36 resultados para Circadian cycle

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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Selostus: Tarhattujen sinikettujen vuodenaikainen ja vuorokautinen aktiivisuus

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Static process simulation has traditionally been used to model complex processes for various purposes. However, the use of static processsimulators for the preparation of holistic examinations aiming at improving profit-making capability requires a lot of work because the production of results requires the assessment of the applicability of detailed data which may be irrelevant to the objective. The relevant data for the total assessment gets buried byirrelevant data. Furthermore, the models do not include an examination of the maintenance or risk management, and economic examination is often an extra property added to them which can be performed with a spreadsheet program. A process model applicable to holistic economic examinations has been developed in this work. The model is based on the life cycle profit philosophy developed by Hagberg and Henriksson in 1996. The construction of the model has utilized life cycle assessment and life cycle costing methodologies with a view to developing, above all, a model which would be applicable to the economic examinations of complete wholes and which would require the need for information focusing on aspects essential to the objectives. Life cycle assessment and costing differ from each other in terms of the modeling principles, but the features of bothmethodologies can be used in the development of economic process modeling. Methods applicable to the modeling of complex processes can be examined from the viewpoint of life cycle methodologies, because they involve the collection and management of large corpuses of information and the production of information for the needs of decision-makers as well. The results of the study shows that on the basis of the principles of life cycle modeling, a process model can be created which may be used to produce holistic efficiency examinations on the profit-making capability of the production line, with fewer resources thanwith traditional methods. The calculations of the model are based to the maximum extent on the information system of the factory, which means that the accuracyof the results can be improved by developing information systems so that they can provide the best information for this kind of examinations.

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This work was carried out in the laboratory of Fluid Dynamics, at Lappeenranta University of Technology during the years 1991-1996. The research was a part of larger high speed technology development research. First, there was the idea of making high speed machinery applications with the Brayton cycle. There was a clear need to deepen theknowledge of the cycle itself and to make a new approach in the field of the research. Also, the removal of water from the humid air seemed very interesting. The goal of this work was to study methods of designing high speed machinery to the reversed Brayton cycle, from theoretical principles to practical applications. The reversed Brayton cycle can be employed as an air dryer, a heat pump or a refrigerating machine. In this research the use of humid air as a working fluid has an environmental advantage, as well. A new calculation method for the Braytoncycle is developed. In this method especially the expansion process in the turbine is important because of the condensation of the water vapour in the humid air. This physical phenomena can have significant effects on the level of performance of the application. Also, the influence of calculating the process with actual, achievable process equipment efficiencies is essential for the development of the future machinery. The above theoretical calculations are confirmed with two different laboratory prototypes. The high speed machinery concept allows one to build an application with only one rotating shaft including all the major parts: the high speed motor, the compressor and the turbine wheel. The use of oil free bearings and high rotational speed outlines give several advantages compared to conventional machineries: light weight, compact structure, safe operation andhigher efficiency at a large operational region. There are always problems whentheory is applied to practice. The calibrations of pressure, temperature and humidity probes were made with care but still measurable errors were not negligible. Several different separators were examined and in all cases the content of the separated water was not exact. Due to the compact sizes and structures of the prototypes, the process measurement was slightly difficult. The experimental results agree well with the theoretical calculations. These experiments prove the operation of the process and lay a ground for the further development. The results of this work give very promising possibilities for the design of new, commercially competitive applications that use high speed machinery and the reversed Brayton cycle.

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Työn tarkoituksena oli kerätä käyttövarmuustietoa savukaasulinjasta kahdelta suomalaiselta sellutehtaalta niiden käyttöönotosta aina tähän päivään asti. Käyttövarmuustieto koostuu luotettavuustiedoista sekä kunnossapitotiedoista. Kerätyn tiedon avulla on mahdollista kuvata tarkasti laitoksen käyttövarmuutta seuraavilla tunnusluvuilla: suunnittelemattomien häiriöiden lukumäärä ja korjausajat, laitteiden seisokkiaika, vikojen todennäköisyys ja korjaavan kunnossapidon kustannukset suhteessa savukaasulinjan korjaavan kunnossapidon kokonaiskustannuksiin. Käyttövarmuustiedon keräysmetodi on esitelty. Savukaasulinjan kriittisten laitteiden määrittelyyn käytetty metodi on yhdistelmä kyselytutkimuksesta ja muunnellusta vian vaikutus- ja kriittisyysanalyysistä. Laitteiden valitsemiskriteerit lopulliseen kriittisyysanalyysiin päätettiin käyttövarmuustietojen sekä kyselytutkimuksen perusteella. Kriittisten laitteiden määrittämisen tarkoitus on löytää savukaasulinjasta ne laitteet, joiden odottamaton vikaantuminen aiheuttaa vakavimmat seuraukset savukaasulinjan luotettavuuteen, tuotantoon, turvallisuuteen, päästöihin ja kustannuksiin. Tiedon avulla rajoitetut kunnossapidon resurssit voidaan suunnata oikein. Kriittisten laitteiden määrittämisen tuloksena todetaan, että kolme kriittisintä laitetta savukaasulinjassa ovat molemmille sellutehtaille yhteisesti: savukaasupuhaltimet, laahakuljettimet sekä ketjukuljettimet. Käyttövarmuustieto osoittaa, että laitteiden luotettavuus on tehdaskohtaista, mutta periaatteessa samat päälinjat voidaan nähdä suunnittelemattomien vikojen todennäköisyyttä esittävissä kuvissa. Kustannukset, jotka esitetään laitteen suunnittelemattomien kunnossapitokustannusten suhteena savukaasulinjan kokonaiskustannuksiin, noudattelevat hyvin pitkälle luotettavuuskäyrää, joka on laskettu laitteen seisokkiajan suhteena käyttötunteihin. Käyttövarmuustiedon keräys yhdistettynä kriittisten laitteiden määrittämiseen mahdollistavat ennakoivan kunnossapidon oikean kohdistamisen ja ajoittamisen laitteiston elinaikana siten, että luotettavuus- ja kustannustehokkuusvaatimukset saavutetaan.

