16 resultados para time-scale
em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland
Resumo:
Tämä pro gradu -tutkielma käsitteleekustannusten ja ajan analysointia elintarviketeollisuuden arvoverkostossa. Teoriaosuuden kantavia käsitteitä ovat arvoverkosto, Lean Management -ideologia, Value Stream Mapping ja Supply Chain Time and Cost Mapping. Tutkimus toteutetaan case - tutkimuksena, ja siinä on piirteitä niin kvalitatiivisesta kuin kvantitatiivisesta tutkimusasetelmasta. Teoriaosuuden lähteinä on käytetty tieteellisissä julkaisuissa ilmestyneitä journal -artikkeleita sekä alan kirjallisuutta. Tutkimus liittyy olennaisena osana Elintarviketeollisuuden Uudistuva Liiketoiminta -projektiin ja antaa tätä kautta kontekstin muille tutkimuksille sekä konkreettisenesimerkin kyseisestä arvoverkostosta. Empiirisen osan case-yrityksinä ovat Saarioinen Oy, Tuoretie Oy ja Ruokakesko Oy. Analyysin kohteena onLiha-Saarioisten valmistama karjalanpiirakka-tuoteryhmä. Konkreettisena tutkimustuloksena on karjalanpiirakan prosessikuvaus koko arvoketjun matkalta, kustannuskertymä, aikaperusteinen analyysi ja kustannus-aika-kuvaaja. Lisäksi arvoketjun matkalla tehdyistä haastatteluista on kerätty kehitysehdotuksia sekä samalla etsitty hukkatoimintoja. Tuloksista voi tehdä sen johtopäätöksen, että karjalanpiirakka on tyypillinen elintarvike, jonka kustannuksista suurin osa on raaka-aineita ja tuotannon työtä. Aikaa arvoketjussa kuluu eniten kaupan hyllyllä. Organisaatioidenyhteistyöllä aikaa ja sitä kautta kustannuksia olisi kuitenkin mahdollisuus vielä karsia.
Resumo:
Tutkimus tarkastelee johdon laskentatoimea yritysverkostoissa. Tutkimuksen tavoitteena on lisätä ymmärrystä koskien sitä, millaisia tarpeita verkostoituneilla yrityksillä on johdon laskentatoimen suhteen ja millaiset ovat verkostotasoisten laskentajärjestelmien soveltamismahdollisuudet. Johdon laskentatoimea ja yritysverkostoja on tutkittu erillisinä alueina jo varsin pitkään, mutta verkostoituneen toimintamuodon yleistymisestä huolimatta johdon laskentatoimen tutkimus nimenomaan verkostoympäristössä onvasta alkuvaiheessa. Tämä tutkimus on toteutettu suomalaisissa verkostoituneissa metalliteollisuusyrityksissä. Tutkitut verkostot muodostuvatverkoston ydinyrityksestä ¿ kärkiyrityksestä - ja sen ympärille ryhmittyneistä pienistä toimittajayrityksistä. Tutkimus on toteutettu käyttäen teemahaastatteluja, joita suoritettiin neljässä eri yritysverkostossa. Tutkimusote on luonteeltaan laadullinen ja pääosin kuvaileva. Verkostojen laskentatoimen tutkimuksessa pienten toimittajayritysten näkemykset ja asenteet laskennan kehittämistä kohtaan ovat jääneet taka-alalle. Tämän tutkimuksen keskeisenä näkökulmana on juuri verkostoituneiden pk-yritystentarpeet, asenteet ja mahdollisuudet osallistua laskentatoimen kehitystyöhön. Tutkimuksessa tarkastellaan johdon laskentatoimea yleisellä tasolla, eikä rajauduta yksittäisiin menetelmiin. Tutkimus toi esille joitakin informaatiotarpeita verkostotasolla. Useita jalostusvaiheita eri yrityksissä käsittävässä tuotannossa vaikeutena on tietää tarkalleen missä tilaus etenee ja milloin tilaus saapuu yritykseen jalostettavaksi. Toimittajayritykset kaipaavat myös tarkempaa ja pidemmän ajanjakson kattavaa tietoa verkoston kärkiyrityksen tilauskannasta. Informaatiopuutteet aiheuttavat turhaa työtä ja vaikeuttavat resurssien ohjausta. Tutkituissa verkostoissa suunnittelua avustavalle budjetoinnille olisi tarpeita, mutta yhteistä budjetointia ei ole käytännössä toteutettu. Verkostojen laskentatoimessa kustannusten avoin esittäminen kumppaneille tai yleisemmin avoimuus koskien muitakin toiminnan mittareita on keskeisin tekijä, johon verkoston laskentatoimen toteuttaminen tiivistyy. Tutkituista verkostoista kahdessa avoimuus toteutui koskien kustannuksia, kahdessa muussa verkostossa kärkiyritykset eivät nähneet toimittajien kustannustietoja verkoston kilpailukyvyn kannalta merkittäväksi. Kustannusten avoimen esittämisen taustatekijöinä korostuivat kärkiyrityksen tuki, monimutkaisten konstruktioiden