Protection between strains of Passion fruit woodiness virus in sunnhemp

The main objective of the present study was to evaluate the effect of the sunhemp (Crotalaria juncea) host species on the protective ability of two mild strains of Passion fruit woodiness virus (PWV), named F-101 and F-144, which had failed to protect passion flowers (Passiflora edulis f. flavicarpa) in previous experiments. The nucleotide sequences of the capsid protein (CP) gene and the 3'-non-translated region (3'-NTR) of these mild strains and the severe strain of PWV-SP were compared to confirm their relationship. The results of two protective tests with sunhemp plants in the greenhouse and one test under field conditions showed that all plants infected with either mild strain were protected against infection and/or symptom expression of the severe strain of PWV-SP. Evaluation of the relative concentration of the mild strains in sun hemp leaves showed an apparent uniformity in virus distribution in the leaf tissues, different than that which was previously reported for these mild strains in passion flower leaves. These results agree with previous studies that showed the effect of the concentration of the protective strains and the host species in the protection process.

Engineering of Business Critical Web Applications

Research focus of this thesis is to explore options for building systems for business critical web applications. Business criticality here includes requirements for data protection and system availability. The focus is on open source software. Goals are to identify robust technologies and engineering practices to implement such systems. Research methods include experiments made with sample systems built around chosen software packages that represent certain technologies. The main research focused on finding a good method for database data replication, a key functionality for high-availability, database-driven web applications. Research included also finding engineering best practices from books written by administrators of high traffic web applications. Experiment with database replication showed, that block level synchronous replication offered by DRBD replication software offered considerably more robust data protection and high-availability functionality compared to leading open source database product MySQL, and its built-in asynchronous replication. For master-master database setups, block level replication is more recommended way to build high-availability into the system. Based on thesis research, building high-availability web applications is possible using a combination of open source software and engineering best practices for data protection, availability planning and scaling.

Frequency converter protection against supply network phenomena

This master’s thesis is focused on power supply network disturbances and their effects on the frequency converter – one of the components of modern process crane electrical system. The most critical disturbance types, their causes and the effect they bring to crane electrical system was determined in this work. Variety of protective devices used for mitigation of disturbances is investigated. Device protection solutions for the frequency converter used in crane applications are presented. Analyses of the power supply requirements for frequency converter and various components of crane electrical system were carried out and as a result the crane power supply requirements list that guarantees normal crane operation was built. This list is to be included in crane projects for troubleshooting purposes in order to determine potentially dangerous network.

Estimation of existing cable systems in generator-busbar unit and choice the optimal solution for its modernization

The aim of this master’s thesis is to develop an algorithm to calculate the cable network for heat and power station CHGRES. This algorithm includes important aspect which has an influence on the cable network reliability. Moreover, according to developed algorithm, the optimal solution for modernization cable system from economical and technical point of view was obtained. The conditions of existing cable lines show that replacement is necessary. Otherwise, the fault situation would happen. In this case company would loss not only money but also its prestige. As a solution, XLPE single core cables are more profitable than other types of cable considered in this work. Moreover, it is presented the dependence of value of short circuit current on number of 10/110 kV transformers connected in parallel between main grid and considered 10 kV busbar and how it affects on final decision. Furthermore, the losses of company in power (capacity) market due to fault situation are presented. These losses are commensurable with investment to replace existing cable system.

Analysis and Control of Excitation, Field Weakening and Stability in Direct Torque Controlled Electrically Excited Synchronous Motor Drives

Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor’s electromagnetic state and load. The load angle can be limited indirectly by limiting the torque reference. This method is however parameter sensitive and requires a safety margin between the theoretical torque maximum and the actual torque limit. The DTC modulation principle allows however a direct load angle adjustment without any current control. In this work a direct load angle control method has been developed. The method keeps the drive stabile and allows the maximal utilisation of the drive without a safety margin in the torque limitation.

