Understanding the role of chronic environmental disturbance in the context of island biogeographic theory

Island biogeographic theory offers a powerful conceptual framework for understanding and managing insular diversity. The human impact on insular environments is constantly growing, especially because of tourism. We performed a simulation study aimed at improving the understanding of the role of disturbance in islands. We also built an individual-oriented computer model of an archipelago subjected to chronic disturbance of varying degree. Results are discussed in the light of island biogeographic theory. Relevant results show the importance of autoecological characteristics of the species considered, regarding the attainment of equilibrium and the species-area relationship in both disturbed and undisturbed cases. The possibility of bias in the predictions of the equilibrium model is pointed out. Fundamental criticisms concerning the ecological relevance of the equilibrium theory are discussed.     

What are expert systems and how can they contribute to Planning?

The possible role of computer‐based expert systems in town and country planning has yet to be formalised and many planners are not aware of the potential and limitations of software developments in this area. This paper defines expert systems for planners, explains their operation and outlines a possible area, within the development control process, where such systems could provide a beneficial contribution to planning.     

Feedstock recycling from plastic and thermoset fractions of used computers (I): pyrolysis

The increasing production of computers, the progress in their performance, and the shorter time between innovation and production has led to increasing numbers of obsolete products. It has thus become necessary to recover some materials from old computers and to protect the environment from a new type of pollution. Such recycling is difficult because of the diversity of polymeric materials used, e.g., thermoplastics (polystyrene or acrylonitrile-butadiene-styrene) and thermosets (epoxy resins), and the relatively high levels of flame retardants (halogen- and nitrogen-containing compounds) added during production. Pyrolysis seems to be a suitable way to recover materials and energy from such waste without component separation if an efficient method for reducing toxic compounds can be applied. In this study, the pyrolysis of plastic and thermoset fractions (keyboards, casings, printed circuit boards, and mixtures thereof) of used computers was studied by thermogravimetry and batch reactor pyrolysis. The degradation products were separated into three fractions, solid, liquid, and gaseous, each of them being characterized by suitable methods such as gas chromatography (GC-MSD, gas chromatography-mass spectrometry detection; GC-AED, gas chromatography-atomic emission detection), infrared (FT-IR) and 1H-NMR (nuclear magnetic resonanace) spectroscopy, and elemental analysis. It has been established that most of the halogens, nitrogen, and sulfur is concentrated in the residue. However, the elimination of hazardous toxic compounds, mainly those containing bromine, is necessary before being able to safely use the pyrolysis oils as fuels or in refinery or petrochemical industry flows.     

Prediction and minimization of vertical migration of DNAPLS using surfactant enhanced aquifer remediation at neutral buoyancy

Surfactant enhanced aquifer remediation (SEAR) had previously been thought to require a capillary barrier below the contaminated zone to prevent the vertical migration of a microemulsion containing solubilized DNAPL. This paper shows the vertical migration of the dense microemulsion is described and predicted by the value of three dimensionless scaling groups. Embedded within these scaling groups are four design parameters. The value of these parameters can be manipulated in order to reduce the amount of vertical migration anticipated for a given remediation design. Plots have been constructed that illustrate the relationship between vertical migration and the value of the scaling groups; such plots can be used to predict vertical migration and to determine appropriate screen intervals of extraction wells to ensure full capture of the contaminants. This predictive capability has been verified in laboratory experiments. Predicted migration of the microemulsion agreed within about 2% of that observed. Development of the scaling groups is presented, remediation design implications are discussed, and laboratory verification is shown. Additional discussion of the laboratory work is given in a companion paper [Kostarelos, K., Pope, G.A., Rouse, B.A., Shook, G.M., 1998. A new concept: the use of neutrally-buoyant microemulsions for DNAPL remediation, J. Contam. Hydro., this edition].     

Evolutionary cause of the vulnerability of insular communities

Communities on oceanic islands are considered to be vulnerable to biological invasion. However, because the detailed structures of such communities have not yet been revealed, the relationship between their vulnerability and structure is not clear. Because such communities evolved without biological invasion, they are expected to have structures different from those of mainland communities, and this difference is expected to affect their vulnerability to invasion. I conducted computer simulations based on a food web model and investigated the difference in structure between mainland and insular model communities, the former of which evolved with frequent invasion and the latter without invasion. In addition, by conducting computer simulations of invasion of these model communities, I investigated the relationship between community structure and vulnerability to biological invasion. The insular model community evolved to have an unstable structure, in that a small number of plant species supported a large number of animal species, and each species in the community had a small biomass. When a plant species invaded and disturbed the base of the insular model community, many animal species relying on the plants easily became extinct. In addition, when a carnivorous species invaded, animal species with small biomass tended to become extinct. Community collapses caused by biological invasion occurred more frequently in the insular model community than in the mainland model community. These results indicated that those communities that evolved without invasion were vulnerable to invasion. The available data on real insular communities suggest that some have reached the endangered state predicted by this model.     

