Antiikin pedagoginen perintö

Kirjallisuusarvostelu

Spatial modeling techniques for mapping and characterization of acid sulfate soils

Acid sulfate (a.s.) soils constitute a major environmental issue. Severe ecological damage results from the considerable amounts of acidity and metals leached by these soils in the recipient watercourses. As even small hot spots may affect large areas of coastal waters, mapping represents a fundamental step in the management and mitigation of a.s. soil environmental risks (i.e. to target strategic areas). Traditional mapping in the field is time-consuming and therefore expensive. Additional more cost-effective techniques have, thus, to be developed in order to narrow down and define in detail the areas of interest. The primary aim of this thesis was to assess different spatial modeling techniques for a.s. soil mapping, and the characterization of soil properties relevant for a.s. soil environmental risk management, using all available data: soil and water samples, as well as datalayers (e.g. geological and geophysical). Different spatial modeling techniques were applied at catchment or regional scale. Two artificial neural networks were assessed on the Sirppujoki River catchment (c. 440 km2) located in southwestern Finland, while fuzzy logic was assessed on several areas along the Finnish coast. Quaternary geology, aerogeophysics and slope data (derived from a digital elevation model) were utilized as evidential datalayers. The methods also required the use of point datasets (i.e. soil profiles corresponding to known a.s. or non-a.s. soil occurrences) for training and/or validation within the modeling processes. Applying these methods, various maps were generated: probability maps for a.s. soil occurrence, as well as predictive maps for different soil properties (sulfur content, organic matter content and critical sulfide depth). The two assessed artificial neural networks (ANNs) demonstrated good classification abilities for a.s. soil probability mapping at catchment scale. Slightly better results were achieved using a Radial Basis Function (RBF) -based ANN than a Radial Basis Functional Link Net (RBFLN) method, narrowing down more accurately the most probable areas for a.s. soil occurrence and defining more properly the least probable areas. The RBF-based ANN also demonstrated promising results for the characterization of different soil properties in the most probable a.s. soil areas at catchment scale. Since a.s. soil areas constitute highly productive lands for agricultural purpose, the combination of a probability map with more specific soil property predictive maps offers a valuable toolset to more precisely target strategic areas for subsequent environmental risk management. Notably, the use of laser scanning (i.e. Light Detection And Ranging, LiDAR) data enabled a more precise definition of a.s. soil probability areas, as well as the soil property modeling classes for sulfur content and the critical sulfide depth. Given suitable training/validation points, ANNs can be trained to yield a more precise modeling of the occurrence of a.s. soils and their properties. By contrast, fuzzy logic represents a simple, fast and objective alternative to carry out preliminary surveys, at catchment or regional scale, in areas offering a limited amount of data. This method enables delimiting and prioritizing the most probable areas for a.s soil occurrence, which can be particularly useful in the field. Being easily transferable from area to area, fuzzy logic modeling can be carried out at regional scale. Mapping at this scale would be extremely time-consuming through manual assessment. The use of spatial modeling techniques enables the creation of valid and comparable maps, which represents an important development within the a.s. soil mapping process. The a.s. soil mapping was also assessed using water chemistry data for 24 different catchments along the Finnish coast (in all, covering c. 21,300 km2) which were mapped with different methods (i.e. conventional mapping, fuzzy logic and an artificial neural network). Two a.s. soil related indicators measured in the river water (sulfate content and sulfate/chloride ratio) were compared to the extent of the most probable areas for a.s. soils in the surveyed catchments. High sulfate contents and sulfate/chloride ratios measured in most of the rivers demonstrated the presence of a.s. soils in the corresponding catchments. The calculated extent of the most probable a.s. soil areas is supported by independent data on water chemistry, suggesting that the a.s. soil probability maps created with different methods are reliable and comparable.

Johdon tehtävien merkitys muutosprosessin toteuttamisessa työntekijöiden kokemana - Case: Forssan seudun hyvinvointikuntayhtymä