aiheuttamat hinnoitteluongelmat ja kannattavan asiakassuhteen varmistaminen. Verkostolaskennan kehittämisessä kärkiyrityksen rooli korostuu. Jos toimittajayritykset eivät tunnista verkostolaskennan tarjoamia mahdollisuuksia toiminnan yhteisessä kehittämisessä ja ohjaamisessa, on kärkiyrityksen pystyttävä perustelemaan toimittajille uskottavasti mitä hyötyä laskentajärjestelmistä on koko verkostolle ja erityisesti toimittajayrityksille. Tutkittujen yritysten on pystyttävä rutinoimaan nyt yleisellä tasolla toimiva keskustelu järjestelmälliseksi suunnittelu- ja ohjaustyöksi. Hyvät kokemuksetyksinkertaisistakin laskenta- ja seurantajärjestelmistä parantavat mahdollisuuksia soveltaa myös kattavampia ja luottamuksellisempaa tietoa sisältäviä laskentajärjestelmiä.
Resumo:
Context: BL Lacs are the most numerous extragalactic objects which are detected in Very High Energy (VHE) gamma-rays band. They are a subclass of blazars. Large flux variability amplitude, sometimes happens in very short time scale, is a common characteristic of them. Significant optical polarization is another main characteristics of BL Lacs. BL Lacs' spectra have a continuous and featureless Spectral Energy Distribution (SED) which have two peaks. Among 1442 BL Lacs in the Roma-BZB catalogue, only 51 are detected in VHE gamma-rays band. BL Lacs are most numerous (more than 50% of 514 objects) objects among the sources that are detected above 10 GeV by FERMI-LAT. Therefore, many BL Lacs are expected to be discovered in VHE gamma-rays band. However, due to the limitation on current and near future technology of Imaging Air Cherenkov Telescope, astronomers are forced to predict whether an object emits VHE gamma-rays or not. Some VHE gamma-ray prediction methods are already introduced but still are not confirmed. Cross band correlations are the building blocks of introducing VHE gamma-rays prediction method. Aims: We will attempt to investigate cross band correlations between flux energy density, luminosity and spectral index of the sample. Also, we will check whether recently discovered MAGIC J2001+435 is a typical BL Lac. Methods: We select a sample of 42 TeV BL Lacs and collect 20 of their properties within five energy bands from literature and Tuorla blazar monitoring program database. All of the data are synchronized to be comparable to each other. Finally, we choose 55 pair of datasets for cross band correlations finding and investigating whether there is any correlation between each pair. For MAGIC J2001+435 we analyze the publicly available SWIFT-XRT data, and use the still unpublished VHE gamma-rays data from MAGIC collaboration. The results are compared to the other sources of the sample. Results: Low state luminosity of multiple detected VHE gamma-rays is strongly correlated luminosities in all other bands. However, the high state does not show such strong correlations. VHE gamma-rays single detected sources have similar behaviour to the low state of multiple detected ones. Finally, MAGIC J2001+435 is a typical TeV BL Lac. However, for some of the properties this source is located at the edge of the whole sample (e.g. in terms of X-rays flux). Keywords: BL Lac(s), Population study, Correlations finding, Multi wavelengths analysis, VHE gamma-rays, gamma-rays, X-rays, Optical, Radio
Resumo:
An electric system based on renewable energy faces challenges concerning the storage and utilization of energy due to the intermittent and seasonal nature of renewable energy sources. Wind and solar photovoltaic power productions are variable and difficult to predict, and thus electricity storage will be needed in the case of basic power production. Hydrogen’s energetic potential lies in its ability and versatility to store chemical energy, to serve as an energy carrier and as feedstock for various industries. Hydrogen is also used e.g. in the production of biofuels. The amount of energy produced during hydrogen combustion is higher than any other fuel’s on a mass basis with a higher-heating-value