87 resultados para CALCIUM NITRATE SOLUTIONS
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The study evaluates the potential application of chemical substances, obtained from biogas plants` by-products. Through the anaerobic digestion process with biogas the large amount of digestate is produced. This digestate mainly consists on the organic matter with the high concentration of nutrients such as nitrogen and phosphorus. During ammonia stripping and phosphorus precipitation the products- ammonia water, ammonium sulfate, ammonium nitrate, ferrous phosphate, aluminum phosphate, calcium phosphate and struvite can be recovered. These chemicals have potential application in different industrial sectors. According to Finnish market and chemicals properties, the most perspective industrial applications were determined. Based on the data, obtained through the literature review and market study, the ammonia water was recognized as a most perspective recovered substances. According to interview provided among Finnish companies, ammonia water is used for flue gas treatment in SNCR technology. This application has a large scale in the framework of Finnish industrial sectors. As well nitrogen with phosphorous can be used as a source of nutrients in the biological wastewater treatment plants of paper mills.
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Jussi-Pekka Hakkaraisen esitys 24. Kansainvälisessä tieteen-, teknologian ja lääketieteen historian kongressissa (24th International Congress of History of Science, Technology and Medicine) Manchesterissa 26.7.2013
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Papperstillverkningen störs ofta av oönskade föreningar som kan bilda avsättningar på processytor, vilket i sin tur kan ge upphov till störningar i pappersproduktionen samt försämring av papperskvaliteten. Förutom avsättningar av vedharts är stenliknande avlagringar av svårlösliga salter vanliga. I vårt dagliga liv är kalkavlagringar i kaffe- och vattenkokare exempel på liknande problem. I massa- och pappersindustrin är en av de mest problematiska föreningarna kalciumoxalat; detta salt är nästan olösligt i vatten och avlagringarna är mycket svåra att avlägsna. Kalciumoxalat är också känt som en av orsakerna till njurstenar hos människor. Veden och speciellt barken innehåller alltid en viss mängd oxalat men en större källa är oxalsyra som bildas när massan bleks med oxiderande kemikalier, t.ex. väteperoxid. Kalciumoxalat bildas när oxalsyran reagerar med kalcium som kommer in i processen med råvattnet, veden eller olika tillsatsmedel. I denna avhandling undersöktes faktorer som påverkar bildningen av oxalsyra och utfällningen av kalciumoxalat, med hjälp av bleknings- och utfällningsexperiment. Forskningens fokus låg speciellt på olika sätt att förebygga uppkomsten av avlagringar vid tillverkning av trähaltigt papper. Resultaten i denna avhandling visar att bildningen av oxalsyra samt utfällning av kalciumoxalat kan påverkas genom processtekniska och våtändskemiska metoder. Noggrann avbarkning av veden, kontrollerade förhållanden under den alkaliska peroxidblekningen, noggrann hantering och kontroll av andra lösta och kolloidala substanser, samt utnyttjande av skräddarsydd kemi för kontroll av avlagringar är nyckelfaktorer. Resultaten kan utnyttjas då man planerar blekningssekvenser för olika massor samt för att lösa problem orsakade av kalciumoxalat. Forskningsmetoderna som användes i utfällningsstudierna samt för utvärdering av tillsatsmedel kan också utnyttjas inom andra områden, t.ex. bryggeri- och sockerindustrin, där kalciumoxalatproblem är vanligt förekommande. -------------------------------------------- Paperinvalmistusta häiritsevät usein erilaiset epäpuhtaudet, jotka kiinnittyvät