Sosiaali- ja terveyspalveluiden järjestämisessä Suomessa ollaan muutoksen äärellä. Muutoksilla pyritään palvelujen saatavuuden ja saavutettavuuden turvaamiseen sekä lähipalveluiden varmistamiseen. Nämä muutokset haastavat sosiaali- ja terveydenhuollon johtamistyön muutosprosessien hallintaan. Muutosjohtamisen keskiössä ovat muutosjohtamisen tehtävät ja muutosprosessien onnistuminen, jotta toivotut muutokset saadaan käytäntöön. Tämän tapaustutkimuksen tavoitteena oli selvittää, miten muutosprosessissa johtamisen erilaiset tehtävät ovat yhteydessä muutoksen toteutumiseen, miten tiedottaminen onnistuu muutosprosessissa ja miten työntekijät ovat kokeneet muutosjohtamisen muutosprosessin aikana. Tutkimustapauksena toimi 1.1.2014 Forssan seudun hyvinvointikuntayhtymässä toteutettu organisaatiomuutos. Tutkimuksen kohdejoukkona olivat kliinistä työtä tekevät hoitotyöntekijät. Tutkimus toteutettiin sekä kvantitatiivista että kvalitatiivista tutkimusotetta käyttäen. Empiirinen tutkimusaineisto kerättiin kyselylomakkeella. Kysely lähetettiin 12 eri yksikön hoitotyöntekijöille (N=440) Forssan seudun hyvinvointikuntayhtymässä ja vastausprosentiksi saatiin 44 %. Kvantitatiivinen aineisto kerättiin kyselylomakkeella strukturoiduilla väittämillä ja kvalitatiivinen aineisto kerättiin kyselylomakkeen avoimilla ja puolistrukturoiduilla kysymyksillä. Strukturoidut kysymykset analysoitiin SPSS -ohjelman avulla ja avoimet ja puolistrukturoidut kysymykset analysointiin sisällönanalyysillä. Tutkimuksen tulokset osoittivat, että työntekijöiden kokemukset johdon ja esimiesten toiminnasta muutosprosessissa olivat samansuuntaisia. Työntekijät pitivät tärkeänä, että muutoksen välttämättömyys perustellaan hyvin ja muutoksen tavoitteet esitellään selkeästi. Muutokseen valmistautumiseen tulee varata riittävästi aikaa ja muutos tulee suunnitella hyvin. Työntekijöiden näkemyksen mukaan osallistavien ryhmien kautta olisi ollut mahdollista osallistua muutoksen tekemiseen ja kokea vastuuta muutoksen tekemisestä. Työntekijät odottivat, että johto ja esimiehet palkitsevat heitä muutosprosessissa joustavuudesta ja jaksamisesta. Tulosten perusteella tiedottamisessa ja viestinässä muutosprosessissa tulee kiinnittää huomiota tiedon oikea-aikaisuuteen sekä sen sisältöön. Lisäksi on tärkeää järjestää mahdollisuus lisäinformaation antamiseen. Tiedottamisen ja viestinnän muutosprosessissa koettiin olevan erittäin tärkeä tiedon siirtymisen ja muutosmyönteisyyden kannalta. Tehdyn tapaustutkimuksen perusteella voidaan todeta, että johtamisen tehtävillä voidaan selittää lähes puolet muutoksen onnistumisesta sekä johtajuuden tehtävillä lähes neljännes muutoksen onnistumisesta. Johtamisen tehtävillä on enemmän vaikutusta muutoksen onnistumiseen kuin johtajuuden tehtävillä.

Production of magnesium carbonates from serpentinites for CO2 mineral sequestration : optimisation towards industrial application

Global warming is one of the most alarming problems of this century. Initial scepticism concerning its validity is currently dwarfed by the intensification of extreme weather events whilst the gradual arising level of anthropogenic CO2 is pointed out as its main driver. Most of the greenhouse gas (GHG) emissions come from large point sources (heat and power production and industrial processes) and the continued use of fossil fuels requires quick and effective measures to meet the world’s energy demand whilst (at least) stabilizing CO2 atmospheric levels. The framework known as Carbon Capture and Storage (CCS) – or Carbon Capture Utilization and Storage (CCUS) – comprises a portfolio of technologies applicable to large‐scale GHG sources for preventing CO2 from entering the atmosphere. Amongst them, CO2 capture and mineralisation (CCM) presents the highest potential for CO2 sequestration as the predicted carbon storage capacity (as mineral carbonates) far exceeds the estimated levels of the worldwide identified fossil fuel reserves. The work presented in this thesis aims at taking a step forward to the deployment of an energy/cost effective process for simultaneous capture and storage of CO2 in the form of thermodynamically stable and environmentally friendly solid carbonates. R&D work on the process considered here began in 2007 at Åbo Akademi University in Finland. It involves the processing of magnesium silicate minerals with recyclable ammonium salts for extraction of magnesium at ambient pressure and 400‐440⁰C, followed by aqueous precipitation of magnesium in the form of hydroxide, Mg(OH)2, and finally Mg(OH)2 carbonation in a pressurised fluidized bed reactor at ~510⁰C and ~20 bar PCO2 to produce high purity MgCO3. Rock material taken from the Hitura nickel mine, Finland, and serpentinite collected from Bragança, Portugal, were tested for magnesium extraction with both ammonium sulphate and bisulphate (AS and ABS) for determination of optimal operation parameters, primarily: reaction time, reactor type and presence of moisture. Typical efficiencies range from 50 to 80% of magnesium extraction at 350‐450⁰C. In general ABS performs better than AS showing comparable efficiencies at lower temperature and reaction times. The best experimental results so far obtained include 80% magnesium extraction with ABS at 450⁰C in a laboratory scale rotary kiln and 70% Mg(OH)2 carbonation in the PFB at 500⁰C, 20 bar CO2 pressure for 15 minutes. The extraction reaction with ammonium salts is not at all selective towards magnesium. Other elements like iron, nickel, chromium, copper, etc., are also co‐extracted. Their separation, recovery and valorisation are addressed as well and found to be of great importance. The assessment of the exergetic performance of the process was carried out using Aspen Plus® software and pinch analysis technology. The choice of fluxing agent and its recovery method have a decisive sway in the performance of the process: AS is recovered by crystallisation and in general the whole process requires more exergy (2.48–5.09 GJ/tCO2sequestered) than ABS (2.48–4.47 GJ/tCO2sequestered) when ABS is recovered by thermal decomposition. However, the corrosive nature of molten ABS and operational problems inherent to thermal regeneration of ABS prohibit this route. Regeneration of ABS through addition of H2SO4 to AS (followed by crystallisation) results in an overall negative exergy balance (mainly at the expense of low grade heat) but will flood the system with sulphates. Although the ÅA route is still energy intensive, its performance is comparable to conventional CO2 capture methods using alkanolamine solvents. An energy‐neutral process is dependent on the availability and quality of nearby waste heat and economic viability might be achieved with: magnesium extraction and carbonation levels ≥ 90%, the processing of CO2‐containing flue gases (eliminating the expensive capture step) and production of marketable products.