Formal and informal mechanisms for knowledge protection and sharing

The most important knowledge in firms is mostly tacit and embedded in individuals within the organization. This background knowledge that firms possess is used for creation of new knowledge and innovations. As firms today greatly concentrate on their core competencies, they need external knowledge from various collaboration partners. Thus, collaborative relationship governance, as well as control (use of appropriability mechanisms) over background (the input from each firm in innovative activities) and foreground knowledge (the output of collaboration activities) is needed in order to successfully create and capture value from innovative activities without losing core knowledge and competitiveness. Even though research has concentrated on knowledge protection and knowledge sharing, studies that combine both of these views and examine the effects of sharing and protection on value creation and capture have been rather limited. Studies have mainly focused on the protection of the output of innovation while forgetting the protection of the input of innovation. On the other hand, as the research concentrating on the output of innovation tends to favor formal mechanisms, informal mechanisms have remained more unknown to researchers as well as managers. This research aims to combine the perspectives of knowledge sharing and knowledge protection and their relationship with value creation and value capture. The sharing and protection are viewed from two points of view: the use of appropriability mechanisms, as well as governance of the collaborative relationship. The study consists of two parts. The first part introduces the research topic and discusses the overall results. The second part comprises six complementary research publications. Both qualitative and quantitative research methods are used in the study. In terms of results, the findings enhance understanding of the combined use of formal and informal mechanisms for knowledge protection and sharing. Informal mechanisms appear to be emphasized in the protection of background knowledge, and thus are prerequisites for innovation, whereas formal mechanisms are relied on more for protecting the results of innovative activities. However, the simultaneous use of the formal and informal mechanisms that are relevant to the particular industry and innovation context is recommendedthroughout the collaborative innovation process. Further, the study adds to the current knowledge on HRM as an appropriability mechanism: on the firm level its uses include assessing and hedging against employee-related risks such as knowledge leaking and knowledge leaving. A further contribution is to the research on HRM protection and its interrelations with other appropriability mechanisms, its constituents, and its potential use in the area of knowledge protection.

Feasibility study of the available relay protection solutions for microgrids

Thesis talks about relay protection for microgrids. Microgrid operation sets more challenges than traditional utility grid protection because of lower fault current levels. Solutions for these challenges are discussed in this paper. Thesis also studies available relay protection solutions and figures out how they would fit for microgrid protection.

Automation Concept for Electrically Excited LV Synchronous Motor: Implementation into AC500 Programmable Logic Environment

This bachelor’s thesis is a part of the research project realized in the summer 2011 in Lappeenranta University of Technology. The goal of the project was to develop an automation concept for controlling the electrically excited synchronous motor. Thesis concentrates on the implementation of the automation concept into the ABB’s AC500 programmable logic enviroment. The automation program was developed as a state machine with the ABB’s PS501 Control Builder software. For controlling the automation program is developed a fieldbus control and with CodeSys Visualization Tool a local control with control panel. The fieldbus control is done to correspond the ABB drives communication profile and the local control is implemented with a function block which feeds right control words into the statemachine. A field current control of the synchronous motor is realized as a method presented in doctoral thesis of Olli Pyrhönen (Pyrhönen 1998). The Method combines stator flux and torque based openloop control and power factor based feedback control.

Externally excited synchronous machine: Testing the automation concept

This bachelor’s thesis is a part of the research project realized in the summer 2011 in Lappeenranta University of Technology. The goal of the project was to develop an automation concept for controlling the externally excited synchronous motor. Thesis concentrates on the testing planning and testing the system. Testing plan was made for three sectors: For the PLC program testing, for the communication testing and for the whole system testing. PLC program was tested with white box and destructive methods. Communication testing was done by switching maximum com-munication speed and checked if communication was reliable. Whole system testing included among other things speed and torque controlling. The system was tested with exploratory testing also. This enabled more reliable and broader testing than with systematical testing only.

Automation concept for an electrically excited synchronous motor: Setup and requirements specification

This bachelor’s thesis is a part of the research project realized in the summer 2011 in Lappeenranta University of Technology. The goal of the project was to create an automation concept for controlling an electrically excited synchronous motor. This thesis concentrates on the setup and requirements specification part of the concept. The setup consists of ABB AC500 as the PLC master device, DCS800 as an exciter and ACS800 as a frequency converter. The ACS800 frequency converter uses permanent magnet synchronous machine software to control the stator’s magnetic field, the DC drive handles the excitation and the AC500 PLC master controls the communication and functionality of the system. The requirements specification briefly explains the general over-view of the concept, the use and functionality of the PLC program and the requirements needed for the whole concept and the PLC program to work as intended.

