Boundary Condition Treatment in a Transient Flow Model

Master's thesis in Petroleum engineeringTransient flow modelling used for hydraulic calculations and well control evaluations is a vital part to the safety in the industry to properly prepare and build correct procedures when constructing wells. Modeling liquid and gas flow is complex and it’s important to keep introducing new, efficient ideas to reduce model uncertainties and run time. This can help reduce numerical liabilities, risk and cost. The objective in this thesis has been to implement a new way of treating the boundary conditions in a transient flow model and compare it to more widely used methods. In addition, demanding benchmark cases have been developed to properly test the different boundary condition treatment methods against one another. The AUSMV scheme is used for modeling the flow and pressures in the work in this thesis. The AUSMV scheme uses a simplified transient drift flux model for two-phase flow to predict flow and pressures in the system. Water and air are used instead of oil and gas to reduce the model complexity and instead put focus on the boundary treatment. The model makes a variety of assumptions and include conservation of mass and momentum and is supplied with closure laws. Previous work with AUSMV scheme has mostly used a zero-order extrapolation technique to treat the boundary condition. The first-order extrapolation technique has been introduced recently to improve upon the zero-order. With the work in this thesis, it would be possible to avoid the use of extrapolating the mid-cell value to the boundary completely. The compatibility relations method uses characteristics that transport information from the interior computational domain toward the boundary. On the outgoing boundary, the characteristic compatibility relations together with the imposed physical conditions are used to determine the unknown variables at the boundary points. For a horizontal pipeline with an open end, when considering pressure pulse propagation both the use of compatibility relations method and first-order extrapolation technique worked well. However, the compatibility relations method seems to work slightly better avoiding some unphysical oscillation that was seen initially in the simulation. For a closed well with a migrating kick, the compatibility relations method had no clear benefit over first-order extrapolation technique. The compatibility relations method even had some stability issue for a finer grid. For the open hole cases (case 3 and case 4), a kick is migrating on its own or being circulated out. This leads to an unloading situation where the liquid in front of the kick is forced out of the well violently before the gas breaches through. For the rough grid of 25 cells, there were large differences in results when comparing zero-order and first order extrapolation techniques and compatibility relations method. However, for a fine grid of 100 cells, all models seem to give the same results regarding pressure development. However, there was a difference in maximum liquid and gas flowrates predicted between the boundary condition treatment methods. Compatibility relations method tended to predict a lower maximum liquid flowrate and higher maximum gas flowrate. The input of using a sufficiently refined grid was demonstrated. This reduces numerical diffusion and the difference between the different boundary condition treatment methods are reduced. One can also note that for rough grids, the zero-order extrapolation technique tended to be more unstable. In general, increasing the number of cells in the well will have a greater impact than which boundary condition treatment is chosen. The reason for this is reduced numerical diffusion which is an important factor in simulation results accuracy. In addition, with an increased number of cells, the numerical errors that were introduced with a zero-order extrapolation technique (when considering large gas expansion effect) is reduced. There was a tendency that first-order extrapolation technique in combination with a rough grid produced more numerical problems. There was an issue with extra gas being added in the system for all simulations (except case 1). It was always a similar amount gas being added and it happened early in the simulation. However, this issue is unlikely to have anything to do with the newly implemented boundary condition treatment as it was present whether the compatibility relations method was used or not. There was also a compatibility relations method stability issues for case 2 when using a refined grid. These issues were not solved and needs further investigation

Quantifying separability in limit groups via representations

We show that for any finitely generated subgroup $H$ of a limit group $L$ there exists a finite-index subgroup $K$ containing $H$, such that $K$ is a subgroup of a group obtained from $H$ by a series of extensions of centralizers and free products with $\mathbb Z$. If $H$ is non-abelian, the $K$ is fully residually $H$. We also show that for any finitely generated subgroup of a limit group, there is a finite-dimensional representation of the limit group which separates the subgroup in the induced Zariski topology. As a corollary, we establish a polynomial upper bound on the size of the quotients used to separate a finitely generated subgroup in a limit group. This generalizes the results of Louder, McReynolds and Patel. Another corollary is that a hyperbolic limit group satisfies the Geometric Hanna Neumann conjecture