prosessipinnoille ja haittaavat tuotantoa sekä paperin laatua. Puun pihkan lisäksi eräs yleinen ongelma on niukkaliukoisten suolojen aiheuttamat kivettymät. Kalkkisaostuma kahvinkeittimessä on esimerkki vastaavasta ongelmasta arkielämässä. Massa- ja paperiteollisuudessa yksi hankalimmista kivettymien muodostajista on kalsiumoksalaatti, koska se on lähes liukenematonta ja sen aiheuttamat saostumat ovat erittäin vaikeasti poistettavia. Kalsiumoksalaatti on yleisesti tunnettu myös munuaiskivien aiheuttajana ihmisillä. Puu ja varsinkin sen kuori sisältää aina jonkin verran oksalaattia, mutta suurempi lähde on kuitenkin oksaalihappo jota muodostuu valkaistaessa massaa hapettavilla kemikaaleilla, kuten vetyperoksidilla. Kalsiumoksalaattia syntyy kun veden, puun ja lisäaineiden mukana prosessiin tuleva kalsium reagoi oksalaatin kanssa. Tässä väitöskirjatyössä tutkittiin oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen vaikuttavia tekijöitä valkaisu- ja saostumiskokeiden avulla. Tutkimuksen painopiste oli saostumien ehkäisemisessä puupitoisten painopaperien valmistuksessa. Työssä saadut tulokset osoittavat että oksaalihapon muodostumiseen ja kalsiumoksalaatin saostumiseen voidaan vaikuttaa sekä prosessiteknisten että märänpään kemian keinojen avulla. Tehokas puun kuorinta, optimoidut olosuhteet peroksidivalkaisussa, muiden liuenneiden ja kolloidisten aineiden hallinta sekä räätälöidyn kemian hyödyntäminen kalsiumoksalaattisaostumien torjunnassa ovat keskeisissä rooleissa ongelmien välttämiseksi. Väitöskirjatyön tuloksia voidaan hyödyntää massan valkaisulinjoja suunniteltaessa sekä kalsiumoksalaatin aiheuttamien ongelmien ratkaisemisessa. Tutkimusmenetelmiä, joita käytettiin saostumiskokeissa ja eri lisäaineiden vaikutusten arvioinnissa, voidaan hyödyntää massa- ja paperiteollisuuden lisäksi myös muilla alueilla, kuten sokeri- ja panimoteollisuudessa, joissa ongelma on myös yleinen.
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Biokuvainformatiikan kehittäminen – mikroskopiasta ohjelmistoratkaisuihin – sovellusesimerkkinä α2β1-integriini Kun ihmisen genomi saatiin sekvensoitua vuonna 2003, biotieteiden päätehtäväksi tuli selvittää eri geenien tehtävät, ja erilaisista biokuvantamistekniikoista tuli keskeisiä tutkimusmenetelmiä. Teknologiset kehitysaskeleet johtivat erityisesti fluoresenssipohjaisten valomikroskopiatekniikoiden suosion räjähdysmäiseen kasvuun, mutta mikroskopian tuli muuntua kvalitatiivisesta tieteestä kvantitatiiviseksi. Tämä muutos synnytti uuden tieteenalan, biokuvainformatiikan, jonka on sanottu mahdollisesti mullistavan biotieteet. Tämä väitöskirja esittelee laajan, poikkitieteellisen työkokonaisuuden biokuvainformatiikan alalta. Väitöskirjan ensimmäinen tavoite oli kehittää protokollia elävien solujen neliulotteiseen konfokaalimikroskopiaan, joka oli yksi nopeimmin kasvavista biokuvantamismenetelmistä. Ihmisen kollageenireseptori α2β1-integriini, joka on tärkeä molekyyli monissa fysiologisissa ja patologisissa prosesseissa, oli sovellusesimerkkinä. Työssä saavutettiin selkeitä visualisointeja integriinien liikkeistä, yhteenkeräytymisestä ja solun sisään siirtymisestä, mutta työkaluja kuvainformaation kvantitatiiviseen analysointiin ei ollut. Väitöskirjan toiseksi tavoitteeksi tulikin tällaiseen analysointiin soveltuvan tietokoneohjelmiston kehittäminen. Samaan aikaan syntyi biokuvainformatiikka, ja kipeimmin uudella alalla kaivattiin erikoistuneita tietokoneohjelmistoja. Tämän väitöskirjatyön tärkeimmäksi tulokseksi muodostui näin ollen BioImageXD, uudenlainen avoimen lähdekoodin ohjelmisto moniulotteisten biokuvien visualisointiin, prosessointiin ja analysointiin. BioImageXD kasvoi yhdeksi alansa suurimmista ja monipuolisimmista. Se julkaistiin Nature Methods -lehden