of 39.4 kWh/kg. However, even though hydrogen is the most abundant element in the universe, on Earth most hydrogen exists in molecular forms such as water. Therefore, hydrogen must be produced and there are various methods to do so. Today, the majority hydrogen comes from fossil fuels, mainly from steam methane reforming, and only about 4 % of global hydrogen comes from water electrolysis. Combination of electrolytic production of hydrogen from water and supply of renewable energy is attracting more interest due to the sustainability and the increased flexibility of the resulting energy system. The preferred option for intermittent hydrogen storage is pressurization in tanks since at ambient conditions the volumetric energy density of hydrogen is low, and pressurized tanks are efficient and affordable when the cycling rate is high. Pressurized hydrogen enables energy storage in larger capacities compared to battery technologies and additionally the energy can be stored for longer periods of time, on a time scale of months. In this thesis, the thermodynamics and electrochemistry associated with water electrolysis are described. The main water electrolysis technologies are presented with state-of-the-art specifications. Finally, a Power-to-Hydrogen infrastructure design for Lappeenranta University of Technology is presented. Laboratory setup for water electrolysis is specified and factors affecting its commissioning in Finland are presented.
Resumo:
Tropical forests have decreased drastically especially in the Peruvian Amazon. In Peru deforestation is caused especially by migrant people; building of houses and infrastructure, clearing land for agricultural purposes and illegal logging and mining. Deforestation results in hindering ecosystem vitality, boosting climate change and decreasing livelihood possibilities. As a counterpoint to cutting down trees there is reforestation, which refers to re-establishment of forest cover. Deforestation and reforestation can be analysed in the light of Forest Transition theory. According to it, due to economic growth, the amount forest cover first diminishes but then starts to increase as the economy in general strengthens. Thus, the research framework is set to this theory. In this study the focus is on analysing socioeconomically sustainable reforestation possibilities in the community of Tingana, Peru. It is situated in a municipal conservation area around which deforestation has been heavy. Land cover change is analysed from LandsatTM satellite images covering a 15 year time period, 1995–2010, in the surroundings of the study area. Semi-structured interviews have been done with a sample size of 25 people and shed light on the perspectives on forests, reforestation and economical activities. The synthesis created from the two methods gives information about the possibilities to enforce reforestation in Tingana and the phase of forest transition in the area. The results show that forest cover has decreased around the surroundings of Tingana leaving the conservation area isolated from larger forest areas. Knowing that forest cover has also decreased inside the conservation area due to agricultural expansion it is certain that fragmentation harms biodiversity causing changes in local climate, which can have knock-on effects for farming and local livelihoods. Therefore reforestation is welcomed when it ensures both conservation and financial benefits and when carried out on locals’ terms. Regarding conservation and incomes the best option would be to plant native timber species together with fruit production species to create agroforestry systems. Economically the community should aim towards an economy that relies on ecotourism as it already practiced in the area. Reforestation could increase ecotourism, which then could in turn increase reforestation via revenues. Regarding forest transition it is likely that forest re-establishment will occur if reforestation along with ecotourism is implemented on long time scale.