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The objective of the thesis was to create a framework that can be used to define a manufacturing strategy taking advantage of the product life cycle method, which enables PQP enhancements. The starting point was to study synkron implementation of cost leadership and differentiation strategies in different stages of the life cycles. It was soon observed that Porter’s strategies were too generic for the complex and dynamic environment where customer needs deviate market and product specifically. Therefore, the strategy formulation process is based on the Terry Hill’s order-winner and qualifier concepts. The manufacturing strategy formulation is initiated with the definition of order-winning and qualifying criteria. From these criteria there can be shaped product specific proposals for action and production site specific key manufacturing tasks that they need to answer in order to meet customers and markets needs. As a future research it is suggested that the process of capturing order-winners and qualifiers should be developed so that the process would be simple and streamlined at Wallac Oy. In addition, defined strategy process should be integrated to the PerkinElmer’s SGS process. SGS (Strategic Goal Setting) is one of the PerkinElmer’s core management processes. Full Text: Null

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Taloudellisen laskennan yhdistäminen elinkaariarviointiin (LCA) on alkanut kiinnostaa eri teollisuuden aloja maailmanlaajuisesti viime aikoina. Useat LCA-tietokoneohjelmat sisältävät kustannuslaskentaominaisuuksia ja yksittäiset projektit ovat yhdistäneet ympäristö- ja talouslaskentamenetelmiä. Tässä projektissa tutkitaan näiden yhdistelmien soveltuvuutta suomalaiselle sellu- ja paperiteollisuudelle, sekä kustannuslaskentaominaisuuden lisäämistä KCL:n LCA-ohjelmaan, KCL-ECO 3.0:aan. Kaikki tutkimuksen aikana löytyneet menetelmät, jotka yhdistävät LCA:n ja taloudellista laskentaa, on esitelty tässä työssä. Monet näistä käyttävät elinkaarikustannusarviointia (LCCA). Periaatteessa elinkaari määritellään eri tavalla LCCA:ssa ja LCA:ssa, mikä luo haasteita näiden menetelmien yhdistämiselle. Sopiva elinkaari tulee määritellä laskennan tavoitteiden mukaisesti. Työssä esitellään suositusmenetelmä, joka lähtee suomalaisen sellu- ja paperiteollisuuden erikoispiirteistä. Perusvaatimuksena on yhteensopivuus tavanomaisesti paperin LCA:ssa käytetyn elinkaaren kanssa. Menetelmän yhdistäminen KCL-ECO 3.0:aan on käsitelty yksityiskohtaisesti.

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Energy consumption and energy efficiency have become an issue. Energy consumption is rising all over the world and because of that, and the climate change, energy is becoming more and more expensive. Buildings are major consumers of energy, and inside the buildings the major consumers are heating, ventilation and air-conditioning systems. They usually run at constant speed without efficient control. In most cases HVAC equipment is also oversized. Traditionally heating, ventilation and air-conditioning systems have been sized to meet conditions that rarely occur. The theory part in this thesis represents the basics of life cycle costs and calculations for the whole life cycle of a system. It also represents HVAC systems, equipment, systems controls and ways to save energy in these systems. The empirical part of this thesis represents life cycle cost calculations for HVAC systems. With these calculations it is possible to compute costs for the whole life cycle for the wanted variables. Life cycle costs make it possible to compare which variable causes most of the costs from the whole life point of view. Life cycle costs were studied through two real life cases which were focused on two different kinds of HVAC systems. In both of these cases the renovations were already made, so that the comparison between the old and the new, now existing system would be easier. The study indicates that energy can be saved in HVAC systems by using variable speed drive as a control method.

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The study examines partner selection criteria and the life cycle impacts on them. The target is to define the relevant criteria that should be applied in case of a partnership. In this context partnership means strategic supplier relationship. It is also examined how these criteria change on the different stages of the product and business life cycle. The empirical part is a description of developing Criteria selection tool in the case company. The study is conducted as a qualitative research using constructive and action research methodologies. The Criteria selection tool is a MS Excel workbook, giving the relevant set of supplier criteria depending on the business case. The most essential criteria, the tool will suggest for partner suppliers, are related to strategic fit, development potential and collaborative aspects. On the early stages of the life cycles the criteria related to research and development and growth potential are significant. On the late stages of the life cycles cost reduction potential becomes very important.