Relationship between Human Capacity Building and Performance of Micro and Small Enterprises (Mses) In Kisumu City

This paper focused on the relationship between human capacity building and performance of micro and small enterprises (mses) in kisumu city. Despite the central role of mses in employment, industrial transformation and poverty reduction, the competitiveness and growth prospects of Mses Fall below the levels required to meet challenges of increasing and changing basis for competition. Effective management of a company’s human resources is key to business survival in today’s world. Human capacity building can be particularly important for small firms. The need for human capacity building for SMEs in Kenya is of great significance if we are to increase the performance and growth of SMEs and at the same time reduce inefficiency, low productivity and the rate of failures of small firm. A descriptive research design was used to carry out the study. A sample of 320 mses was selected for study using quota and convenience sampling technique. Convenience sampling technique is used to simplify data collection procedures and to avoid the complications of simple random method since the researcher just picks on those who happen to be available and are willing, until the desired size is attained. Both qualitative and quantitative research designs which were descriptive in nature were used; as Gall and Borg noted, “Descriptive studies by nature emphasis interpretation.” The target population of 320 mses was drawn from the 7012 businesses that are licensed by the Municipal Council of Kisumu. The study revealed that appropriate business training was considered a very important contributing factor to growth and Lack of business management training facilities was perceived as a major barrier to growth. One of the reasons for this could be the fact that majority of respondents had not been formally trained in the skills needed to operate an enterprise professionally.The study recommended that if training is to be offered to MSEs, it should encourage as little time away from the workplace as possible and that it should be very flexible and inexpensive

