Non-Linear Journal Bearing Model for Analysis of Superharmonic Vibrations of Rotor Systems

A rotating machine usually consists of a rotor and bearings that supports it. The nonidealities in these components may excite vibration of the rotating system. The uncontrolled vibrations may lead to excessive wearing of the components of the rotating machine or reduce the process quality. Vibrations may be harmful even when amplitudes are seemingly low, as is usually the case in superharmonic vibration that takes place below the first critical speed of the rotating machine. Superharmonic vibration is excited when the rotational velocity of the machine is a fraction of the natural frequency of the system. In such a situation, a part of the machine’s rotational energy is transformed into vibration energy. The amount of vibration energy should be minimised in the design of rotating machines. The superharmonic vibration phenomena can be studied by analysing the coupled rotor-bearing system employing a multibody simulation approach. This research is focused on the modelling of hydrodynamic journal bearings and rotorbearing systems supported by journal bearings. In particular, the non-idealities affecting the rotor-bearing system and their effect on the superharmonic vibration of the rotating system are analysed. A comparison of computationally efficient journal bearing models is carried out in order to validate one model for further development. The selected bearing model is improved in order to take the waviness of the shaft journal into account. The improved model is implemented and analyzed in a multibody simulation code. A rotor-bearing system that consists of a flexible tube roll, two journal bearings and a supporting structure is analysed employing the multibody simulation technique. The modelled non-idealities are the shell thickness variation in the tube roll and the waviness of the shaft journal in the bearing assembly. Both modelled non-idealities may cause subharmonic resonance in the system. In multibody simulation, the coupled effect of the non-idealities can be captured in the analysis. Additionally one non-ideality is presented that does not excite the vibrations itself but affects the response of the rotorbearing system, namely the waviness of the bearing bushing which is the non-rotating part of the bearing system. The modelled system is verified with measurements performed on a test rig. In the measurements the waviness of bearing bushing was not measured and therefore it’s affect on the response was not verified. In conclusion, the selected modelling approach is an appropriate method when analysing the response of the rotor-bearing system. When comparing the simulated results to the measured ones, the overall agreement between the results is concluded to be good.

Dimensioning DC-voltage capacitor for a DC-distribution system and dynamic analysis

Technical analysis of Low Voltage Direct Current (LVDC) distribution systems shows that in LVDC transmission the customer voltage quality is higher. One of the problems in LVDC distribution networks that converters both ends of the DC line are required. Because of the converters produce not pure DC voltage, but some fluctuations as well, the huge electrolytic capacitors are required to reduce voltage distortions in the DC-side. This thesis master’s thesis is focused on calculating required DC-link capacitance for LVDC transmission and estimation of the influence of different parameters on the voltage quality. The goal is to investigate the methods of the DC-link capacitance estimation and location in the transmission line.

Structural and operational optimisation : applications in energy systems

In this work mathematical programming models for structural and operational optimisation of energy systems are developed and applied to a selection of energy technology problems. The studied cases are taken from industrial processes and from large regional energy distribution systems. The models are based on Mixed Integer Linear Programming (MILP), Mixed Integer Non-Linear Programming (MINLP) and on a hybrid approach of a combination of Non-Linear Programming (NLP) and Genetic Algorithms (GA). The optimisation of the structure and operation of energy systems in urban regions is treated in the work. Firstly, distributed energy systems (DES) with different energy conversion units and annual variations of consumer heating and electricity demands are considered. Secondly, district cooling systems (DCS) with cooling demands for a large number of consumers are studied, with respect to a long term planning perspective regarding to given predictions of the consumer cooling demand development in a region. The work comprises also the development of applications for heat recovery systems (HRS), where paper machine dryer section HRS is taken as an illustrative example. The heat sources in these systems are moist air streams. Models are developed for different types of equipment price functions. The approach is based on partitioning of the overall temperature range of the system into a number of temperature intervals in order to take into account the strong nonlinearities due to condensation in the heat recovery exchangers. The influence of parameter variations on the solutions of heat recovery systems is analysed firstly by varying cost factors and secondly by varying process parameters. Point-optimal solutions by a fixed parameter approach are compared to robust solutions with given parameter variation ranges. In the work enhanced utilisation of excess heat in heat recovery systems with impingement drying, electricity generation with low grade excess heat and the use of absorption heat transformers to elevate a stream temperature above the excess heat temperature are also studied.