biokuvainformatiikkaa käsittelevässä erikoisnumerossa, ja siitä tuli tunnettu ja laajalti käytetty. Väitöskirjan kolmas tavoite oli soveltaa kehitettyjä menetelmiä johonkin käytännönläheisempään. Tehtiin keinotekoisia piidioksidinanopartikkeleita, joissa oli "osoitelappuina" α2β1-integriinin tunnistavia vasta-aineita. BioImageXD:n avulla osoitettiin, että nanopartikkeleilla on potentiaalia lääkkeiden täsmäohjaussovelluksissa. Tämän väitöskirjatyön yksi perimmäinen tavoite oli edistää uutta ja tuntematonta biokuvainformatiikan tieteenalaa, ja tämä tavoite saavutettiin erityisesti BioImageXD:n ja sen lukuisten julkaistujen sovellusten kautta. Väitöskirjatyöllä on merkittävää potentiaalia tulevaisuudessa, mutta biokuvainformatiikalla on vakavia haasteita. Ala on liian monimutkainen keskimääräisen biolääketieteen tutkijan hallittavaksi, ja alan keskeisin elementti, avoimen lähdekoodin ohjelmistokehitystyö, on aliarvostettu. Näihin seikkoihin tarvitaan useita parannuksia,
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Can crowdsourcing solutions serve many masters? Can they be beneficial for both, for the layman or native speakers of minority languages on the one hand and serious linguistic research on the other? How did an infrastructure that was designed to support linguistics turn out to be a solution for raising awareness of native languages? Since 2012 the National Library of Finland has been developing the Digitisation Project for Kindred Languages, in which the key objective is to support a culture of openness and interaction in linguistic research, but also to promote crowdsourcing as a tool for participation of the language community in research. In the course of the project, over 1,200 monographs and nearly 111,000 pages of newspapers in Finno-Ugric languages will be digitised and made available in the Fenno-Ugrica digital collection. This material was published in the Soviet Union in the 1920s and 1930s, and users have had only sporadic access to the material. The publication of open-access and searchable materials from this period is a goldmine for researchers. Historians, social scientists and laymen with an interest in specific local publications can now find text materials pertinent to their studies. The linguistically-oriented population can also find writings to delight them: (1) lexical items specific to a given publication, and (2) orthographically-documented specifics of phonetics. In addition to the open access collection, we developed an open source code OCR editor that enables the editing of machine-encoded text for the benefit of linguistic research. This tool was necessary since these rare and peripheral prints often include already archaic characters, which are neglected by modern OCR software developers but belong to the historical context of kindred languages, and are thus an essential part of the linguistic heritage. When modelling the OCR editor, it was essential to consider both the needs of researchers and the capabilities of lay citizens, and to have them participate in the planning and execution of the project from the very beginning. By implementing the feedback iteratively from both groups, it was possible to transform the requested changes as tools for research that not only supported the work of linguistics but also encouraged the citizen scientists to face the challenge and work with the crowdsourcing tools for the benefit of research. This presentation will not only deal with the technical aspects, developments and achievements of the infrastructure but will highlight the way in which user groups, researchers and lay citizens were engaged in a process as an active and communicative group of users and how their contributions were made to mutual benefit.
