Nuclear diagnostics in the study of relativistic laser-plasma interactions

Laser intensities available for experiments on laser-plasma interactions have increased rapidly during the past decade. Today, intensity in the range 1019-1020 W/cm2 is commonly available. These intensities result in fully relativistic electron motion and effective temperature in the MeV range. It is of great interest to characterise the properties of the fast particles, electrons and ions, emerging from the laser-plasma interaction. However, many of the techniques previously applied when particles energies reached only tens or hundreds of keV have proven insufficient at the highest intensities. In this thesis, nuclear activation techniques have been developed for the study of the fast particles in laser-plasma experiments. These techniques have been applied in experiments carried out at the 50 TW VULCAN laser at Rutherford Appleton Laboratory. Simple nuclear reactions typically have reaction thresholds from a few MeV to tens of MeV. Hence, such reactions have two important properties: they provide energy sensitivity in the presently interesting energy range and they are completely insensitive to particles of low energy, removing the potential ambiguity between detecting many low-energy particles vs. a single energetic one. For the detection of fast electrons, photonuclear reactions have been applied. This is an indirect process where the electrons first generate bremsstrahlung photons which subsequently induce activation in the detector materials. The reaction products are often positron-emitting. This allows sensitive detection of the induced activity by coincidence techniques. In laser-solid experiments, the photonuclear activation has been applied to get information on the angular distribution of the fastest electrons. In plasma accelerator experiments, the technique has been applied for the study of electron angular distribution, temperature and total yield. It has been shown that the electron spectrum is produced by plasma accelerator experiment is nearly an order of magnitude hotter than in laser-solid experiments at similar laser intensity. Fast protons from the laser-solid interactions have been characterised by proton-induced reactions. Such reactions commonly produce positron-emitting products allowing the detection by coindicence techniques. Because of the continuous slowing-down and the short range of protons, spectral measurements could be carried out by using stacked foil detectors. With thin targets, these measurements showed that a much harder proton spectrum is generally observed behind the target than in the plasma blow-off direction. Nuclear reactions induced by heavier ions like 12C in the plasma blow-off were also detected in this work.reviewe

Murskainlaitoksen rungon kehittäminen

Murskainlaitosten runkojen tuotekehitystä ohjaa useasti muuttuneet tarpeet. Muutostarpeita syntyy lainsäädännöstä, asiakastarpeista ja rungon ympärillä muuttuvista rajapinnoista. Tuotekehitystyö tavoittelee muuttuneeseen tarpeeseen vastaamista mahdollisimman tehokkaasti täyttäen tuotekehitysprojektin alussa määritellyt perusedellytykset. Tämä opinnäytetyö tehtiin Metso Minerals Oy:lle, jonka aiheena oli murskainlaitoksen rungon tuotekehitys. Tarkoituksena oli parantaa murskainlaitoksen rungon kuljetettavuutta lavetilla ja vastata näin ollen asiakkaiden tarpeisiin. Lisäksi oli tarve selkeyttää rungon monimutkaisia rakenteita, sillä aikoinaan modulaariseksi suunniteltu runko ei ollut käytössä kuin yhdessä konemallissa. Rungon päivitykselle oli muitakin pienempiä tarpeita, jotka haluttiin toteuttaa isomman runkomuutoksen yhteydessä. Rungon kehityksessä haasteita aiheuttivat muuttuneet teräsrakenteet kriittisissä paikoissa sekä niiden toimivuus. Kuljetettavuuden parantamiseksi päädyttiin korottamaan runkoa ja muotoilemaan runko kuljetuslavetille sopivaksi. Rungon rakenteita onnistuttiin myös yksinkertaistamaan monilta osin heikentämättä kestävyyttä. Työn tuloksista laadittiin valmistuspiirustukset, joiden perusteella runkoa valmistetaan. Runko vaihtui kyseiseen konemalliin osana normaalia tuotejulkaisua. Opinnäytetyön tuloksena syntyneet valmistuspiirustukset ovat luottamuksellisia eikä niitä ole julkaistu opinnäytetyön liitteissä.Product development of a crushing plant’s frames is directed frequently changing needs. The legislation, customer needs and changing interfaces of the frame produces needs of changes. Product development’s target is to reply for changed needs as good as possible and fulfill the basic condition which are determined in the beginning of the product development project. This thesis was commissioned by Metso Minerals Ltd, and deal with the development of a crushing plant’s frame. The purpose was to improve the crusher plant’s frames transportability and respond accordingly to customer needs. There was also a need to clarify the complex structures of the frame because once designed modular frame was used only in one machine model. There was also the need to upgrade the frame as part of the larger frame change. There were several challenges such as steel structures and their functionality. Transportability requires increasing and shapeing the frame to fit the transport carriage. The frame structures were also successfully clarified in many aspects without compromising durability. The results of the work were made in manufacturing drawings which were the base of frame manufacturing. The frame was changed to machine model as part of the normal product release. Manufacturing drawings incurred as a result of the thesis are confidential and has been removed of this thesis

Miesten kansalaistalo Mattilassa tehdään uudenlaista miestyötä

Mattila is a civic house for all men run by Settlement Tampere. In Mattila they do new kind of Men’s Work as a preventive social work. It is based on the theoretical perspectives of Community Social Work, Settlement movement and Freirean Social Pedagogy. The study clarifies the main features of action and practices in the everyday life in Mattila. In order to understand this new kind of Men’s Work we need to see the difference between traditional problem-oriented individual helping work and community based civic work. Man is not a problem and there are no helpers in Mattila. Mattila welcomes all kinds of men and there is no discrimination of color, race, age, sexual orientation or religion. Mattila encourages dialogue between different men with different backgrounds and promotes cultural exchange and awareness of different cultures.Mattila on Setlementti Tampere ry:n Miesten kansalaistalo, jossa tehdään uudenlaista miestyötä ennaltaehkäisevänä kansalaistoimintana. Kirjoituksessa selvitetään Mattilan teoreettisia lähtökohtia eli yhteisösosiaalityötä, freireläistä sosiaalipedagogiikkaa ja uudenlaista miestyötä. Lisäksi selvitetään Mattilan toiminnallisia ratkaisuja ja työskentelyn käytäntöjä Mattilan arjessa. Tarkemmin kuvataan mieslähtöisen kansalaistoiminnan toteuttamista arjessa ja arjen työssä. Uudenlaisessa miestyössä keskeistä on tehdä ero yksilöihin kohdistuvan asiantuntija- ja ongelmakeskeisenauttamistyön sekä miesten tasavertaisuuteen perustuvan yhteisöllisen työn välille. Mattilaan ovat tervetulleita kaikenlaiset miehet ikään, uskontoon, seksuaaliseen suntautumiseen, etniseen taustaan jne. katsomatta. Olennaista on edistää erilaisten miesten välistä dialogia

Neural realignment of spatially separated sound components

Natural auditory scenes often consist of several sound sources overlapping in time, but separated in space. Yet, location is not fully exploited in auditory grouping: spatially separated sounds can get perceptually fused into a single auditory object and this leads to difficulties in the identification and localization of concurrent sounds. Here, the brain mechanisms responsible for grouping across spatial locations were explored in magnetoencephalography (MEG) recordings. The results show that the cortical representation of a vowel spatially separated into two locations reflects the perceived location of the speech sound rather than the physical locations of the individual components. In other words, the auditory scene is neurally rearranged to bring components into spatial alignment when they were deemed to belong to the same object. This renders the original spatial information unavailable at the level of the auditory cortex and may contribute to difficulties in concurrent sound segregation.Peer reviewe