Sökning: "internal loading"

Visar resultat 1 - 5 av 101 avhandlingar innehållade orden internal loading.

1. 1. Internal Erosion Phenomena in Embankment Dams : Throughflow and internal erosion mechanisms

   Författare :Farzad Ferdos; Anders Wörman; Bijan Dargahi; Fredrik Johansson; Willi Hager; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Internal erosion modelling in porous material; Constitutive law of erosion for closure of continuum-mechanics-based balance equations for numerical modelling; High Reynolds-number turbulent flow; Flow laws; Coarse rockfill material throughflow; Computational Fluid Dynamics.; Civil and Architectural Engineering; Byggvetenskap;

   Sammanfattning :  In this study, two major internal erosion initiation processes, suffusion and concentrated leak mechanisms, which lead to both defect formation in a dam’s body and its foundation and high throughflow in dams subjected to internal erosion were studied. This understanding has the potential to facilitate numerical modelling and expedite dam safety assessment studies. LÄS MER

3. 2. Organic Phosphorus Compounds in Aquatic Sediments : Analysis, Abundance and Effects

   Författare :Joakim Ahlgren; Emil Rydin; Monica Waldebäck; Lars Tranvik; Karin Markides; Sven Blomqvist; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Environmental chemistry; Organic phosphorus; aquatic sediment; eutrophication; NMR; internal loading; sample preparation; extraction; degradation; Miljökemi; Environmental chemistry; Miljökemi;

   Sammanfattning : Phosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought. LÄS MER

4. 3. Influence of Internal Diffusional Limitations on the Performance of an Immobilized Enzyme in Organic Medium

   Författare :Raúl J Barros; Bioteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Biotechnology; internal diffusional; acetonitrile medium; Immobilized a-chymotrypsin; kinetically controlled peptide synthesis; Bioteknik;

   Sammanfattning : The influence of mass-transfer limitations on the performance of immobilized a-chymotrypsin operating in acetonitrile medium has been investigated. The enzyme was immobilized by deposition on various porous carrier materials such as celite, polyamides of different particle sizes, controlled-pore glasses, polypropylene or polyacrylamides. LÄS MER

5. 4. Draw control strategy for sublevel caving mines : A holistic approach

   Författare :Gurmeet Shekhar; Håkan Schunnesson; Anna Gustafson; Jesper Martinsson; Laeeque Daneshmend; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Draw control strategy; sublevel caving SLC ; loading process; draw point; caving operation; Bayesian statistics; probability models; economic models; Mining and Rock Engineering; Gruv- och berganläggningsteknik;

   Sammanfattning : Sublevel caving is an underground mass mining method used for extracting different types of ores from the earth crust. Mines using sublevel caving (SLC) as the primary mining method are generally highly mechanized with standardized and independent unit operations. LÄS MER

7. 5. Investigation of Suffusion in Glacial Till Dam Cores : Testing methods and critical hydraulic gradients

   Författare :Ingrid Silva; Jan Laue; Peter Viklander; Thomas Pabst; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; internal erosion; suffusion; glacial till; dam cores; dams; experimental investigation; hydraulic gradient; testing methods; cohesionless soils; granular soils; Geoteknik; Soil Mechanics;

   Sammanfattning : Suffusion is an internal erosion mechanism that occurs in embankment dams when fine grained particles in the dam core are washed out by seepage. Initiation of internal erosion depends mainly on three major factors: grain size distribution of the soil, stress conditions and hydraulic gradient; whilst its continuation depends on the properties of the filter. LÄS MER