Implementation of an Integrated Activity-Based Costing in a Holistic Database Management System and its Implications for Operations Management

Diplomityössä on tutkittu reaaliaikaisen toimintolaskennan toteuttamista suomalaisen lasersiruja valmistavan PK-yrityksen tietojärjestelmään. Lisäksi on tarkasteltu toimintolaskennan vaikutuksia operatiiviseen toimintaan sekä toimintojen johtamiseen. Työn kirjallisuusosassa on käsitelty kirjallisuuslähteiden perusteella toimintolaskennan teorioita, laskentamenetelmiä sekä teknisessä toteutuksessa käytettyjä teknologioita. Työn toteutusosassa suunniteltiin ja toteutettiin WWW-pohjainen toimintolaskentajärjestelmä case-yrityksen kustannuslaskennan sekä taloushallinnon avuksi. Työkalu integroitiin osaksi yrityksen toiminnanohjaus- sekä valmistuksenohjausjärjestelmää. Perinteisiin toimintolaskentamallien tiedonkeruujärjestelmiin verrattuna case-yrityksessä syötteet toimintolaskentajärjestelmälle tulevat reaaliaikaisesti osana suurempaa tietojärjestelmäintegraatiota.Diplomityö pyrkii luomaan suhteen toimintolaskennan vaatimusten ja tietokantajärjestelmien välille. Toimintolaskentajärjestelmää yritys voi hyödyntää esimerkiksi tuotteiden hinnoittelussa ja kustannuslaskennassa näkemällä tuotteisiin liittyviä kustannuksia eri näkökulmista. Päätelmiä voidaan tehdä tarkkaan kustannusinformaatioon perustuen sekä määrittää järjestelmän tuottaman datan perusteella, onko tietyn projektin, asiakkuuden tai tuotteen kehittäminen taloudellisesti kannattavaa.

1000 V distribution system and its potential in Russia

The application of the three voltage level 20/1/0.4 distribution system in Finland has proved to be an economic solution to enhance the reability of electricity distribution. By using 1 kV voltage level between medium and low voltage networks, the improvement in reability could be reached especially inaerial lines networks. Also considerable savings in investment and outage costscould be archieved compared to the traditional distribution system. This master's thesis is focused on the describing the situation in Russian distribution netwoks and consequent analyses the possibility of applying 1000V distribution system in Russia. The goal is to investigate on the basis of Finnish experience is any possible installation targets in Russia for the new system. Compatibility with Russian safety and quality standards are also studied in this thesis.

Deep-hole drilling process, monitoring system and sensors modifications

 In the drilling processes and especially deep-hole drilling process, the monitoring system and having control on mechanical parameters (e.g. Force, Torque,Vibration and Acoustic emission) are essential. The main focus of this thesis work is to study the characteristics of deep-hole drilling process, and optimize the monitoring system for controlling the process. The vibration is considered as a major defect area of the deep-hole drilling process which often leads to breakage of the drill, therefore by vibration analysis and optimizing the workpiecefixture, this area is studied by finite element method and the suggestions are explained. By study on a present monitoring system, and searching on the new sensor products, the modifications and recommendations are suggested for optimize the present monitoring system for excellent performance in deep-hole drilling process research and measurements.