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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014
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In recent decades, industrial activity growth and increasing water usage worldwide have led to the release of various pollutants, such as toxic heavy metals and nutrients, into the aquatic environment. Modified nanocellulose and microcellulose-based adsorption materials have the potential to remove these contaminants from aqueous solutions. The present research consisted of the preparation of five different nano/microcellulose-based adsorbents, their characterization, the study of adsorption kinetics and isotherms, the determination of adsorption mechanisms, and an evaluation of adsorbents’ regeneration properties. The same well known reactions and modification methods that were used for modifying conventional cellulose also worked for microfibrillated cellulose (MFC). The use of succinic anhydride modified mercerized nanocellulose, and aminosilane and hydroxyapatite modified nanostructured MFC for the removal of heavy metals from aqueous solutions exhibited promising results. Aminosilane, epoxy and hydroxyapatite modified MFC could be used as a promising alternative for H2S removal from aqueous solutions. In addition, new knowledge about the adsorption properties of carbonated hydroxyapatite modified MFC as multifunctional adsorbent for the removal of both cations and anions ions from water was obtained. The maghemite nanoparticles (Fe3O4) modified MFC was found to be a highly promising adsorbent for the removal of As(V) from aqueous solutions due to its magnetic properties, high surface area, and high adsorption capacity . The maximum removal efficiencies of each adsorbent were studied in batch mode. The results of adsorption kinetics indicated very fast removal rates for all the studied pollutants. Modeling of adsorption isotherms and adsorption kinetics using various theoretical models provided information about the adsorbent’s surface properties and the adsorption mechanisms. This knowledge is important for instance, in designing water treatment units/plants. Furthermore, the correspondence between the theory behind the model and properties of the adsorbent as well as adsorption mechanisms were also discussed. On the whole, both the experimental results and theoretical considerations supported the potential applicability of the studied nano/microcellulose-based adsorbents in water treatment applications.
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In the design of electrical machines, efficiency improvements have become very important. However, there are at least two significant cases in which the compactness of electrical machines is critical and the tolerance of extremely high losses is valued: vehicle traction, where very high torque density is desired at least temporarily; and direct-drive wind turbine generators, whose mass should be acceptably low. As ever higher torque density and ever more compact electrical machines are developed for these purposes, thermal issues, i.e. avoidance of over-temperatures and damage in conditions of high heat losses, are becoming of utmost importance. The excessive temperatures of critical machine components, such as insulation and permanent magnets, easily cause failures of the whole electrical equipment. In electrical machines with excitation systems based on permanent magnets, special attention must be paid to the rotor temperature because of the temperature-sensitive properties of permanent magnets. The allowable temperature of NdFeB magnets is usually significantly less than 150 ˚C. The practical problem is that the part of the machine where the permanent magnets are located should stay cooler than the copper windings, which can easily tolerate temperatures of 155 ˚C or 180 ˚C. Therefore, new cooling solutions should be developed in order to cool permanent magnet electrical machines with high torque density and because of it with high concentrated losses in stators. In this doctoral dissertation, direct and indirect liquid cooling techniques for permanent magnet synchronous electrical machines (PMSM) with high torque density are presented and discussed. The aim of this research is to analyse thermal behaviours of the machines using the most applicable and accurate thermal analysis methods and to propose new, practical machine designs based on these analyses. The Computational Fluid Dynamics (CFD) thermal simulations of the heat transfer inside the machines and lumped parameter thermal network (LPTN) simulations both presented herein are used for the analyses. Detailed descriptions of the simulated thermal models are also presented. Most of the theoretical considerations and simulations have been verified via experimental measurements on a copper tooth-coil (motorette) and on various prototypes of electrical machines. The indirect liquid cooling systems of a 100 kW axial flux (AF) PMSM and a 110 kW radial flux (RF) PMSM are analysed here by means of simplified 3D CFD conjugate thermal models of the parts of both machines. In terms of results, a significant temperature drop of 40 ̊C in the stator winding and 28 ̊C in the rotor of the AF PMSM was achieved with the addition of highly thermally conductive materials into the machine: copper bars inserted in the teeth, and potting material around the end windings. In the RF PMSM, the potting material resulted in a temperature decrease of 6 ̊C in the stator winding, and in a decrease of 10 ̊C in the rotor embedded-permanentmagnets. Two types of unique direct liquid cooling systems for low power machines are analysed herein to demonstrate the effectiveness of the cooling systems in conditions of highly concentrated heat losses. LPTN analysis and CFD thermal analysis (the latter being particularly useful for unique design) were applied to simulate the temperature distribution within the machine models. Oil-immersion cooling provided good cooling capability for a 26.6 kW PMSM of a hybrid vehicle. A direct liquid cooling system for the copper winding with inner stainless steel tubes was designed for an 8 MW directdrive PM synchronous generator. The design principles of this cooling solution are described in detail in this thesis. The thermal analyses demonstrate that the stator winding and the rotor magnet temperatures are kept significantly below their critical temperatures with demineralized water flow. A comparison study of the coolant agents indicates that propylene glycol is more effective than ethylene glycol in arctic conditions.