Resumo:
Tämän tutkimustyön kohteena on TietoEnator Oy:n kehittämän Fenix-tietojärjestelmän kapasiteettitarpeen ennustaminen. Työn tavoitteena on tutustua Fenix-järjestelmän eri osa-alueisiin, löytää tapa eritellä ja mallintaa eri osa-alueiden vaikutus järjestelmän kuormitukseen ja selvittää alustavasti mitkä parametrit vaikuttavat kyseisten osa-alueiden luomaan kuormitukseen. Osa tätä työtä on tutkia eri vaihtoehtoja simuloinnille ja selvittää eri vaihtoehtojen soveltuvuus monimutkaisten järjestelmien mallintamiseen. Kerätyn tiedon pohjaltaluodaan järjestelmäntietovaraston kuormitusta kuvaava simulaatiomalli. Hyödyntämällä mallista saatua tietoa ja tuotantojärjestelmästä mitattua tietoa mallia kehitetään vastaamaan yhä lähemmin todellisen järjestelmän toimintaa. Mallista tarkastellaan esimerkiksi simuloitua järjestelmäkuormaa ja jonojen käyttäytymistä. Tuotantojärjestelmästä mitataan eri kuormalähteiden käytösmuutoksia esimerkiksi käyttäjämäärän ja kellonajan suhteessa. Tämän työn tulosten on tarkoitus toimia pohjana myöhemmin tehtävälle jatkotutkimukselle, jossa osa-alueiden parametrisointia tarkennetaan lisää, mallin kykyä kuvata todellista järjestelmää tehostetaanja mallin laajuutta kasvatetaan.
Resumo:
Reaaliaikaisten käyttöjärjestelmien käyttö sulautetuissa järjestelmissä on kasvamassa koko ajan. Sulautettuja tietokoneita käytetään yhä useammassa kohteessa kuten sähkökäyttöjen ohjauksessa. Sähkökäyttöjen ohjaus hoidetaan nykyisin yleensä nopealla digitaalisella signaaliprosessorilla (DSP), jolloin ohjelmointi ja päivittäminen on hidasta ja vaikeaa johtuen käytettävästä matalan tason Assembler-kielestä. Ratkaisuna yleiskäyttöisten prosessorien ja reaaliaikakäyttöjärjestelmien käyttö. Kaupalliset reaaliaikakäyttöjärjestelmät ovat kalliita ja lähdekoodin saaminen omaan käyttöön jopa mahdotonta. Linux on ei-kaupallinen avoimen lähdekoodin käyttöjärjestelmä, joten sen käyttö on ilmaista ja sitä voi muokata vapaasti. Linux:iin on saatavana useita laajennuksia, jotka tekevät siitä reaaliaikaisen käyttöjärjestelmän. Vaihtoehtoina joko kova (hard) tai pehmeä (soft) reaaliaikaisuus. Linux:iin on olemassa valmiita kehitysympäristöjä mutta ne kaipaavat parannusta ennen kuin niitä voidaan käyttää suuressa mittakaavassa teollisuudessa. Reaaliaika Linux ei sovellus nopeisiin ohjauslooppeihin (<100 ms) koska nopeus ei riitä vielä mutta nopeus kasvaa samalla kun prosessorit kehittyvät. Linux soveltuu hyvin rajapinnaksi nopean ohjauksen ja käyttäjän välille ja hitaampaan ohjaukseen.
Resumo:
This work investigates the possible effect of pressure and residence time to the reaction of aluminum hydroxide into aluminum oxide. Various pressurized conditions are used as well as the help of various residence times. The aim is to increase the conversion of the reaction with the use of different pressures and residence times. The tests were performed with a laboratory scale fluidized bed reactor at the Outotec R&D Center in Frankfurt. Additional test work such as particle size analysis and differential thermal analysis were also carried out. Some calcined samples were also characterized with X-ray diffraction at the University of Auckland to obtain a reaction pathway when using pressurized conditions. All of the results are then compared with previous results.
