Numerical and ExperimentalModelling of Gas Flow and Heat Transfer in the Air Gap of An Electric Machine

This work deals with the cooling of high-speed electric machines, such as motors and generators, through an air gap. It consists of numerical and experimental modelling of gas flow and heat transfer in an annular channel. Velocity and temperature profiles are modelled in the air gap of a high-speed testmachine. Local and mean heat transfer coefficients and total friction coefficients are attained for a smooth rotor-stator combination at a large velocity range. The aim is to solve the heat transfer numerically and experimentally. The FINFLO software, developed at Helsinki University of Technology, has been used in the flow solution, and the commercial IGG and Field view programs for the grid generation and post processing. The annular channel is discretized as a sector mesh. Calculation is performed with constant mass flow rate on six rotational speeds. The effect of turbulence is calculated using three turbulence models. The friction coefficient and velocity factor are attained via total friction power. The first part of experimental section consists of finding the proper sensors and calibrating them in a straight pipe. After preliminary tests, a RdF-sensor is glued on the walls of stator and rotor surfaces. Telemetry is needed to be able to measure the heat transfer coefficients at the rotor. The mean heat transfer coefficients are measured in a test machine on four cooling air mass flow rates at a wide Couette Reynolds number range. The calculated values concerning the friction and heat transfer coefficients are compared with measured and semi-empirical data. Heat is transferred from the hotter stator and rotor surfaces to the coolerair flow in the air gap, not from the rotor to the stator via the air gap, althought the stator temperature is lower than the rotor temperature. The calculatedfriction coefficients fits well with the semi-empirical equations and precedingmeasurements. On constant mass flow rate the rotor heat transfer coefficient attains a saturation point at a higher rotational speed, while the heat transfer coefficient of the stator grows uniformly. The magnitudes of the heat transfer coefficients are almost constant with different turbulence models. The calibrationof sensors in a straight pipe is only an advisory step in the selection process. Telemetry is tested in the pipe conditions and compared to the same measurements with a plain sensor. The magnitudes of the measured data and the data from the semi-empirical equation are higher for the heat transfer coefficients than thenumerical data considered on the velocity range. Friction and heat transfer coefficients are presented in a large velocity range in the report. The goals are reached acceptably using numerical and experimental research. The next challenge is to achieve results for grooved stator-rotor combinations. The work contains also results for an air gap with a grooved stator with 36 slots. The velocity field by the numerical method does not match in every respect the estimated flow mode. The absence of secondary Taylor vortices is evident when using time averagednumerical simulation.

Tietohallinnon portfolion hallinta ammattikorkeakoulussa

Tutkimuksen tarkoituksena on tietohallinnon projektiportfolion hallinnan kehittäminen Metropolia ammattikorkeakoulussa. Portfolion hallinta kattaa projektiesitysten luomisen, projektien ja projektiesitysten arvioinnin ja priorisoinnin sekä projektien käynnistämisen. Painopisteenä arvioinnin ja priorisoinnin lisäksi on portfolion tarkastelu yhtenä kokonaisuutena. Tutkimus toteutettiin konstruktiivisena tutkimuksena, yhteistyössä Metropolia ammattikorkeakoulun kanssa. Tutkimusmenetelminä käytettiin kirjallisuuskatsausta, strukturoituahaastattelua ja kyselylomaketta. Kirjallisuuskatsaus kohdennettiin portfolion hallinnan prosessiin, siinä käytettäviin menetelmiin sekä projektien arviointikriteereihin. Metropoliassa tehtyjen haastattelujen ja kirjallisten kyselyjen avulla selvitettiin portfolion hallinnan nykytilannetta ja kehittämiskohteita. Haastattelemalla kahta julkishallinnon organisaatiota kartoitettiin portfolion hallinnan parhaita käytäntöjä. Tutkimuksen tuloksena on Metropolian tietohallinnon portfolion hallintaprosessi sekä sitä tukevat menetelmät ja projektien arviointikriteerit. Näiden avulla portfolio voidaan priorisoida yhtenäisesti ja systemaattisesti, huomioiden portfolion hallinnan tärkeimmät näkökulmat. Tutkimuksen tulokset ovat hyödynnettävissä Metropolian muissa yksiköissä tai vastaavanlaisissa organisaatioissa

Analysis of corporate social responsibility (CSR) performance and financial performance of selected mining companies

The global concern about sustainability has been growing and the mining industry is questioned about its environmental and social performance. Corporate social responsibility (CSR) is an important issue for the extractive industries. The main objective of this study was to investigate the relationship between CSR performance and financial performance of selected mining companies. The study was conducted by identifying and comparing a selection of available CSR performance indicators with financial performance indicators. Based on the result of the study, the relationship between CSR performance and financial performance is unclear for the selected group of companies. The result is mixed and no industry specific realistic way to measure CSR performance uniformly is available. The result as a whole is contradictory and varies at company level as well as based on the selected indicators. The result of this study confirms that the relationship between CSR performance and financial performance is complicated and difficult to determine. As an outcome, evaluation of benefits of CSR in the mining sector could better be analyzed based on different attributes.