Preference for void-to-solid ratio in residential facades

This paper proposes that there is a need to quantify the value of void-to-solid ratio in residential facades. When quantified, void-to-solid ratio is expected to influence preference for these facades. To test this hypothesis, computer-simulated facades were created using a number of mesh editing and photo-editing software packages. The independent variable, void-to-solid ratio, was varied at three levels of windows' orientations and four levels of buildings' heights, resulting in 60 stimuli. A total of 174 participants were randomly sampled from Mutah University, Jordan, who input a total of 10,440 preference responses to the stimuli. The simulated facades were able to convey the values of void-to-solid ratios to participants. Responses revealed that there is an inverted U-shape relationship between preference for residential facades and their void-to-solid ratio, and that the most preferred range of void-to-solid ratios was (0.4–0.5).     

Computer Inference Of Network Of Ecological Interactions From Sampling Data

Both direct and indirect ecological interactions may occur in an ecosystem with large numbers of taxa. Traditional food web technique is a popular tool to measure the quality and health of the environment. Much of works must be done before constructing a food web for an ecosystem especially with many taxa. This food web is generally specific for some ecological interactions and fixed for a set of given species. It is therefore not an effective method for dynamic and prompt assessment of environment. Ecological interactions and their interactive intensity may be detected by sampling biological taxa in the field and by detecting various between-taxa distances or similarities. Network may clearly exhibit the complex interactions among biological taxa. Statistic tests on various distance or similarity measures and computer designs are required to infer the {network. We develop an algorithm and software to infer the network of direct or indirect ecological interactions in ecosystem. It is a prompt and effective tool in monitoring and assessment of the environment. A redundant network may be inferred and drawn by computer based on the statistic tests on sampling data or the pathway information given in HTML file. Dominant taxa may be found in the network. In total of 16 distance and similarity measures, including Euclidean distance, Manhattan distance, Pearson correlation, partial correlation, point correlation, linkage coefficients, Jaccard coefficient etc., are provided to detect taxa pairs with significant parametric or nonparametric similarities, based on randomization tests and ordinary statistic tests. Criteria to use distance and similarity measures are discussed.     

周边式二次沉淀池流态的计算模拟研究的数值方法

利用一种半解析半离散的数值方法来求解偏微分方程,从而确定二次沉淀池的流态。该方法具有精度高、速度快、占用计算机内存小的特点。所编制软件可在486微机上运行。计算结果与文献相比较,一致性很好,从而验证了本文方法的正确性。还给出了池型尺寸变化对池中心上部水流死区的影响,为具体设计者提供了参考依据。为进一步的优化设计创造了条件。      

Use of computer models of flood inundation to facilitate communication in flood risk management

It is now widely recognised that good communication between multi-disciplinary stakeholders is central to effective flood risk management. Recent developments in Geographical Information Systems, increased availability of accurate digital terrain models from remotely sensed data sources and improved graphical computer interfaces have made the outputs from computer models of flood inundation easily accessible to the stakeholder community. As a consequence, predictions from such models are now being used routinely as a means of communication between engineers and other stakeholders in flood risk management. This paper provides a review of the modelling methods most appropriate for flood risk communication. These are one-dimensional models which are suitable for simulating flood risk at a catchment or sub-catchment scale and appropriate for communicating the impact of strategic flood management decisions and two-dimensional models which can be applied across a range of scales but, are now being regularly applied at the relatively small scale, less than 10 km², where they have the potential to inform and communicate disaster management decisions. The role of such models in communicating between modellers and non-modellers by providing a means for immediate visualisation of “the future” is discussed and illustrated by application to two case studies.     

基于疏散模拟评估超高层建筑疏散系统安全可靠性的研究

利用计算机疏散模拟的手段,根据超高层建筑内基于国标GB50016-2014《建筑设计防火规范》要求设计的安全疏散系统,设计了合理的疏散场景,对超高层建筑内以防烟楼梯为主的安全疏散系统,进行了安全可靠性的技术分析,并针对国内消防业界对超高层建筑内增加一部疏散楼梯的强化措施的安全效益提出了探讨。