Dissertations / Theses on the topic 'SoFi'

Tungmetallflödet i den urbana miljön kan leda till resursproblem för att återföring avavloppsslam som växtnäring till brukbar jord kan försvåras av tungmetallhalter. Syftet med examensarbetet var att bidra till Käppalaförbundets uppströmsarbete genom att identifiera tungmetallkällor i avloppssystemet. Detta uppnås genom en substansflödesanalys med avseende på metallerna kadmium, koppar, krom, kvicksilver och zink för kommunerna Sigtuna och Solna vilka tillhör Käppalaförbundets upptagningsområde. Verktyget som därvidlag utvecklas identifierar tungmetallkällor, storleken av utsläppen och ger information om var åtgärdsinsatser är effektivt.

För verktygsutvecklingen definierades det studerade systemet till fem områden: hushåll, verksamhetsutövare, dagvatten, tillskottsvatten och övrigt. Tungmetallkällor identifierades och grupperades till ett av de fem delområdena. För kvantifiering av flöden från källor sammanställdes en schablonvärdestabell med emissionskoefficienter och formler och antaganden för beräkningar. Fallstudier gjordes för kommunerna Sigtuna och Solna för att testa verktyget och göra en substansflödesanalys för de fem studerade tungmetallerna. En resultatkontroll och en känslighetsanalys gjordes för att skatta rimligheten i resultaten och osäkerheter i verktyget.

Arbetet resulterade i verktyget SoFi (Source Finder), vilket är uppbyggt i Microsoft Office Excel och beräknar tillförda mängder och källfördelning av tungmetaller till avloppssystemet. SoFi kan också beräkna var det är effektivt med åtgärdsinsatser. Resultaten från fallstudierna visade att den största källan med tillförsel av tungmetaller till avloppssystemet från de två kommunerna var hushållen. Resultatkontrollen visade att beräknade mängder generellt överrensstämde bra med uppskattade mängder från respektive område, men att en underskattning av zink erhölls. Känslighetsanalysen visade att verktyget är känsligt för osäkerheter i emissionskoefficienterna. Vid uppströmsarbete kan SoFi bidra med underlag vid åtgärdsplanering. Exempel på åtgärdsinsatser som rekommenderas mot hushållen är informationskampanjer för att medvetandegöra vilka varor som innehåller och emitterar tungmetaller till avloppssystemet. En intressant möjlig vidareutveckling av SoFi är en utvidgning av hushållsdelen till att identifiera vilka varor och produkter därifrån som bidrar mest med tungmetaller för att möjliggöra riktade informationskampanjer.

As more and more constructions are concentrated in densely populated urban areas, there is an increasing need to construct buildings and geotechnical structures on soft clay materials, which usually produce significant creep deformation. Although a lot of research work has been related to the creep behaviour of a natural clay material, there are still many questions about this phenomenon. Even today, prediction of the time dependent deformation is generally very problematic. Detailed laboratory, in-situ and numerical studies of soft soil creep are necessary for the better understanding and consequently, better prognosis of this behaviour. All these studies were performed and will be presented in this thesis.

The long-term, one-dimensional consolidation has been investigated by oedometer tests on undisturbed Norwegian Kvenild quick clay, undisturbed Norwegian Glava clay, undisturbed and remolded Norwegian Onsøy clay and undisturbed Czech Terlicko clayey shale. All tests have been performed in an incremental loading oedometer apparatus with a lever arm, where, in the case of the Glava clay and the Terlicko clayey shale, two sizes of oedometer rings have been used. Detailed means of evaluating the stress-strain-time oedometer behaviour using a time resistance concept introduced by Professor Nilmar Janbu [46,48] is described. The application of the Soft-soil-creep model is presented. This is implemented in the geotechnical finite element program PLAXIS 8.1, for the mathematical modelling of the longterm oedometer test, with emphasis on the correct choice of the input parameters based on the oedometer test results, and their influence to the model’s behaviour.

The undrained and drained deviatoric creep behaviour of the Norwegian Glava clay and the Czech Terlicko clayey shale have been studied under triaxial compression. Two different triaxial apparatuses have been used in the study - standard triaxial apparatus made by Wille Geotechnik Gmbh and unique Creep Triaxial apparatus made at NTNU. A large number of undrained and drained deviatoric creep tests under different conditions have been carried out on 100x50 mm (1:2) and 50x50 mm (1:1) cylindrical specimens. Evaluation of the deviatoric creep behaviour based on the time resistance concept together with detailed description of tests conditions is reported. Data is presented showing the relation between stress level, i.e. degree of shear mobilisation at the start of the creep, time, pore pressure development and accumulated axial creep strain. Significant effort has been put into the study of the undrained triaxial tests on 1:1 clay specimens in general and undrained deviatoric creep triaxial tests on 1:1 clay specimens in particular. The problem connected with the pore pressure development and measurement is presented. A 2D numerical study of the undrained triaxial deviatoric creep tests has been done on 1:1 and 1:2 specimens using the finite element program PLAXIS 8.1. There is also a comparison of the laboratory and numerical behaviour.

Study of the viscosity and creep behaviour of a natural clay has been performed with modular compact rheometer. The MCR 300 rheometer has been used for the rheological investigation of the Norwegian Glava clay. Oscillatory, rotational and creep tests have been done with this apparatus. The basic characterisation of these tests is presented together with their evaluation. Deviatoric creep tests on modular compact rheometer have been evaluated based on the time resistance concept and compared with deviatoric creep tests on a standard triaxial apparatus. The analysis of the Czech Terlicko dam with emphasis on the creep behaviour has been performed based on the cooperation with the Povodi Odry, a.s., Czech Republic. A detailed investigation of the undisturbed clayey shale from the Terlicko dam substratum has been done in the geotechnical and geological laboratory. The characterisation of Terlicko clayey shale is reported base on the laboratory tests results. The in-situ behaviour of the Terlicko dam with emphasis to the uplift of the righthand slope hillside is described. In order to understand the in-situ behaviour a numerical study of the Terlicko dam has been done with PLAXIS 8.1 and Soft-soilcreep model. Results from this 2D numerical test together with recommendations and suggestions are presented.