Porin Kuudennen osan tarinoista rakennettu kulttuuriperintö

Tutkimus käsittelee viranomaisten ja asukkaiden välistä vuorovaikutusta kaavaprosessin aikana. Tutkimusalueena on valtakunnallisesti merkittäväksi kulttuuriympäristöksi luokiteltu Porin Kuudes osa, joka on yksi laajimmista yhtenäisenä säilyneistä 1800-luvun lopun puukaupunkialueista Suomessa. Hermeneuttis-fenomenologista otetta soveltava tutkimus perustuu muistitietoaineistoon, joka avaa näkökulman paikallisen kulttuuriperinnön syntymiseen, periytymiseen ja muutokseen. Kuudennen osan vuonna 2012 voimaan tulleessa asemakaavamuutoksessa suojeltiin 405 rakennusta. Sekä viranomaiset että asukkaat haluavat säilyttää arvokkaan ympäristön jälkipolville. Asukkaiden ja viranomaisten lähtökohdat arvottamiselle ovat kuitenkin erilaiset. Asiantuntijoiden näkemys kulttuuriympäristön arvoista perustuu eksplisiittiseen viralliseen tietoon, joka heijastaa positivistista käsitystä maailmasta mitattavista objekteista koostuvana kokonaisuutena. Asukkaiden arvostus asuinaluetta ja sen rakennuksia kohtaan puolestaan nousee sukupolvelta toiselle siirretyn aineettoman perinnön yhteisöllisestä merkityksestä. Heidän kokemuksensa kiteytyy kodin ja kotiseudun käsitteissä ja se tuodaan esiin rakennuksiin liittyvissä tarinoissa. Tulkinta on virallista tietoa haastavaa ja täydentävää. Kestäviä suojelupäätöksiä voidaan tehdä vain viranomaisten ja asukkaiden väliseen tasa-arvoiseen vuoropuheluun perustuen. Tutkimus nostaa asukkaiden kokemuksellisen, paikkaan sitoutuneen hiljaisen tiedon virallisen tiedon rinnalle, kulttuurisesti kestävän maankäytön suunnittelun perustaksi. Koska ihminen toimii sellaisten asioiden puolesta, jotka hän kokee arvokkaaksi, asukaslähtöinen rakennussuojelu on lähtökohtaisesti yhteisön omakseen kokeman aineettoman kulttuuriperinnön suojelua.

Flexible Sensor for Wearable Vital Sign Monitoring System

In modern society, the body health is a very important issue to everyone. With the development of the science and technology, the new and developed body health monitoring device and technology will play the key role in the daily medical activities. This paper focus on making progress in the design of the wearable vital sign system. A vital sign monitoring system has been proposed and designed. The whole detection system is composed of signal collecting subsystem, signal processing subsystem, short-range wireless communication subsystem and user interface subsystem. The signal collecting subsystem is composed of light source and photo diode, after emiting light of two different wavelength, the photo diode collects the light signal reflected by human body tissue. The signal processing subsystem is based on the analog front end AFE4490 and peripheral circuits, the collected analog signal would be filtered and converted into digital signal in this stage. After a series of processing, the signal would be transmitted to the short-range wireless communication subsystem through SPI, this subsystem is mainly based on Bluetooth 4.0 protocol and ultra-low power System on Chip(SoC) nRF51822. Finally, the signal would be transmitted to the user end. After proposing and building the system, this paper focus on the research of the key component in the system, that is, the photo detector. Based on the study of the perovskite materials, a low temperature processed photo detector has been proposed, designed and researched. The device is made up of light absorbing layer, electron transporting and hole blocking layer, hole transporting and electron blocking layer, conductive substrate layer and metal electrode layer. The light absorbing layer is the important part of whole device, and it is fabricated by perovskite materials. After accepting the light, the electron-hole pair would be produced in this layer, and due to the energy level difference, the electron and hole produced would be transmitted to metal electrode and conductive substrate electrode through electron transporting layer and hole transporting layer respectively. In this way the response current would be produced. Based on this structure, the specific fabrication procedure including substrate cleaning; PEDOT:PSS layer preparation; pervoskite layer preparation; PCBM layer preparation; C60, BCP, and Ag electrode layer preparation. After the device fabrication, a series of morphological characterization and performance testing has been done. The testing procedure including film-forming quality inspection, response current and light wavelength analysis, linearity and response time and other optical and electrical properties testing. The testing result shows that the membrane has been fabricated uniformly; the device can produce obvious response current to the incident light with the wavelength from 350nm to 800nm, and the response current could be changed along with the light wavelength. When the light wavelength keeps constant, there exists a good linear relationship between the intensity of the response current and the power of the incident light, based on which the device could be used as the photo detector to collect the light information. During the changing period of the light signal, the response time of the device is several microseconds, which is acceptable working as a photo detector in our system. The testing results show that the device has good electronic and optical properties, and the fabrication procedure is also repeatable, the properties of the devices has good uniformity, which illustrates the fabrication method and procedure could be used to build the photo detector in our wearable system. Based on a series of testing results, the paper has drawn the conclusion that the photo detector fabricated could be integrated on the flexible substrate and is also suitable for the monitoring system proposed, thus made some progress on the research of the wearable monitoring system and device. Finally, some future prospect in system design aspect and device design and fabrication aspect are proposed.