Resumo:
The paper is focused on feasibility study and market review of small scale bioenergy heating plants in the Russian North-West region. The main focus is effective and competitive usage of low-grade wood for heating purposes in the region. As example of economical feasibility estimation it was chosen the project of reconstruction of small scale boiler plant in Leningrad region that Brofta Oy is planning to implement the nearest time. It includes calculation the payback time with and without interest, the estimation of probable investments, the evaluation of possible risks and research on the potential of small scale heating plants projects. Calculations show that the profitability of this kind of projects is high, but payback time is not very short, because of high level of initial investments. Though, the development of small scale bioenergy heating plants in the region is considered to be the best way to solve the problems of heat supply in small settlements using own biomass resources.
Resumo:
The results shown in this thesis are based on selected publications of the 2000s decade. The work was carried out in several national and EC funded public research projects and in close cooperation with industrial partners. The main objective of the thesis was to study and quantify the most important phenomena of circulating fluidized bed combustors by developing and applying proper experimental and modelling methods using laboratory scale equipments. An understanding of the phenomena plays an essential role in the development of combustion and emission performance, and the availability and controls of CFB boilers. Experimental procedures to study fuel combustion behaviour under CFB conditions are presented in the thesis. Steady state and dynamic measurements under well controlled conditions were carried out to produce the data needed for the development of high efficiency, utility scale CFB technology. The importance of combustion control and furnace dynamics is emphasized when CFB boilers are scaled up with a once through steam cycle. Qualitative information on fuel combustion characteristics was obtained directly by comparing flue gas oxygen responses during the impulse change experiments with fuel feed. A one-dimensional, time dependent model was developed to analyse the measurement data Emission formation was studied combined with fuel combustion behaviour. Correlations were developed for NO, N2O, CO and char loading, as a function of temperature and oxygen concentration in the bed area. An online method to characterize char loading under CFB conditions was developed and validated with the pilot scale CFB tests. Finally, a new method to control air and fuel feeds in CFB combustion was introduced. The method is based on models and an analysis of the fluctuation of the flue gas oxygen concentration. The effect of high oxygen concentrations on fuel combustion behaviour was also studied to evaluate the potential of CFB boilers to apply oxygenfiring technology to CCS. In future studies, it will be necessary to go through the whole scale up chain from laboratory phenomena devices through pilot scale test rigs to large scale, commercial boilers in order to validate the applicability and scalability of the, results. This thesis shows the chain between the laboratory scale phenomena test rig (bench scale) and the CFB process test rig (pilot). CFB technology has been scaled up successfully from an industrial scale to a utility scale during the last decade. The work shown in the thesis, for its part, has supported the development by producing new detailed information on combustion under CFB conditions.
Resumo:
Intensive and critical care nursing is a speciality in its own right and with its own nature within the nursing profession. This speciality poses its own demands for nursing competencies. Intensive and critical care nursing is focused on severely ill patients and their significant others. The patients are comprehensively cared for, constantly monitored and their vital functions are sustained artificially. The main goal is to win time to cure the cause of the patient’s situation or illness. The purpose of this empirical study was i) to describe and define competence and competence requirements in intensive and critical care nursing, ii) to develop a basic measurement scale for competence assessment in intensive and critical care nursing for graduating nursing students, and iii) to describe and evaluate graduating nursing students’ basic competence in intensive and critical care nursing by seeking the reference basis of self-evaluated basic competence in intensive and critical care nursing from ICU nurses. However, the main focus of this study was on the outcomes of nursing education in this nursing speciality. The study was carried out in different phases: basic exploration of competence (phase 1 and 2), instrumentation of competence (phase 3) and evaluation of competence (phase 4). Phase 1 (n=130) evaluated graduating nursing students’ basic biological and physiological knowledge and skills for working in intensive and critical care with Basic Knowledge Assessment Tool version 5 (BKAT-5, Toth 2012). Phase 2 focused on defining competence in intensive and critical care nursing with the help of literature review (n=45 empirical studies) as well as competence requirements in intensive and critical care nursing with the help of experts (n=45 experts) in a Delphi study. In phase 3 the scale Intensive and Critical Care Nursing Competence Scale (ICCN-CS) was developed and tested twice (pilot test 1: n=18 students and n=12 nurses; pilot test 2: n=56 students and n=54 nurses). Finally, in