Design and Control of Permanent Magnet Synchronous Machine for Hybrid Electric Vehicle

This master’s thesis mainly focuses on the design requirements of an Electric drive for Hybrid car application and its control strategy to achieve a wide speed range. It also emphasises how the control and performance requirements are transformed into its design variables. A parallel hybrid topology is considered where an IC engine and an electric drive share a common crank shaft. A permanent magnet synchronous machine (PMSM) is used as an electric drive machine. Performance requirements are converted into Machine design variables using the vector model of PMSM. Main dimensions of the machine are arrived using analytical approach and Finite Element Analysis (FEA) is used to verify the design and performance. Vector control algorithm was used to control the machine. The control algorithm was tested in a low power PMSM using an embedded controller. A prototype of 10 kW PMSM was built according to the design values. The prototype was tested in the laboratory using a high power converter. Tests were carried out to verify different operating modes. The results were in agreement with the calculations.

Suurnopeus-turbokoneroottoreiden termodynaaminen ja mekaaninen mallinnus sekä rakenneanalyysi

Tässä väitöskirjassa tarkastellaan suurnopeustekniikan eri sovelluksissa ilmeneviä roottoreihin liittyviä rakenteellisia vaatimuksia ja haasteita. Tässä yhteydessä suurnopeustekniikalla tarkoitetaan järjestelyä, jossa sähkökone (moottori, generaattori) ja toimilaite (turbiini, kompressori, puhallin) on kytketty ilman vaihdetta suoraan mekaanisesti yhteen ja jossa yhteisen roottorin pyörimisnopeus on selvästi suurempi kuin 50/60 hertsin verkosta syötetyn kaksinapaisen vaihtovirtasähkökoneen tahtinopeus. Tyypillistä suurnopeuskoneen roottorille on suuri tehotiheys ja suuri mekaaninen kuormitus. Siksi esimerkiksi sähkökoneen jäähdytys on entistä haasteellisempaa kasvavien rautahäviöiden ja pienempien lämmönsiirtopinta-alojen vuoksi. Tämän työn tavoitteet voidaan jakaa kolmeen osaan:  Yhdistetyn sähkö- ja turbokoneen roottorin mekaanisen rakenteen tarkastelu, jonka tavoitteena on pienentää lämmönkehitystä ja tehostaa kriittisten kohtien jäähdytystä. Tähän liittyy sähkömagneettisten häviöiden keskittäminen jäähdytyksen kannalta edullisiin kohtiin  Yhdistetyn sähkö- ja turbokoneen roottorin mekaanisen rakenteen tarkastelu kriittisten ominaistaajuuksien kannalta  Yhdistetyn sähkö- ja turbokoneen roottorin mekaanisen rakenteen analysointi lujuustekniseltä kannalta. Tähän liittyvät mm. erilaiset ahdistussovitteet ja niiden säilyminen korkeilla pyörimisnopeuksilla sekä niiden roottoria jäykistävä vaikutus ja lämmön johtuminen kyseisissä liitospinnoissa. Tämän työn tieteellinen uutuusarvo on nimenomaan yhdistetyn sähkö- ja turbokoneen roottorin rakenteen analysointi ottamalla samanaikaisesti huomioon kaikki edellä mainitut näkökohdat: jäähtyminen erityisen kuumissa kohdissa, sähköisten häviöiden alentaminen ja niiden jakautuman huomioon ottaminen, roottorin jäykkyyden maksimointi, lujuusrasitusten hallinta ja rakenteen mekaaninen stabiliteetti sekä lämpöteknisten ylimenovastusten tarkastelu.

Design of salient pole PM synchronous machines for a vehicle traction application – Analysis and

This doctoral thesis presents a study on the development of a liquid-cooled frame salient pole permanent-magnet-exited traction machine for a four-wheel-driven electric car. The emphasis of the thesis is put on a radial flux machine design in order to achieve a light-weight machine structure for traction applications. The design features combine electromagnetic and thermal design methods, because traction machine operation does not have a strict operating point. Arbitrary load cycles and the flexible supply require special attention in the design process. It is shown that accurate modelling of the machine magnetic state is essential for high-performance operation. The saturation effect related to the cross-saturation has to be taken carefully into account in order to achieve the desired operation. Two prototype machines have been designed and built for testing: one totally enclosed machine with a special magnet module pole arrangement and another through-ventilated machine with a more traditional embedded magnet structure. Both structures are built with magnetically salient structures in order to increase the torque production capability with the reluctance torque component. Both machine structures show potential for traction usage. However, the traditional embedded magnet design turns out to be mechanically the more secure one of these two machine options.

"Protection des animaux en Finlande"

14 x 23 cm