Dynamic Capabilities and Firm Performance

Firms operating in a changing environment have a need for structures and practices that provide flexibility and enable rapid response to changes. Given the challenges they face in attempts to keep up with market needs, they have to continuously improve their processes and products, and develop new products to match market requirements. Success in changing markets depends on the firm's ability to convert knowledge into innovations, and consequently their internal structures and capabilities have an important role in innovation activities. According 10 the dynamic capability view of the firm, firms thus need dynamic capabilities in (he form ofassets, processes and structures that enable strategic flexibility and support entrepreneurial opportunity sensing and exploitation. Dynamic capabilities are also needed in conditions of rapid change in the operating environment, and in activities such as new product development and expansion to new markets. Despite the growing interest in these issues and the theoretical developments in the field of strategy research, there are still only very few empirical studies, and large-scale empirical studies in particular, that provide evidence that firms'dynamic capabilities are reflected in performance differences. This thesis represents an attempt to advance the research by providing empirical evidence of thelinkages between the firm's dynamic capabilities and performance in intenationalization and innovation activities. The aim is thus to increase knowledge and enhance understanding of the organizational factors that explain interfirm performance differences. The study is in two parts. The first part is the introduction and the second part comprises five research publications covering the theoretical foundations of the dynamic capability view and subsequent empirical analyses. Quantitative research methodology is used throughout. The thesis contributes to the literature in several ways. While a lot of prior research on dynamic capabilities is conceptual in nature, or conducted through case studies, this thesis introduces empirical measures for assessing the different aspects, and uses large-scale sampling to investigate the relationships between them and performance indicators. The dynamic capability view is further developed by integrating theoretical frameworks and research traditions from several disciplines. The results of the study provide support for the basic tenets of the dynamic capability view. The empirical findings demonstrate that the firm's ability to renew its knowledge base and other intangible assets, its proactive, entrepreneurial behavior, and the structures and practices that support operational flexibility arepositively related to performance indicators.

Dynamic Capabilities and Real Options

Tutkielman tavoitteena oli selvittää dynaamisten kyvykkyyksien teorian kehittymistä ja nykytilaa. Työssä tarkastellaan myös mahdollisuuksia yhdistää reaalioptioajattelua ja dynaamisten kyvykkyyksien teoriaa. Tutkielma on toteutettu teoreettisena kirjallisuuskatsauksena. Dynaamisten kyvykkyyksien teorian mukaan muuttuvassa toimintaympäristössä yritysten kilpailuetu perustuu kykyyn rakentaa, yhdistää ja muokata resursseja ja kyvykkyyksiä. Yritysten täytyy pystyä löytämään, sulauttamaan ja muuntamaan tietoa voidakseen tunnistaa uusia mahdollisuuksia ja pystyäkseen reagoimaan niihin. Tutkielma tuo esille uusia yhteyksiä dynaamisten kyvykkyyksien teorian ja yritysten käyttäytymisen välillä. Reaalioptioajattelu auttaa tunnistamaan yrityksen rajojen määrittämiseen vaikuttavia tekijöitä. Työssä tehdään ehdotuksia dynaamisten kyvykkyyksien teorian jatkotutkimusta varten.

Researching Manufacturing Planning and Control system and Master Scheduling in a manufacturing firm.

The objective of this thesis is to research Manufacturing Planning and Control (MPC) system and Master Scheduling (MS) in a manufacturing firm. The study is conducted at Ensto Finland Corporation, which operates on a field of electrical systems and supplies. The paper consists of theoretical and empirical parts. The empirical part is based on weekly operating at Ensto and includes inter-firm material analysis, learning and meetings. Master Scheduling is an important module of an MPC system, since it is beneficial on transforming strategic production plans based on demand forecasting into operational schedules. Furthermore, capacity planning tools can remarkably contribute to production planning: by Rough-Cut Capacity Planning (RCCP) tool, a MS plan can be critically analyzed in terms of available key resources in real manufacturing environment. Currently, there are remarkable inefficiencies when it comes to Ensto’s practices: the system is not able to take into consideration seasonal demand and react on market changes on time; This can cause significant lost sales. However, these inefficiencies could be eliminated through the appropriate utilization of MS and RCCP tools. To utilize MS and RCCP tools in Ensto’s production environment, further testing in real production environment is required. Moreover, data accuracy, appropriate commitment to adapting and learning the new tools, and continuous developing of functions closely related to MS, such as sales forecasting, need to be ensured.