phase 4, graduating nursing students’ competence was evaluated with ICCN-CS and BKAT version 7 (Toth 2012). In order to develop a valid assessment scale of competence for graduating nursing students and to evaluate and establish the competence of graduating nursing students, empirical data were retrieved at the same time from both graduating nursing students (n=139) and ICU nurses (n=431). Competence can be divided into clinical and general professional competence. It can be defined as a specific knowledge base, skill base, attitude and value base and experience base of nursing and the personal base of an intensive and critical care nurse. Personal base was excluded in this self-evaluation based scale. The ICCN-CS-1 consists of 144 items (6 sum variables). Finally, it became evident that the experience base of competence is not a suitable sum variable in holistic intensive and critical care competence scale for graduating nursing students because of their minor experience in this special nursing area. ICCN-CS-1 is a reliable and tolerably valid scale for use among graduating nursing students and ICU nurses Among students, basic competence of intensive and critical care nursing was self-rated as good by 69%, as excellent by 25% and as moderate by 6%. However, graduating nursing students’ basic biological and physiological knowledge and skills for working in intensive and critical care were poor. The students rated their clinical and professional competence as good, and their knowledge base and skill base as moderate. They gave slightly higher ratings for their knowledge base than skill base. Differences in basic competence emerged between graduating nursing students and ICU nurses. The students’ self-ratings of both their basic competence and clinical and professional competence were significantly lower than the nurses’ ratings. The students’ self-ratings of their knowledge and skill base were also statistically significantly lower than nurses’ ratings. However, both groups reported the same attitude and value base, which was excellent. The strongest factor explaining students’ conception of their competence was their experience of autonomy in nursing. Conclusions: Competence in intensive and critical care nursing is a multidimensional concept. Basic competence in intensive and critical care nursing can be measured with self-evaluation based scale but alongside should be used an objective evaluation method. Graduating nursing students’ basic competence in intensive and critical care nursing is good but their knowledge and skill base are moderate. Especially the biological and physiological knowledge base is poor. Therefore in future in intensive and critical care nursing education should be focused on both strengthening students’ biological and physiological knowledge base and on strengthening their overall skill base. Practical implications are presented for nursing education, practice and administration. In future, research should focus on education methods and contents, mentoring of clinical practice and orientation programmes as well as further development of the scale.
Resumo:
Currently, a high penetration level of Distributed Generations (DGs) has been observed in the Danish distribution systems, and even more DGs are foreseen to be present in the upcoming years. How to utilize them for maintaining the security of the power supply under the emergency situations, has been of great interest for study. This master project is intended to develop a control architecture for studying purposes of distribution systems with large scale integration of solar power. As part of the EcoGrid EU Smart Grid project, it focuses on the system modelling and simulation of a Danish representative LV network located in Bornholm island. Regarding the control architecture, two types of reactive control techniques are implemented and compare. In addition, a network voltage control based on a tap changer transformer is tested. The optimized results after applying a genetic algorithm to five typical Danish domestic loads are lower power losses and voltage deviation using Q(U) control, specially with large consumptions. Finally, a communication and information exchange system is developed with the objective of regulating the reactive power and thereby, the network voltage remotely and real-time. Validation test of the simulated parameters are performed as well.
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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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The global interest towards renewable energy production such as wind and solar energy is increasing, which in turn calls for new energy storage concepts due to the larger share of intermittent energy production. Power-to-gas solutions can be utilized to convert surplus electricity to chemical energy which can be stored for extended periods of time. The energy storage concept explored in this thesis is an integrated energy storage tank connected to an oxy-fuel combustion plant. Using this approach, flue gases from the plant could be fed directly into the storage tank and later converted into synthetic natural gas by utilizing electrolysis-methanation route. This work utilizes computational fluid dynamics to model the desublimation of carbon dioxide inside a storage tank containing cryogenic liquid, such as liquefied natural gas. Numerical modelling enables the evaluation of the transient flow patterns caused by the desublimation, as well as general fluid behaviour inside the tank. Based on simulations the stability of the cryogenic storage and the magnitude of the key parameters can be evaluated.