How do we know when we have done enough to protect the environment?

The changing concepts and challenges that the process industry has to face in relation to environmental protection are discussed. The original requirements on industry to reduce emissions of contaminants through the installation of filters and waste water treatment facilities or through process modification and introduction of ‘clean production’ strategies were mainly based on economic and technical considerations rather than on an effort to avoid environmental impacts. The introduction of concepts such as ‘assimilative capacity of the environment’ and ‘critical load’ provided useful instruments for setting effect-related emission standards, resulting in acceptable environmental protection. However, the actual requirement for ‘sustainability’ has forced industry to focus not only on controlling emissions of contaminants and pollutants, but to take a global environmental approach, including the choice of raw materials and energy sources, recycling and re-utilization of wastes and to take responsibility for the fate of their products, during their whole lifecycle.     

Geological mapping of rapid mass movement deposits as an aid to land-use planning

Rapid mass movements are common features of hilly or mountainous terrains, and depending on the type of movements or processes involved these give rise to characteristic deposits. Identification of these deposits in mapping programmes gives a clue as to their mode of origin (rockslide/rockfall, snow avalanche, debris flow, fluidal sediment flow) and this can be used to predict rapid mass movements in the future.

A case story from western Norway is described and the value of mapping such deposits for land-use planning and hazard estimation stressed.     

Suspension and calibration of a sediment trap

The aim of this technical note is to introduce a new, simple construction of a buoy-carried, suspended sediment trap that meets given demands concerning design (geometry of vessels) and stability during the registration period. The device is based on a ball-and-socket joint in the center and two Plexiglas cylinders (D=5cm, H=30cm) on PVC plastic arms. The suspension consists of only three parts. To determine the optimal construction, the apparatus has been calibrated in a circulating flume at various water velocities.     

Impedance of flexible suction caissons

The dynamic response of offshore wind turbines is affected by the properties of the foundation and the subsoil. The aim of this paper is to evaluate the dynamic soil–structure interaction of suction caissons for offshore wind turbines. The investigations include evaluation of the vertical and coupled sliding–rocking vibrations, influence of the foundation geometry and examination on the properties of the surrounding soil. The soil is simplified as a homogenous linear viscoelastic material and the dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequency‐dependent coefficients corresponding to different degrees of freedom. The dynamic stiffness coefficients for the skirted foundation are evaluated using a three‐dimensional coupled boundary element/finite element model. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviours of the foundation are predicted accurately using the applied model. The analysis has been carried out for different combinations of the skirt length, Poisson's ratio of the subsoil and the ratio of the soil stiffness to the skirt stiffness. Copyright © 2007 John Wiley & Sons, Ltd.     

Climate sensitivity to wetlands and wetland vegetation in mid-Holocene North Africa

 Wetland regions are important components of the local climate, with their own characteristic surface energy and moisture budgets. Realistic representation of wetlands, including the important vegetation component, may therefore be necessary for more accurate simulations of climate and climate change. However, many land-atmosphere coupled models either ignore wetlands or treat wetlands as bare, water-saturated soil, neglecting the vegetation present within wetland environments. This study investigates the possible response of the mid-Holocene climate of North Africa to changes in orbital forcing, both with and without the presence of wetlands. The location of these wetlands is guided by analysis of paleovegetation and wetland distribution. In this study, the wetland regime in the land surface component of a climate model was modified to incorporate vegetation. Field measurements have shown that vegetation affects water loss associated with evaporation (including transpiration) within a wetland area. Comparisons between non-vegetated wetland and vegetated wetland revealed an increase in local albedo that produced an associated decrease in net radiation, evaporation and precipitation in the vicinity of the wetlands regions. Based on an analysis of the model surface water balance, the calculated area of mid-Holocene wetland coverage for North Africa closely matches the observed. For the North African region as a whole, the effects of adding vegetation to the wetland produced relatively small changes in climate, but local recycling of water may have served to help maintain paleo wetland communities. Received: 16 March 1999 / Accepted: 17 May 2000     

A study of apparently nearby stars with coinciding spectral type and apparent magnitude

At visual inspection of objective-prism plates one frequently detects a pair or higher multiple of apparently identical stellar spectra so close together that they form a conspicuous configuration for the eye. An attempt to analyse this type of objects has given no positive indication that it should be identified with any unique physical phenomenon. A series of explanations is presented. A minor fraction of the objects may constitute widely separated binary components, the identity of which is physically conditioned by the process of formation. For the majority, however, it seems more probable that they form parts of cluster remnants or very small clusters, and that the coincidence of the spectral types is in the first instance to consider as a fortunate random effect that facilitates the detection of the hidden cluster. Although there are several interpretations of the appearance of such ‘miniclusters’, I find it particularly important to take the possibility into consideration that the number of open clusters (and associations) may be considerably greater than one has hitherto assumed—from observational as well as from theoretical point of view.     

Chemical Mechanism Development: Laboratory Studies and Model Applications

Within the German Tropospheric Research Programme (TFS) numerous kinetic and mechanistic studies on the tropospheric reaction/degradation of the following reactants were carried out: oxygenated VOC, aromatic VOC, biogenic VOC, short-lived intermediates, such as alkoxy and alkylperoxy radicals.At the conception of the projects these selected groups were classes of VOC or intermediates for which the atmospheric oxidation mechanisms were either poorly characterised or totally unknown. The motivation for these studies was the attainment of significant improvements in our understanding of the atmospheric chemical oxidation processes of these compounds, particularly with respect to their involvement in photooxidant formation in the troposphere. In the present paper the types of experimental investigations performed and the results obtained within the various projects are briefly summarised. The major achievements are highlighted and discussed in terms of their contribution to improving our understanding of the chemical processes controlling photosmog formation in the troposphere.     

Lumbering operations,lake humification and consequences for the structure of the lake foodweb: A case study using the LakeWeb-model for Lake Stora Kröntjärn,Sweden

This work presents a scenario to demonstrate how a given lake (Lake Stora Kröntjärn, Sweden) would respond to changes in colour related to lumbering operations in its watershed. The questions posed are: How would lake colour values increase, for how long would such increases last and how would this influence the production and biomasses of key functional organisms in the lake? The work is based on a comprehensive lake ecosystem model, LakeWeb, which accounts for production, biomasses, predation, abiotic/biotic interactions of nine key functional groups of organisms, phytoplankton, bacterioplankton, two types of zooplankton (herbivorous and predatory), two types of fish (prey and predatory), as well as zoobenthos, macrophytes and benthic algae. The LakeWeb-model has been calibrated and critically tested using empirical data and regressions for many lakes and it can capture typical functional and structural patterns in lakes. To obtain results like these by traditional field-work in one or more lakes would be very demanding (in terms of money, persons and time). It has been shown that single tributary peaks in colour concentrations are often "drowned" in weekly mean lake values. The lumbering operations must be extensive and continue for a long time to cause significant increases in tributary colour values in order to significantly influence fundamental lake foodweb structures. This means that it is often realistic to assume that lumbering activities do not strongly influence lake foodweb structures. The LakeWeb-model with the given mass-balance model for lake colour can be a useful tool to assess situations when this might not be valid.