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In this thesis, stepwise titration with hydrochloric acid was used to obtain chemical reactivities and dissolution rates of ground limestones and dolostones of varying geological backgrounds (sedimentary, metamorphic or magmatic). Two different ways of conducting the calculations were used: 1) a first order mathematical model was used to calculate extrapolated initial reactivities (and dissolution rates) at pH 4, and 2) a second order mathematical model was used to acquire integrated mean specific chemical reaction constants (and dissolution rates) at pH 5. The calculations of the reactivities and dissolution rates were based on rate of change of pH and particle size distributions of the sample powders obtained by laser diffraction. The initial dissolution rates at pH 4 were repeatedly higher than previously reported literature values, whereas the dissolution rates at pH 5 were consistent with former observations. Reactivities and dissolution rates varied substantially for dolostones, whereas for limestones and calcareous rocks, the variation can be primarily explained by relatively large sample standard deviations. A list of the dolostone samples in a decreasing order of initial reactivity at pH 4 is: 1) metamorphic dolostones with calcite/dolomite ratio higher than about 6% 2) sedimentary dolostones without calcite 3) metamorphic dolostones with calcite/dolomite ratio lower than about 6% The reactivities and dissolution rates were accompanied by a wide range of experimental techniques to characterise the samples, to reveal how different rocks changed during the dissolution process, and to find out which factors had an influence on their chemical reactivities. An emphasis was put on chemical and morphological changes taking place at the surfaces of the particles via X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). Supporting chemical information was obtained with X-Ray Fluorescence (XRF) measurements of the samples, and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) measurements of the solutions used in the reactivity experiments. Information on mineral (modal) compositions and their occurrence was provided by X-Ray Diffraction (XRD), Energy Dispersive X-ray analysis (EDX) and studying thin sections with a petrographic microscope. BET (Brunauer, Emmet, Teller) surface areas were determined from nitrogen physisorption data. Factors increasing chemical reactivity of dolostones and calcareous rocks were found to be sedimentary origin, higher calcite concentration and smaller quartz concentration. Also, it is assumed that finer grain size and larger BET surface areas increase the reactivity although no certain correlation was found in this thesis. Atomic concentrations did not correlate with the reactivities. Sedimentary dolostones, unlike metamorphic ones, were found to have porous surface structures after dissolution. In addition, conventional (XPS) and synchrotron based (HRXPS) X-ray Photoelectron Spectroscopy were used to study bonding environments on calcite and dolomite surfaces. Both samples are insulators, which is why neutralisation measures such as electron flood gun and a conductive mask were used. Surface core level shifts of 0.7 ± 0.1 eV for Ca 2p spectrum of calcite and 0.75 ± 0.05 eV for Mg 2p and Ca 3s spectra of dolomite were obtained. Some satellite features of Ca 2p, C 1s and O 1s spectra have been suggested to be bulk plasmons. The origin of carbide bonds was suggested to be beam assisted interaction with hydrocarbons found on the surface. The results presented in this thesis are of particular importance for choosing raw materials for wet Flue Gas Desulphurisation (FGD) and construction industry. Wet FGD benefits from high reactivity, whereas construction industry can take advantage of slow reactivity of carbonate rocks often used in the facades of fine buildings. Information on chemical bonding environments may help to create more accurate models for water-rock interactions of carbonates.
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Presentation of Janet Aucock, at the FinELib Consortium Seminar (Aineistopäivä), April 16, 2015 in Helsinki.
