An analysis of performance models for free water surface wetlands

Although treatment wetlands are intended to attenuate pollutants, reliably predicting their performance remains a challenge because removal processes are often complex, spatially heterogeneous, and incompletely understood. Although initially popular for characterizing wetland performance, plug flow reactor models are problematic because their parameters exhibit correlation with hydraulic loading. One-dimensional advective-dispersive-reactive models may also be inadequate when longitudinal dispersion is non-Fickian as a result of pronounced transverse gradients in velocity (preferential flow). Models that make use of residence time distributions have shown promise in improving wetland performance characterization, however their applicability may be limited by certain inherent assumptions, e.g. that transverse mixing is nil. A recently-developed bicontinuum (mobile-mobile) model that addresses some of these weaknesses may hold promise for improving wetland performance modeling, however this model has yet to be tested against real-world wetland data. This paper examines the state of the science of free water surface wetland hydrodynamics and transport modeling, discusses the strengths and weaknesses of various steady state models, and compares them to each other in terms of each model’s ability to represent data sets from monitored wetlands.     

Review of Drogues et dependances and Toxicomanies.

Reviews the books, Drogues et dépendances by Jef-Louis Bonnardeaux (1983) and Toxicomanies by Dollard Cormier (1983. The book by Bonnardeaux is clearly written and is accompanied by illustrations. However, one doubts the utility of the representation of many biochemical formulas. One wishes also for a better structuring of the various chapters. The book by Cormier is an excellent complement to the Bonnardeaux book. Drug addiction is presented as a life style expressing a solution to problems of existence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Generic Management – Agile Unternehmensführung in einem dynamischen UmfeldHubert Biedermann1 und Thomas Schneeberger2

For 50 years teaching and research at the Department of Economic and Management Sciences has been dealing with the management of companies and their units based on the economic principle. Since the early 1990s, the aspects of quality and of environment as well as of risk and security have played an increasing role in the orientation of the companies. The focus on production factors has therefore been expanded, and a general model of leadership has been developed, which includes economic, environmental, and social objectives and is able to structure the management with regard to the dynamics and complexity of the business environment. In addition to resource efficiency, competitive aspects are addressed that contribute to long-term growth and meet the expectations of stakeholders. Complemented by a transformation model, the Generic Management Model provides a framework of models, methods, and tools for agile corporate governance mastering complexity.     

Aluminum compounds as additional crosslinkers for air-drying high-solids alkyd paints

Aluminum compounds, especially complexes of alcohols, are known as additional crosslinkers for air-drying alkyd paints. Particularly, the drying behavior of high-solids alkyd systems applied under adverse conditions may be improved distinctly. Besides the ether- and peroxy-crosslinks resulting from oxidative drying, coordinative crosslinking occurs. However, exterior weathering of paint films containing Al-complexes frequently results in severe embrittlement. In order to cope with these problems, drying and aging of alkyds and Al-complexes were investigated. All ligands in the complex appeared to get lost during drying, a probable cause of poor weathering performance. Using specially developed alkyd paints for Al-compounds, possible ways of controlling embrittlement are discussed. P.O. Box 9300, 6800 SB Arnhem, The Netherlands. P.O. Box 3, 2170 BA Sassenheim, The Netherlands.     

Quantitative phase evaluation of converter slags

The slags formed in the LD vessel during the refining process turn out with different chemical compositions, mineralogical structures and physical properties, in dependence on the charging and processing conditions. Electron probe microanalysis (EPMA) combined with a data processing method for mineralogical analysis was used to characterize the mineralogical phases in LD slags and moreover to determine their volume fractions. By this method some correlations between the phase contents and the chemical composition of LD slags were established. The diagrams gained from this work have proven to be a valuable aid for understanding the interrelationships between the chemical composition, the mineralogical structure and some physical properties of LD slags.     

Intermittent Switching Between Potential Flow and Turbulence in Superfluid Helium at mK Temperatures

Superfluid flow around an oscillating microsphere is investigated at temperatures down to 25 mK. Stable laminar flow below a critical velocity and turbulence at large drives are found to be separated below 0.5 K by an intermediate range of driving forces where the flow is unstable, intermittently switching between laminar and turbulent phases. We have recorded time series of this switching phenomenon and have made a statistical analysis of the switching probability. The mean lifetime of the turbulent phases grows with increasing drive and becomes infinite at a critical value. Stability of the laminar phases above the critical velocity is limited by natural background radioactivity or cosmic rays.     

PHYSIOLOGICAL TESTING OF CARBON NANOTUBES: ARE THEY ASBESTOS-LIKE?

To determine whether carbon nanotubes can induce any significant health hazards we applied methods routinely used in the pathophysiological testing of asbestos-induced disease to show that the soot with a high content of CNTs does not induce any abnormalities of pulmonary function or measurable inflammation in guinea pigs treated with carbon nanotubes.     

Amino‐functionalised mesoporous silica microspheres for immobilisation of Candida antarctica lipase B – application towards greener production of 2,5‐furandicarboxylic acid

In the present study, amino‐functionalised mesoporous silica microspheres were utilised as support for the covalent immobilisation of Candida antarctica lipase B (CaLB) for the subsequent production of 2,5‐furandicarboxylic acid (FDCA) from 2,5‐diformylfuran (DFF). Under the optimised operating conditions of pH 6.5, particle/enzyme ratio of 1.25:1.0 and glutaraldehyde concentration of 4 mM, a maximum CaLB immobilisation yield of 82.4% on silica microspheres was obtained in 12.25 h. The immobilised CaLB was used for the synthesis of alkyl esters, which were utilised along with hydrogen peroxide for FDCA synthesis. The biocatalytic conversion of 30 mM DFF dictated a 77–79% FDCA in 48 h at 30°C; where the turnover number and turnover frequency of immobilised CaLB were 6220.73 mol mol⁻¹ and 129.59 h⁻¹, respectively, for ethyl acetate, against 6297.65 mol mol⁻¹ and 131.2 h⁻¹, respectively, for ethyl butyrate. Upon examining the operational stability, the immobilised CaLB exhibited high stability till five cycles of FDCA production.Inspec keywords: mesoporous materials, organic compounds, biotechnology, silicon compounds, renewable materials, catalysis, catalysts, enzymes, thermal stability, biofuelOther keywords: FDCA production, amino‐functionalised mesoporous silica microspheres, greener production, 2,5‐furandicarboxylic acid, covalent immobilisation, 2,5‐diformylfuran, CaLB immobilisation, Candida antarctica lipase B immobilisation, ethyl butyrate, time 48.0 hour, temperature 30.0 degC, time 12.25 hour