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An optimization tool has been developed to help companies to optimize their production cycles and thus improve their overall supply chain management processes. The application combines the functionality that traditional APS (Advanced Planning System) and ARP (Automatic Replenishment Program) systems provide into one optimization run. A qualitative study was organized to investigate opportunities to expand the product’s market base. Twelve personal interviews were conducted and the results were collected in industry specific production planning analyses. Five process industries were analyzed to identify the product’s suitability to each industry sector and the most important product development areas. Based on the research the paper and the plastic film industries remain the most potential industry sectors at this point. To be successful in other industry sectors some product enhancements would be required, including capabilities to optimize multiple sequential and parallel production cycles, handle sequencing of complex finishing operations and to include master planning capabilities to support overall supply chain optimization. In product sales and marketing processes the key to success is to find and reach the people who are involved directly with the problems that the optimization tool can help to solve.

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Direct leaching is an alternative to conventional roast-leach-electrowin (RLE) zinc production method. The basic reaction of direct leach method is the oxidation of sphalerite concentrate in acidic liquid by ferric iron. The reaction mechanism and kinetics, mass transfer and current modifications of zinc concentrate direct leaching process are considered. Particular attention is paid to the oxidation-reduction cycle of iron and its role in direct leaching of zinc concentrate, since it can be one of the limiting factors of the leaching process under certain conditions. The oxidation-reduction cycle of iron was experimentally studied with goal of gaining new knowledge for developing the direct leaching of zinc concentrate. In order to obtain this aim, ferrous iron oxidation experiments were carried out. Affect of such parameters as temperature, pressure, sulfuric acid concentration, ferrous iron and copper concentrations was studied. Based on the experimental results, mathematical model of the ferrous iron oxidation rate was developed. According to results obtained during the study, the reaction rate orders for ferrous iron concentration, oxygen concentration and copper concentration are 0.777, 0.652 and 0.0951 respectively. Values predicted by model were in good concordance with the experimental results. The reliability of estimated parameters was evaluated by MCMC analysis which showed good parameters reliability.

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The structural change of society from product-based business to service- and further to need-based business has caused the fact that work for environmental issues has spread from conventional factories and environmentally harmful production to concern services and offices as well. Almost every company has an office, so a relatively small environmental burden caused by an individual office grows remarkable already at the state level and globally even more. Motivation to work for environmental issues in an individual office could be challenging even without the fact that wasted environmental impacts bound also wasted costs. Besides cost savings, a concretely greener image of a company has its value in the B2Cas well as in the B2B-field. Consumers and clients are more and more conscious of environmental issues and demand concrete actions instead of speeches, good thoughts and meaningless certifications. Internal work for environmental issues at a strategy level is not sufficient, so operational environmental management is needed for changing old practices. This research is about the effects of operative environmental management on the greening process of an office-based business. The research is outlined to concern the operative work in the office including field sales. Target was to concretely lower the environmental impacts of Lyreco Finland and to find cost savings directly by changing the operative practices in the office and also indirectly by affecting the level of environmental knowledge of the personnel. During the greening process, the aim was also to create concrete arguments for marketing as well. The circle of greening process, which was especially created for this diploma work, was used as a method. The circle divides a year to themes and sections separated by factors of environmental impacts. Separation is based on Brett Wills’ thoughts of seven green wastes (Wills, Brett. The Green Intensions. 2009) and follows it uneasily. The circle aimed at ensuring evolutionary growth of knowledge instead of being revolutionary in the changing process. Committing personnel to the process from its start by asking ideas from them and giving them clear directions was an important part of the research of operative management. Because of working from distance, communication with personnel was operated by frequent training days and weekly greening notes via emails and intranet. Also availability for communication was an important task because of the telecommuting. Research results of this work show that operative environmental management in an officebased business today is mostly management of change. When the strategic environmental friendliness is taken into a concrete level, the most important individual factor is motivating the operating personnel. Research shows that evolutionary change is found being an efficient way to make a change. Also understanding one´s own impact on the environmental burden and on the whole greening process clearly motivates the personnel. Results show that in the operative realization of the greening process, clear directions of new working practices, being as concrete as possible, and committing personnel to follow them make the process more effective. The operative environmental management and the cycle of the greening process decrease the environmental burden and save costs. The concrete results could be used as believable arguments in marketing and therefore exploited in communication with interest groups. Commitment of the management is also one of the key factors of success in the greening process. In this research, changes in the business field by a company trade took the focus of the management away from the greening process and made the process more inefficient by decreasing the amount of training days. The circle of greening process will be used as a tool in the future, as well, and therefore it will help observe environmental impacts of a company and increase sustainable development. Commitment of management to the evolutionary environmental work helps the operating personnel lower environmental impacts, decrease costs and build a concretely greener image.