Generation and Characterization of Knockout Mice and Analysis of Patient Material Demonstrates a Role for Tissue Inhibitor of Metalloproteinases 4 (Timp4) in the Cardiovascular System and Tumor Metastasis

This thesis focuses on tissue inhibitor of metalloproteinases 4 (TIMP4) which is the newest member of a small gene and protein family of four closely related endogenous inhibitors of extracellular matrix (ECM) degrading enzymes. Existing data on TIMP4 suggested that it exhibits a more restricted expression pattern than the other TIMPs with high expression levels in heart, brain, ovary and skeletal muscle. These observations and the fact that the ECM is of special importance to provide the cardiovascular system with structural strength combined with elasticity and distensibility, prompted the present molecular biologic investigation on TIMP4. In the first part of the study the murine Timp4 gene was cloned and characterized in detail. The structure of murine Timp4 genomic locus resembles that in other species and of the other Timps. The highest Timp4 expression was detected in heart, ovary and brain. As the expression pattern of Timp4 gives only limited information about its role in physiology and pathology, Timp4 knockout mice were generated next. The analysis of Timp4 knockout mice revealed that Timp4 deficiency has no obvious effect on the development, growth or fertility of mice. Therefore, Timp4 deficient mice were challenged using available cardiovascular models, i.e. experimental cardiac pressure overload and myocardial infarction. In the former model, Timp4 deficiency was found to be compensated by Timp2 overexpression, whereas in the myocardial infarct model, Timp4 deficiency resulted in increased mortality due to increased susceptibility for cardiac rupture. In the wound healing model, Timp4 deficiency was shown to result in transient retardation of re-epithelialization of cutaneous wounds. Melanoma tumor growth was similar in Timp4 deficient and control mice. Despite of this, lung metastasis of melanoma cells was significantly increased in Timp4 null mice. In an attempt to translate the current findings to patient material, TIMP4 expression was studied in human specimens representing different inflammatory cardiovascular pathologies, i.e. giant cell arteritis, atherosclerotic coronary arteries and heart allografts exhibiting signs of chronic rejection. The results showed that cardiovascular expression of TIMP4 is elevated particularly in areas exhibiting inflammation. The results of the present studies suggest that TIMP4 has a special role in the regulation of tissue repair processes in the heart, and also in healing wounds and metastases. Furthermore, evidence is provided suggesting the usefulness of TIMP4 as a novel systemic marker for vascular inflammation.

Implementing an open data system and showing its benefits

Open data refers to publishing data on the web in machine-readable formats for public access. Using open data, innovative applications can be developed to facilitate people‟s lives. In this thesis, based on the open data cases (discussed in the literature review), Open Data Lappeenranta is suggested, which publishes open data related to opening hours of shops and stores in Lappeenranta City. To prove the possibility of creating Open Data Lappeenranta, the implementation of an open data system is presented in this thesis, which publishes specific data related to shops and stores (including their opening hours) on the web in standard format (JSON). The published open data is used to develop web and mobile applications to demonstrate the benefits of open data in practice. Also, the open data system provides manual and automatic interfaces which make it possible for shops and stores to maintain their own data in the system. Finally in this thesis, the completed version of Open Data Lappeenranta is proposed, which publishes open data related to other fields and businesses in Lappeenranta beyond only stores‟ data.

Non-profit maximising organisations and the impact of privatisation, liberalisation, and public-sector reform

I denna avhandling analyserar jag både offentliga och privata företag och organisationer, inklusive universitet, särskilt när det existerar potentiell inre motivation. Jag behandlar både industriell produktion, inklusive infrastruktursektorer med vertikala relationer, och tjänstesektorn. Man tänker sig att ägandet kan påverka kostnadseffektiviteten dels genom olika storlek hos lönetillägg och andra förmåner för de anställda (eng. Internal Rent Capture), och dels via asymmetrisk information. Jag frågar dessutom om det finns andra faktorer än ägande och konkurrens som kan påverka prestandan hos kommersiella företag och ideella organisationer. Dessa frågeställningar aktualiseras av pågående reformer inom den offentliga sektorn, särskilt i samband med den så kallade nya offentliga förvaltningen (eng. New Public Management). Jag analyserar reformernas inverkan på hur bra en organisation fungerar och på den sociala välfärden. Analysen i denna avhandling är teoretisk, men resultaten är relaterade också till den empiriska litteraturen. Avhandlingen är uppdelad i del I och II. I del I sammanfattar jag avhandlingen och sätter den i ett sammanhang, medan del II består av fem redan publicerade essäer. De två första (I–II) är mera traditionella, i och med att de baserar sig på homo economicus (eng. the economic man), utan att beakta den inre motivationen. I essä I (publicerad 2008) bedömer vi fördelar och nackdelar av privatisering och avreglering innanför en sådan ram, men med en betoning också på icke återvinningsbara fasta kostnader och vertikala relationer. I essä II (publicerad 2012) fokuserar vi oss på vertikal separation, och konkurrensutsättning och privatisering i nätverksindustrier. I essäerna III–V vidgas perspektivet genom att införa potentiell inre motivation i en agentmodell. Analysen i essä III (publicerad 2014) tillämpas på offentligt ägande och privatisering. I essäerna IV och V (publicerade 2009 respektive 2013) utvidgas analysen till att även gälla kreativa branscher, särskilt arbete inom universiteten, där den inre motivationen hos de anställda kan tänkas vara avgörande. I dessa essäer tillämpas en analys som inbegriper ett intra-personellt spel inom ramen för en agentmodell med potentiell inre motivation. Vi analyserar sålunda avvägningen mellan ekonomiska incitament och inre motivation.

