Search results for "Complex."
showing 10 items of 5824 documents
Sorption Equilibria of Ethanol on Cork
2013
International audience; We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of e…
Exploring Environmental and Entrepreneurial Antecedents of Social Performance in Spanish Sports Clubs: A Symmetric and Asymmetric Approach
2020
The social function of non-profit sports clubs is undeniable, so analyzing the factors that influence their performance is vital. The aim of this study is to understand the influence of entrepreneurial factors (entrepreneurial orientation) and environmental factors (dynamism, hostility and complexity) on social performance using a symmetrical (Hierarchical regression model) and asymmetrical (qualitative comparative analysis) approach. The social performance of this particular type of organization is of great importance in an environment where sustainability from a social point of view is increasingly on the agenda of governments, organizations and society in general. A total of 209 Spanish …
Ambidexterity – A New Paradigm for Organizations Facing Complexity
2019
Abstract Complexity is rapidly and inexorably leading the global economy towards new configurations and new dynamics; within this (ever fluid and unstable) framework, the strategic dualities that govern organizations and shape their strategic choices are not only multiplying but also interacting and generating unprecedented challenges: new pairs of (apparent) paradoxes occur, sophisticated interdependencies take place amongst them, and therefore new approaches in search for strategic solutions are imperatively asked. Against this background, the main goal of the paper is to suggest a paradigm of organizational ambidexterity – which gradually integrates various angles and valences into parti…
Changes in fish communities due to benthic habitat shifts under ocean acidification conditions
2020
Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated …
Short-term changes in infiltration between straw mulched and non-mulched soils after wildfire in Mediterranean forest ecosystems
2018
Abstract Water infiltration is a basic parameter to understand the hydrological response of semi-arid or arid soils – where runoff generation is dominated by infiltration-excess – subjected to wildfire. To evaluate the hydrological effects of straw application on a sandy loam soil after wildfire, the unsaturated hydraulic conductivity, water content and temperature of mulched and nonmulched (considered as control) soils were monitored throughout eight months. Compared to untreated soils, straw maintained higher temperatures and water contents in mulched plots, but reduced their unsaturated hydraulic conductivity, particularly in the drier season. These results suggest that straw release may…
A preliminary study on the ecotoxic potency of wastewater treatment plant sludge combining passive sampling and bioassays.
2021
Highlights • The passive samplers collected bioavail able and bioaccessible chemicals from the WWTP sludge samples. • The sampler extracts were acutely and chronically toxic to water flea. • The sampler extracts were cytotoxic and genotoxic. • The sludge treatment such as composting and digesting diminished the toxicity. • Effect-based methods should be part of the risk assessment of sludge recycling. Sewage sludge is an inevitable byproduct produced in wastewater treatment. Reusing nutrient-rich sludge will diminish the amount of waste ending in soil dumping areas and will promote circular economy. However, during sewage treatment process, several potentially harmful organic chemicals are …
Foaming in membrane bioreactors: Identification of the causes
2012
Membrane bioreactors (MBRs) represent by now a well established alternative for wastewater treatment. Their increasing development is undoubtedly related to the several advantages that such technology is able to guarantee. Nevertheless, this technology is not exempt from operational problems; among them the foaming still represents an "open challenge" of the MBR field, due to the high complexity of phenomenon. Unfortunately, very little work has been done on the foaming in MBRs and further studies are required. Actually, there is not a distinct difference between conventional activated system and MBR: the main difference is that the MBR plants can retain most Extracellular Polymeric Substan…
Stabilisation of MSWI bottom ash with sulphide-rich anaerobic effluent.
2007
Effluent of an anaerobic sulphate-reducing wastewater treatment process was used to stabilise bottom ash. The effect of stabilisation on the concentration and binding of Ca, P, S, Cu, Pb, Zn, As, Cr, and Mo were studied by comparing results of sequential extraction from fresh and stabilised bottom ash. The stabilisation treatment improved the retention of Ca, Cu, Pb, S, and Zn in bottom ash compared to a treatment with ion-exchanged water. In addition to retention, Cu, S, and Zn were accumulated from the anaerobic effluent in the bottom ash. Concentrations of As, Cr, and Mo remained on the same level, whereas leaching of P increased compared to control treatment with ion-exchanged water. Im…
A method for measuring low-weight carboxylic acids from biosolid compost
2006
Concentration of low-weight carboxylic acids (LWCA) is one of the important parameters that should be taken into consideration when compost is applied as soil improver for plant cultivation, because high amounts of LWCA can be toxic to plants. The present work describes a method for analysis of LWCA in compost as a useful tool for monitoring compost quality and safety. The method was tested on compost samples of two different ages: 3 (immature) and 6 (mature) months old. Acids from compost samples were extracted at high pH, filtered, and freeze-dried. The dried sodium salts were derivatized with a sulfuric acid–methanol mixture and concentrations of 11 low-weight fatty acids (C1–C10) were a…
High-Performance Liquid Chromatographic Study on Oxidation Products of Lignin and Humic Substances
1991
We describe a convenient method of preparing samples and characterizing the mixture of degradation products obtained from alkaline cupric oxide oxidation of water samples containing lignin and humic substances. The method was applied to one unpolluted humic water sample and a total mill effluent of a kraft pulp mill. The fractions (Mr > 1000) obtained by ultrafi1tration were oxidized and the products (mixtures of degradation products) were analyzed by reversed-phase high-performance liquid chromatography (Spherisorb 5 ODS column). Acetonitrile-0.01 M phosphate buffer (pH 2) was used as the eluent in a gradient system and UV (set at 280 nm) as the detection system. Differences in the …