This document introduces the Soft Shadow Mip-Maps technique, which consists of three methods for overcoming the fundamental limitations of filtering-oriented soft shadows. Filtering-oriented soft shadowing techniques filter shadow maps with varying filter sizes determined by desired penumbra widths. Different varieties of this approach have been commonly applied in interactive and real-time applications. Nonetheless, they share some fundamental limitations. First, soft shadow filter size is not always guaranteed to be the correct size for producing the right penumbra width based on the light source size. Second, filtering with large kernels for soft shadows requires a large number of samples, thereby increasing the cost of filtering. Stochastic approximations for filtering introduce noise and prefiltering leads to inaccuracies. Finally, calculating shadows based on a single blocker estimation can produce significantly inaccurate penumbra widths when the shadow penumbras of different blockers overlap.

We discuss three methods to overcome these limitations. First, we introduce a method for computing the soft shadow filter size for a receiver with a blocker distance. Then, we present a filtering scheme based on shadow mip-maps. Mipmap-based filtering uses shadow mip-maps to efficiently generate soft shadows using a constant size filter kernel for each layer, and linear interpolation between layers. Finally, we introduce an improved blocker estimation approach. With the improved blocker estimating, we explore the shadow contribution of every blocker by calculating the light occluded by potential blockers. Hence, the calculated penumbra areas correspond to the blockers correctly. Finally, we discuss how to select filter kernels for filtering.

These approaches successively solve issues regarding shadow penumbra width calculation apparent in prior techniques. Our result shows that we can produce correct penumbra widths, as evident in our comparisons to ray-traced soft shadows. Nonetheless, the Soft Shadow Mip-Maps technique suffers from light bleeding issues. This is because our method only calculates shadows using the geometry that is available in the shadow depth map. Therefore, the occluded geometry is not taken into consideration, which leads to light bleeding. Another limitation of our method is that using lower resolution shadow mip-map layers limits the resolution of the shadow placement. As a result, when a blocker moves slowly, its shadow follows it with discrete steps, the size of which is determined by the corresponding mip-map layer resolution.

This thesis describes the development of soft x-rayreflective optics, instrumentation and applications for compactsoft x-ray microscopy. The microscope is based on a table-topliquid-jet-target laser-plasma source in combination with aspherical normal-incidence multilayer condenser mirror andnanofabricated diffractive optics for imaging. High-resolutionimaging is performed at the wavelength 3.374 nm in thewater-window (2.3 - 4.4 nm), where natural contrast betweencarbon and oxygen allows imaging of unstained biologicalmaterial in their natural aqueous environment.

The design and implementation of a compact soft x-rayreflectometer based on a laser-plasma source is described. Thereflectometer allows rapid and accurate characterization ofnormal-incidence multilayer coatings used at water-windowwavelengths. This instrument, which measures absolutereflectivity and multilayer period, is now used in thefabrication process, aiming to improve the soft x-raynormal-incidence multilayer condenser system of the compactsoft x-ray microscope. Latest results from the developmentprocess are presented.

A new design of the compact soft x-ray microscope, withimprovements in mechanical and thermal stability, providesuser-friendly and daily operation. This includes also a newnozzle design for the liquid-jet-target laser-plasma source,which enables higher source stability and operation withcryogenic liquids. In addition, a new experimental arrangementunder construction is briefly described. It will utilize acondenser zone plate and operate at the wavelength 2.478nm.

Finally, performance test of the compact soft x-raymicroscope is presented and discussed. In addition, a projectto explore the use of soft x-ray microscopy for imaging sensorycells is described. The high-resolution imaging of these cellswas performed at the synchrotron-based soft x-ray microscope atLawrence Berkeley National Laboratory (LBNL).

To date, most of the research in simulation optimization has been focused on single response optimization on the continuous space of input parameters. However, the optimization of more complex systems does not fit this framework. Decision makers often face the problem of optimizing multiple performance measures of systems with both continuous and discrete input parameters. Previously acquired knowledge of the system by experts is seldomincorporated into the simulation optimization engine. Furthermore, when the goals of the system design are stated in natural language or vague terms, current techniques are unable to deal with this situation. For these reasons, we define and study the fuzzy single response simulation optimization (FSO) and fuzzy multiple response simulation optimization (FMSO) problems.

The primary objective of this research is to develop an efficient and robust method for simulation optimization of complex systems with multiple vague goals. This method uses a fuzzy controller to incorporate existing knowledge to generate high quality approximate Pareto optimal solutions in a minimum number of simulation runs.

For comparison purposes, we also propose an evolutionary method for solving the FMSO problem. Extensive computational experiments on the design of a flow line manufacturing system (in terms of tandem queues with blocking) have been conducted. Both methods are able to generate high quality solutions in terms of Zitzlerand Thiele's "dominated space" metric. Both methods are also able to generate an even sample of the Pareto front. However, the fuzzy controlled method is more efficient, requiring fewer simulation runs than the evolutionary method to achieve the same solution quality.

To accommodate the complexity of natural language, this research also provides a new Bezier curve-based mechanism to elicit knowledge and express complex vague concepts. To date, this is perhaps the most flexible and efficient mechanism for both automatic and interactive generation of membership functions for convex fuzzy sets.