An inventory of Lattice Boltzmann models of multiphase flows

This document reports investigations of models of multiphase flows using Lattice Boltzmann methods. The emphasis is on deriving by Chapman-Enskog techniques the corresponding macroscopic equations. The singular interface (Young-Laplace-Gauss) model is described briefly, with a discussion of its limitations. The diffuse interface theory is discussed in more detail, and shown to lead to the singular interface model in the proper asymptotic limit. The Lattice Boltzmann method is presented in its simplest form appropriate for an ideal gas. Four different Lattice Boltzmann models for non-ideal (multi-phase) isothermal flows are then presented in detail, and the resulting macroscopic equations derived. Partly in contradiction with the published literature, it is found that only one of the models gives physically fully acceptable equations. The form of the equation of state for a multiphase system in the density interval above the coexistance line determines surface tension and interface thickness in the diffuse interface theory. The use of this relation for optimizing a numerical model is discussed. The extension of Lattice Boltzmann methods to the non-isothermal situation is discussed summarily.Comment: 59 pages, 5 figure

On the Information Rates of the Plenoptic Function

The {\it plenoptic function} (Adelson and Bergen, 91) describes the visual information available to an observer at any point in space and time. Samples of the plenoptic function (POF) are seen in video and in general visual content, and represent large amounts of information. In this paper we propose a stochastic model to study the compression limits of the plenoptic function. In the proposed framework, we isolate the two fundamental sources of information in the POF: the one representing the camera motion and the other representing the information complexity of the "reality" being acquired and transmitted. The sources of information are combined, generating a stochastic process that we study in detail. We first propose a model for ensembles of realities that do not change over time. The proposed model is simple in that it enables us to derive precise coding bounds in the information-theoretic sense that are sharp in a number of cases of practical interest. For this simple case of static realities and camera motion, our results indicate that coding practice is in accordance with optimal coding from an information-theoretic standpoint. The model is further extended to account for visual realities that change over time. We derive bounds on the lossless and lossy information rates for this dynamic reality model, stating conditions under which the bounds are tight. Examples with synthetic sources suggest that in the presence of scene dynamics, simple hybrid coding using motion/displacement estimation with DPCM performs considerably suboptimally relative to the true rate-distortion bound.Comment: submitted to IEEE Transactions in Information Theor

Chronic Forced and Free Exercise on Cocaine Place Conditioning and Glutamatergic Synaptic Plasticity in the VTA

Exercise may be useful in preventing substance use disorders and addiction. It is well known that chronic exercise, both forced and voluntary, decreases addiction vulnerability in rodent models and likely in humans. However, the mechanism by which chronic exercise accomplishes this has not been fully evaluated. Here, a conditioned place preference (CPP) paradigm was used to measure the learning of cocaine-associated environmental cues in two groups of rats following a period of both forced and free running. It is shown that rats subjected to chronic forced running displayed no significant deviation in learning of contextual cues paired with cocaine through CPP. On the other hand, rats subjected to chronic free running displayed a notable decrease in acquisition of cocaine-CPP. To investigate the mechanism by which chronic exercise affects cocaine-CPP, we will conduct future electrophysiological studies in the ventral tegmental area (VTA), an area that has been widely implicated in the natural reward circuitry of the brain. The VTA and its role in addiction has been studied extensively by the Morikawa Lab, with one previous study finding that repeated social defeat stress enhances glutamatergic synaptic plasticity in the VTA and cocaine-CPP. Essentially, we expect to observe a decrease in long-term potentiation (LTP) of NMDA-mediated glutamatergic synaptic plasticity in the VTA and consequently, a decrease in cocaine-CPP following both chronic forced and free exercise. If observed, our findings will suggest that decreased plasticity of glutamatergic transmission may be responsible for decreased addiction vulnerability through chronic exercise.Neuroscienc

THE INTEGRATION OF SUSTAINABLE PROCUREMENT AND MARKETING - A CASE STUDY OF UNILEVER

Today, we are living in an uncertain world with many issues such as deforestation, malnutrition, climate change, natural disaster, pollution, etc. And all of those events are not only having impacts on our lives but on the business activities all over the world. Therefore, the term ― “sustainability” has become more important than ever. As a matter of fact, integrating sustainability into business strategy and core activities of the companies can be considered as a growing trend. The two functions that are affected most by the sustainability are the procurement and marketing. Hence, this thesis aims to investigate about the relationship between procurement and marketing in the new context of sustainability. It also explores the drivers and the barriers between that relationship of marketing and procurement; and ultimately provides a theoretical framework which was built based on previous studies and which can help understanding the relationship between marketing and procurement. The empirical part was based on the case study of Unilever, one of the largest consumer goods companies in world and the pioneer in integrating sustainability to the business. Exploratory literature review was carried out by utilizing multiple sources such as articles, books and web pages. The thesis identifies various drivers and barriers of the relationship between marketing and procurement. The case shows that Unilever is doing quite well and on the track to achieve the integration between marketing and procurement. This is happening gradually at Unilever given its size and scale and few barriers still need to be overcome. This study could be used as exemplary for other companies that want to become sustainable.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Development of polysulfone/polyetherimide blend membrane for removing carbon dioxide from methane

Monitor of high CO2 content natural gas is very important issue. The content of CO2 in the natural gas will cause the lower of calorific value which effects to the value of the oil. In order to remove CO2, membrane is one of the best options in term of economy. However, the membrane has low selectivity and is not able to apply in industry. The development membrane selectivity is necessary. During this project, two materials used are polysulfone and polyetherimide. The main objective for this study is to develop polymeric membrane for removal of high CO2 at the platform. The method used for drying is solvent evaporation. After drying process, the membrane needs to be characterized. The synthesized membranes will be used for the performance test by using pure CO2 and CH4 gases. The outcome of the project is a membrane which has high selectivity to remove CO2