–length method

Self-affine fractals have the potential to represent rock joint roughness profiles. Fractional Brownian profiles (self-affine profiles) with known values of fractal dimension, D, input standard deviation, σ, and data density, d, were generated. For different values of the input parameter of the roughness–length method (window length, w), D and another associated fractal parameter A were calculated for the aforementioned profiles. The calculated D was compared with the D used for the generation to determine the accuracy of calculated D. Suitable ranges for w were estimated to produce accurate D (within ±10% error) for the generated profiles. The results showed that to obtain reliable estimates for fractal parameters of a natural rock joint profile, it is necessary to choose a unit for the profile length to satisfy a data density (d) greater than or equal to 5.1. For roughness profiles having 5.1≤d≤51.23 and 1.2≤D≤1.7, w values between 2.5% and 10% of the profile length were found to be highly suitable to produce accurate fractal parameter estimates. It is recommended to use at least seven w values between the estimated minimum and maximum suitable w values in estimating fractal parameters of a natural rock joint profile. It was found that σ and a global trend of a roughness profile have no effect on calculated D. The estimated A was found to increase with both D and σ. The parameter D captures the auto-correlation and A captures the amplitude of a roughness profile at different scales. Therefore, the parameters D and A are recommended to use with the roughness–length method in quantifying rock joint roughness. In addition, at least one more parameter is required to quantify the global trend of a roughness profile, if it exist; in many cases just the inclination or declination angle of the roughness profile in the direction considered would be sufficient to estimate the global trend. Calculated cross-over lengths (segment length of a profile at which a self-affine profile becomes self-similar) for the profiles investigated were found to be extremely small (less than 0.6% of the profile length) indicating that laser profilometers are required to make roughness measurements at interval lengths comparable to the cross-over lengths of the natural rock joint profiles. To calculate rock joint roughness parameters accurately using the self-similar techniques, it is necessary to have roughness measurements made at interval lengths comparable to the cross-over length of the profile. This indicate clearly the difficulty of using self-similar techniques such as the divider method in estimating rock joint roughness accurately.     

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.     

Israel: metropolitan integration or ‘fractured regions’? An alternative perspective

This paper proposes an alternative account of the high degree of power centrality in Israel, by arguing that the territorial ‘fracturing’ of Israel's main social and ethnic groups has prevented the emergence of effective pressure for regional devolution. Israel's character as a settler and settling state, and its central project of Judaising contested territories, enabled the Israeli ‘ethnocracy’ and its (mainly Ashkenazi) elites to create a political geography of ‘fractured ethnic and social regions’. This was achieved by dispersing minorities and legitimising segregation and inequality, all in the name of the ‘national interest’.The Israeli political landscape is therefore organised as ‘fractured regions’, each representing a distinct and interconnected, yet geographically dispersed, set of localities. The logic of dispersal and segregation, in turn, has also influenced patterns of development and residential separation within Israel's main urban areas. Thus ethnic and social fragmentation and conflict, and not a putative process of national or metropolitan integration, can explain much of Israel's highly centralised power structure.     

‘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.     

Flow-induced vibrations of two circular cylinders in tandem arrangement. Part 1: Characteristics of vibration

This paper presents the results of an investigation on the flow-induced vibration characteristics of two circular cylinders in tandem arrangement, with L/D=0.1–3.2 and reduced velocity U_r=1.5–26, where L is the gap spacing between the cylinders and D is the cylinder diameter. The cylinder vibration was restricted to a plane normal to the incident flow. Three different experimental conditions were examined: (i) both cylinders were allowed to vibrate; (ii) the downstream cylinder only was allowed to vibrate with the upstream cylinder fixed; and (iii) the upstream cylinder only was allowed to vibrate with the downstream cylinder fixed. Five Regimes I–V were identified, depending on L/D, fluctuating lift forces and vibration characteristics of the cylinders. In Regimes I (0.1≤L/D<0.2) and IV (2≤L/D<2.7), the cylinder vibration is absent. In Regime II (0.2≤L/D<0.6), both cylinders vibrate violently for U_r>6, including a divergent vibration of the upstream cylinder. In this regime, the vibration amplitude of the downstream cylinder is strongly dependent on whether the upstream cylinder is vibrating or fixed, whereas that of the upstream cylinder is weakly dependent on the downstream cylinder. In Regime III (0.6≤L/D<2), the convergent vibrations of the two cylinders occur at and around U_r≈6.7. In this regime, the upstream cylinder vibration is completely suppressed when the downstream cylinder is fixed, but the downstream cylinder vibration is almost independent on the upstream cylinder. Regime V corresponds to L/D≥2.7, where the two cylinders are separated sufficiently far, thus each vibrating like an isolated cylinder at and around U_r≈6. In this regime, the downstream cylinder vibration is strongly dependent on the upstream cylinder, but the upstream cylinder vibration is almost insensitive to the downstream cylinder condition.     

Effect of visitors’ pressure on soil and vegetation in several different micro-environments in urban parks in Tel Aviv

The effect of the pressure imposed by visitors on urban soil and herbaceous vegetation was investigated in seven micro-environments in parks in Tel Aviv. Soil properties (organic matter content, soil moisture, soil surface compaction/penetration depth), litter biomass, and herbaceous vegetation characteristics (vegetation cover, number of species, height) were determined in seven micro-environments: oak and pine trees, each under high and under low visitors’ pressure; a herbaceous area without visitors’ pressure; paths; and a resting area. Soil samples were collected from the upper 0–5 cm soil depth. In addition, in the tree micro-environments soil samples were taken at 0.5, 1, 2, and 3 m from the tree trunk. Averages and variances of soil properties and the vegetation characteristics varied among the various micro-environments and according to visitors’ pressure. Soil organic matter and soil moisture contents were significantly higher under oak trees with low visitors’ pressure than in other micro-environments. Litter biomass and penetration depth significantly decreased with increasing visitors’ pressure under pine and, especially, oak. The vegetation cover, number of species, and height of herbaceous vegetation were greatest in the herbaceous area, lower under with the trees where there was high visitors’ pressure and lowest in paths and resting areas. Thus, the soil properties in the oak micro-environment and the vegetation characteristics in the herbaceous area were the most sensitive to visitors’ pressure. For each tree and open area, increasing visitors’ pressure was accompanied by increasing spatial homogeneity of soil and vegetation. A radial spatial pattern of soil properties developed under oak with low visitors’ pressure.