Literature survey

About: Literature survey is a research topic. Over the lifetime, 15372 publications have been published within this topic receiving 459196 citations.

Achieving the promise of transdisciplinarity: a critical exploration of the relationship between transdisciplinary research and societal problem solving

Abstract: Transdisciplinarity is often presented as a way to effectively use scientific research to contribute to societal problem solving for sustainability The aim of this paper is to critically explore this statement This is done in two ways First, a literature survey of transdisciplinary research is used to identify the assumptions that underlie the positive relationship between transdisciplinarity and societal problem solving for sustainability This mapping identifies the claim that in-depth participation of users and the integration of relevant knowledge from both practice and research in real-world problem contexts produce socially robust results that contribute to sustainability Second, the ability to live up to this claim is presented and discussed in five case study projects from Mistra Urban Futures, a transdisciplinary center in Goteborg, Sweden The conclusions show that transdisciplinary processes, which fulfill the above conditions, do produce different types of socially robust knowledge, but this does not necessarily result in the ability to influence change in a sustainable direction This instead creates a paradox in that the participation of stakeholders and the integration of knowledge from diverse sources require spaces that are both embedded in and insulated from practice and science proper Such spaces produce results that are not easily aligned with sector-based target groups and formal policy processes Institutionalizing transdisciplinarity in a boundary organization therefore solves some problems regarding participation and balanced problem ownership However, it also creates new, hybrid problems, regarding knowledge transfer and scalability, which bridge the boundaries and challenge the praxis of planning and policy making

The Dynamics of Fine Powders

Abstract: 1 General Introduction.- 1.1 Powders: what are they?.- 1.2 Powder behavior.- 1.3 Powders in industry.- 1.4 Powder operations.- 1.5 Origin and production of powders.- 1.6 About this book.- 2 Particle and Powder Characteristics.- 2.1 Characterization of single particles.- 2.2 Particle size distribution.- 2.3 The powder packing.- 2.4 The coordination number.- 3 Mechanics of Powders at Rest.- 3.1 The stress tensor.- 3.2 Two-dimensional system.- 3.3 Stress analysis of three-dimensional systems.- 3.4 The yield locus.- 3.5 The angle of repose.- 3.6 The free arch.- 3.7 Incipient fluidization.- 4 Theoretical Derivation of Interparticle Forces.- 4.1 Introduction.- 4.2 The Hamaker theory.- 4.3 Effect of particle deformation.- 4.4 Effect of gas adsorption.- 4.5 Practical implications.- 4.5.1 Powder cohesion.- 4.5.2 Powder elasticity.- 5 Two-phase Systems. The Equations of Motion.- 5.1 Introduction.- 5.2 Averaging of variables.- 5.3 The mass balances.- 5.4 The momentum balances.- 5.4.1 Momentum balance of the solid phase.- 5.4.2 Momentum balance of the continuous phase.- 5.5 Constitutive equations.- 5.5.1 Re ?c, Rc and Rd.- 5.5.2 Re Fs.- 5.5.3 Re ?.- 5.6 The buoyancy.- 6 Stability and Perturbations.- 6.1 Introduction.- 6.2 Continuity waves.- 6.3 The continuity shock wave.- 6.4 Stability of a homogeneous gas-fluidized bed.- 6.5 Other theories.- 6.6 Channelling.- 7 Experiments with Homogeneous Fluidization.- 7.1 Introduction.- 7.2 Description of apparatus.- 7.3 Experimental procedure.- 7.4 Experimental results.- 7.5 The effect of gravity.- 7.5.1 Description of experiments.- 7.6 Discussion and conclusion.- 8 A Model of Expanded Powders.- 8.1 Introduction.- 8.2 The relation between elasticity and porosity.- 8.3 The coordination number.- 8.4 The relation between cohesion and elasticity.- 9 Rheology of Fluidized Powders.- 9.1 Introduction.- 9.2 Literature survey.- 9.3 Description of the apparatus.- 9.4 Measurements.- 9.5 Conditions for stable powder flow.- 9.6 Evaluation of the measurements.- 9.7 Correlation of the wall velocity.- 9.8 Conclusions.- 10 Fluidization in Practice.- 10.1 Introduction.- 10.2 The freely bubbling bed.- 10.2.1 The collapse experiment.- 10.2.2 The bubble frequency.- 10.3 Single bubbles.- 10.3.1 The rising velocity of a bubble.- 10.3.2 Gas exchange with the dense phase.- 10.4 The bubble-cloud mechanism.- 10.5 General proof of cloud mechanism.- 10.6 Correlation with interparticle forces.- 10.7 Overall circulation.- 10.7.1 The momentum equations.- 10.7.2 Derivation of the circulation pattern.- 10.7.3 Discussion.- 11 Handling of Powders.- 11.1 Introduction.- 11.1.1 Experiments in a sand-glass.- 11.1.2 Experiments in a two-dimensional rotating Drum.- 11.1.3 Criterion for fluid dynamic gas-solid interaction.- 11.1.4 Conclusions.- 11.2 Milling experiments.- 11.2.1 The milling model.- 11.2.2 Milling results.- 11.2.3 Visual observation.- 11.2.4 Scaling-up.- 11.3 Mixing and segregation.- 11.3.1 Experiments.

Riparian plant community responses to increased flooding: a meta-analysis

Abstract: A future higher risk of severe flooding of streams and rivers has been projected to change riparian plant community composition and species richness, but the extent and direction of the expected change remain uncertain. We conducted a meta-analysis to synthesize globally available experimental evidence and assess the effects of increased flooding on (1) riparian adult plant and seedling survival, (2) riparian plant biomass and (3) riparian plant species composition and richness. We evaluated which plant traits are of key importance for the response of riparian plant species to flooding. We identified and analysed 53 papers from ISI Web of Knowledge which presented quantitative experimental results on flooding treatments and corresponding control situations. Our meta-analysis demonstrated how longer duration of flooding, greater depth of flooding and, particularly, their combination reduce seedling survival of most riparian species. Plant height above water level, ability to elongate shoots and plasticity in root porosity were decisive for adult plant survival and growth during longer periods of flooding. Both ‘quiescence’ and ‘escape’ proved to be successful strategies promoting riparian plant survival, which was reflected in the wide variation in survival (full range between 0 and 100%) under fully submerged conditions, while plants that protrude above the water level (>20 cm) almost all survive. Our survey confirmed that the projected increase in the duration and depth of flooding periods is sufficient to result in species shifts. These shifts may lead to increased or decreased riparian species richness depending on the nutrient, climatic and hydrological status of the catchment. Species richness was generally reduced at flooded sites in nutrient-rich catchments and sites that previously experienced relatively stable hydrographs (e.g. rain-fed lowland streams). Species richness usually increased at sites in desert and semi-arid climate regions (e.g. intermittent streams).