Kustannusjohtaminen kiinteässä yritysverkostossa : Case Helsinki Shipyard Oy

Kustannusjohtamista käsitellään usein yksittäisen yrityksen näkökulmasta, vaikka sitä harjoitetaan myös verkostoissa. Verkostoituminen on jatkuvasti yleistymässä, jonka vuoksi yritysverkostojen hallinnassa on otettava huomioon myös taloudellinen näkökulma. Strategisen kustannusjohtamisen avulla organisaatiot ja verkostot pystyvät havaitsemaan kustannussäästöjä ja samalla parantamaan toiminnan tehokkuutta samalla keskittyen pitkään aikaväliin ja arvoketjun läpi kertyviin kustannuksiin. Vaikka strategisen kustannusjohtamisen rooli liiketoiminnan hallinnassa on tunnistettu, ei strategisen kustannusjohtamisen merkitystä ole täysin omaksuttu telakkateollisuuden kiinteissä verkostoissa. Telakkateollisuudessa verkostot ovat usein kärkiyritysmuotoisia, jolloin yksittäinen yritys, usein telakka, johtaa verkostoa projektiliiketoiminnan muodossa. Strategisen kustannusjohtamisen käyttöä järjestelmänä ei ole tunnistettu toimialalla, vaikka sen menetelmiä käytetään osana telakan verkostojen johtamista. Telakkateollisuuden yritykset toteuttavat merkittävästi resursseja sitovia sekä monimutkaisia projekteja, joiden taloudellinen johtaminen vaatii kärkiyritykseltä tarkkaa seurantaa ja projektinhallintaa. Strategisen kustannusjohtamisen menetelmien hyödyntämisen avulla telakkateollisuuden verkostoissa voidaan parantaa projektin kokonaisvaltaista suoritusta, prosessien tehokkuutta sekä johtaa verkostoa kokonaisvaltaisesti kohti verkoston yhteistä päämäärää eli laivan luovutusta asiakkaalle. Tämän tutkielman tarkoituksena on analysoida kustannusjohtamisen merkitystä kiinteissä yritysverkostoissa. Tutkielmassa käsitellään kustannusjohtamista ja sen menetelmiä osana kiinteän verkoston liiketoiminnan hallintaa. Päätutkimuskysymyksenä on mikä merkitys strategisella kustannusjohtamisella on verkoston liiketoiminnan hallinnassa. Alatutkimuskysymyksinä ovat miten kärkiyritys toteuttaa sisäistä kustannushallintaansa sekä miten verkoston kumppaneiden välillä käytetään kustannusinformaatiota. Tutkielman empiirinen aineisto sisältää puolistrukturoidut teemahaastattelut, jotka on toteutettu case-organisaatiossa Helsinki Shipyard Oy:ssä. Haastatteluihin osallistui 7 henkilöä, jotka toimivat yrityksen johtoportaassa sekä taloushallinnossa, että projektijohdossa. Haastateltavat valikoitiin yhdessä case-organisaation kanssa. Haastateltavilla oli pitkä kokemus telakkateollisuudenalalta. Tämän tutkielman perusteella voidaan todeta telakkateollisuuden verkostojen hyödyntävän strategista kustannusjohtamista osana verkoston liiketoiminnan hallintaa ja sitä kautta voidaan todeta strategisella kustannusjohtamisella olevan merkittävä rooli liiketoiminnan hallinnan kautta. Kustannusjohtamisen menetelmien hyödyntäminen järjestelmänä edesauttaa kärkiyritystä johtamaan verkostoa taloudellisesta näkökulmasta läpi arvoketjun. Vaikka case-organisaatio ei hyödyntänyt avointen kirjojen -mallia osana strategista kustannusjohtamisjärjestelmää, se hyödynsi useita eri strategisen kustannusjohtamisen menetelmiä osana verkoston taloudellista johtamista. Case-yrityksen projektijohtamisen kautta pyrittiin johtamaan verkostoa kokonaisvaltaisesti käyttäen strategisen kustannusjohtamisen menetelmiä osana toiminnan tehostamista

Designing patient registry software for Kenyan healthcare

This thesis will provide an overview on the current patient registries used in Kenyan healthcare systems where the storage of health records electronically has not been utilized. This paper will try to point out some hypothesis and simple prototype on how to design and implement a patient registry software using Microsoft ASP.NET MVC 3 framework. The objective of the thesis is to come up with a well-defined way of transforming the current pa-per based medical records into an electronic medical record that will quicken data collection from multiple centers. Therefore enables clinical officers in tracing their daily activities. The research methodologies applied are: site observation, data from different source or kinds and interviews with the Kenyan healthcare worker at their work place, visiting health institutions to observe how paper based records were kept. Also own experience as a Kenyan was applied. The conclusion realized was that most of the Kenyan healthcare systems are not utilizing the use of electronic medical records as expected. Only a few of the private sectors are using software mainly open source software. The result pointed out that the Kenyan Government should incite the healthcare institutions on the significant of software use. The research was done for a commissioner (Domuset Oy) which is a small scaled healthcare software company. The company is interested in developing healthcare software products in de-veloping country that will be used in monitoring both patients in hospital and at home (home based healthcare)

Determinants of stunting and overweight among young children and adolescents in sub-Saharan Africa