Work and non-work : on work and meaning

I den politiska retoriken florerar debattinlägg om arbetslivet, och målsättningen är för det mesta att så många som möjligt ska arbeta så länge som möjligt. Att skapa jobb och minimera arbetslösheten ses som de främsta utmaningarna. På ett individuellt plan beskrivs arbete ofta som personligt självförverkligande eller som en nödvändig form av inkomst som kräver att livet struktureras enligt behovet av sysselsättning. I avhandlingen diskuteras hur de här till synes självklara rollerna som arbete spelar kan sägas neutralisera arbete. Med detta menas att kontroverser kring arbetets mening åsidosätts så att politiskt och etiskt grundläggande frågor om ett gott liv och mänskliga gemenskaper inte ges plats. Genom att gå i dialog med kritiska tänkare som Hannah Arendt, André Gorz, Kathi Weeks, Karl Marx och Richard Sennett diskuteras riskerna med att behandla arbete som en resurs, ett gemensamt samhällsprojekt eller individuellt självförverkligande. Vad är nödvändigt arbete? Vad innebär det att arbete är en vara? Vad är problemet med fragmentering av arbete? Det sägs ofta att arbete har blivit alltmer gränslöst – är detta något positivt eller negativt? Utifrån sådana frågor tar avhandlingen fasta på spänningar i arbetets roll i våra liv och i samhället. Genom att artikulera spänningar utmanas en neutralisering av arbetets etiskt och politiskt brännbara dimensioner. Avhandlingen syftar därmed till att lyfta fram ständigt pågående sätt att ifrågasätta och reflektera kring arbetets mening.

Conceptualizing and counteracting the bullying dynamic: Classroom and school contexts matter

Guided by the social-ecological conceptualization of bullying, this thesis examines the implications of classroom and school contexts—that is, students’ shared microsystems—for peer-to-peer bullying and antibullying practices. Included are four original publications, three of which are empirical studies utilizing data from a large Finnish sample of students in the upper grade levels of elementary school. Both self- and peer reports of bullying and victimization are utilized, and the hierarchical nature of the data collected from students nested within school ecologies is accounted for by multilevel modeling techniques. The first objective of the thesis is to simultaneously examine risk factors for victimization at individual, classroom, and school levels (Study I). The second objective is to uncover the individual- and classroom-level working mechanisms of the KiVa antibullying program which has been shown to be effective in reducing bullying problems in Finnish schools (Study II). Thirdly, an overview of the extant literature on classroom- and school-level contributions to bullying and victimization is provided (Study III). Finally, attention is paid to the assessment of victimization and, more specifically, to how the classroom context influences the concordance between self- and peer reports of victimization (Study IV). Findings demonstrate the multiple ways in which contextual factors, and importantly students’ perceptions thereof, contribute to the bullying dynamic and efforts to counteract it. Whereas certain popular beliefs regarding the implications of classroom and school contexts do not receive support, the role of peer contextual factors and the significance of students’ perceptions of teachers’ attitudes toward bullying are highlighted. Directions for future research and school-based antibullying practices are suggested.