BACKGROUND: Stunting and overweight are nutritional problems affecting most of sub-Saharan Africa. The region now has the world's highest rate of stunting among children (43%), while overweight and obesity are becoming a global epidemic, and Africa is not spared. The past two decades have seen a dramatic increase in obesity in sub-Saharan Africa. OBJECTIVE: The purpose of this systematic review is to explore the determinants of stunting and overweight in sub-Saharan Africa. METHODS: A literature search was conducted in PubMed using the key words stunting, overweight, obesity, Africa, sub-Saharan Africa, determinants, and prevalence. Limits were set to include articles published between 1990 and 2012. The systematic review resulted in 38 studies, and after selection based on title, content, and country of the study, 18 studies were eligible for this review. Data were analyzed by the chi-square test. RESULTS: The prevalence rates of stunting and overweight were dependent on socioeconomic, demographic, and environmental factors. Many studies indicate that male children and those living in a rural setting are more likely to be stunted, whereas overweight among children depends more on age, household composition, occupation of the mother, and the mother's body mass index. Stunting occurred together with overweight among both boys and girls from 1 to 5 years of age. Stunting was more prevalent among boys than among girls. Indicators of socioeconomic status, such as mother's education, mother's occupation, and household income, were some of the determinants directly linked to stunting, whereas environmental factors, such as rural or urban setting and sanitation, influenced both stunting and overweight. Concurrent stunting and overweight is influenced by maternal and household factors, such as maternal height, age, and education, large household size, and lower socioeconomic status. CONCLUSIONS: Although socioeconomic, demographic, and environmental factors were significant in determining stunting and overweight, other factors, such as nutrition and lifestyle, were important risk factors. Stunting in childhood is a risk factor that may result in overweight and obesity later in adolescence and adulthood, indicating the need to screen children below 1 year of age to identify stunting early in life. Promoting exclusive breastfeeding is reported to be important in preventing both stunting and overweight among children. More research is needed to explore the relationship between stunting and overweight and to explore policy guidelines to address the phenomenon

Sidosryhmien vaikutus yrityksen uudelleenbrändäyksen menestyksellisyyteen

Tiivistelmä. Tämä kandidaatintutkielma toteutettiin narratiivisena kirjallisuuskatsauksena ja sen aiheena oli sidosryhmien vaikutus yrityksen uudelleenbrändäyksen menestyksellisyyteen. Tutkielmassa tutkittiin erilaisia mahdollistajia ja estäjiä, jotka vaikuttavat yrityksen uudelleenbrändäyksen menestyksellisyyteen sidosryhmänäkökulmasta sekä sitä, mitkä tekijät aiheuttavat yritykselle uudelleenbrändäystarpeen. Tutkimuksen tarkoituksena oli selvittää lukijalle mitä yrityksen uudelleenbrändäyksellä tarkoitetaan ja miten siitä saadaan mahdollisimman menestyksekäs kohdistaen huomion erityisesti yrityksen sidosryhmiin. Tätä aihetta ei oltu tutkittu sen tarkemmin aikaisemmissa tutkimuksissa, joten tähän tutkielmaan löydettiin näin ollen hyvä näkökulma juuri sidosryhmistä. Tutkielmassa löydettiin viisi erilaista sidosryhmätekijää, jotka vaikuttivat suorasti yrityksen uudelleenbrändäyksen menestyksellisyyteen sekä kolme epäsuorasti vaikuttavaa tekijää. Suorat tekijät olivat vertikaalinen vs. horisontaalinen kommunikointi yrityksen sidosryhmille, sidosryhmien erilaiset intressit, brändin jatkuvuus, sisäiset brändäystoimet sekä asiakkaiden mieltymykset. Epäsuorat tekijät olivat uudelleenbrändäyksen johtaminen, markkinointi sekä tutkiminen. Näitä kaikkia tekijöitä tutkittiin sidosryhmänäkökulmasta niin, että saatiin käsitys siitä, miten yrityksen sidosryhmät ja niiden kohtelu vaikuttaa uudelleenbrändäyksen lopputulemaan. Tutkielmassa myös selvitetään, miten uudelleenbrändäyksen menestystä voidaan mitata vai voidaanko sitä edes mitata. Lukija saa myös tutkielmasta käsityksen mitä perustoimenpiteitä yrityksen uudelleenbrändäykseen tulee aina kuulua. Kokonaisuutena tutkielma perehdyttää lukijan yrityksen uudelleenbrändäyksen ymmärtämiseen sekä sidosryhmätekijöihin, jotka vaikuttavat yrityksen uudelleenbrändäyksen menestyksellisyyteen