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Litiumioniakkujen kehityksen myötä litiumin tarve ja kysyntä ovat kasvaneet viime vuodet tasaisesti noin 10 % vuosivauhdilla. Kasvun on myös ennustettu jatkuvan samanlaisena tulevaisuudessa, jonka takia erilaiset litiumin erotusprosessit ovat nousseet tutkimuksen kohteeksi. Tärkeimmät litiumlähteet sijaitsevat suola-aavikoilla ja -järvillä, joihin litiumia on kerääntynyt suuria määriä maanpinnan läheisyyteen. Litiumia erotetaan suolatasangoilla aikaa vievissä haihdutus- ja saostusvaiheissa. Suolaliuokset sisältävät litiumin lisäksi muita metalleja, kuten magnesiumia, kalsiumia ja natriumia, joista etenkin magnesium häiritsee litiumin erotusta. Aikaisemmissa tutkimuksissa ei ole löydetty litiumille riittävän selektiivistä ioninvaihtohartsia. Tehdyissä tutkimuksissa muut metallit on usein erotettu selektiivisesti ennen litiumia ja litium on erotettu lopuksi. Litiumin erotusta voitaisiin parantaa, mikäli se onnistuisi selektiivisesti suoraan suolaliuoksesta. Tässä työssä tutkittiin litiumin selektiivistä erotusta magnesium- ja kalsiumpitoisesta väkevästä kloridiliuoksesta ioninvaihtohartseilla sekä molekyyliseulalla. Käytetyt neljä ioninvaihtohartsia olivat kaupallisia Puroliten hartseja: MN200, S940, CT151 ja A170. Molekyyliseula oli Sigman huokoskoon 4 Å zeoliittia. Kromatografisilla kolonnikokeilla saadut näytteet analysoitiin ICP-AES:lla. Tulosten perusteella ei yksikään tutkituista hartseista ja molekyyliseulasta ollut selektiivinen litiumille.
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Crystal properties, product quality and particle size are determined by the operating conditions in the crystallization process. Thus, in order to obtain desired end-products, the crystallization process should be effectively controlled based on reliable kinetic information, which can be provided by powerful analytical tools such as Raman spectrometry and thermal analysis. The present research work studied various crystallization processes such as reactive crystallization, precipitation with anti-solvent and evaporation crystallization. The goal of the work was to understand more comprehensively the fundamentals, phenomena and utilizations of crystallization, and establish proper methods to control particle size distribution, especially for three phase gas-liquid-solid crystallization systems. As a part of the solid-liquid equilibrium studies in this work, prediction of KCl solubility in a MgCl2-KCl-H2O system was studied theoretically. Additionally, a solubility prediction model by Pitzer thermodynamic model was investigated based on solubility measurements of potassium dihydrogen phosphate with the presence of non-electronic organic substances in aqueous solutions. The prediction model helps to extend literature data and offers an easy and economical way to choose solvent for anti-solvent precipitation. Using experimental and modern analytical methods, precipitation kinetics and mass transfer in reactive crystallization of magnesium carbonate hydrates with magnesium hydroxide slurry and CO2 gas were systematically investigated. The obtained results gave deeper insight into gas-liquid-solid interactions and the mechanisms of this heterogeneous crystallization process. The research approach developed can provide theoretical guidance and act as a useful reference to promote development of gas-liquid reactive crystallization. Gas-liquid mass transfer of absorption in the presence of solid particles in a stirred tank was investigated in order to gain understanding of how different-sized particles interact with gas bubbles. Based on obtained volumetric mass transfer coefficient values, it was found that the influence of the presence of small particles on gas-liquid mass transfer cannot be ignored since there are interactions between bubbles and particles. Raman spectrometry was successfully applied for liquid and solids analysis in semi-batch anti-solvent precipitation and evaporation crystallization. Real-time information such as supersaturation, formation of precipitates and identification of crystal polymorphs could be obtained by Raman spectrometry. The solubility prediction models, monitoring methods for precipitation and empirical model for absorption developed in this study together with the methodologies used gives valuable information for aspects of industrial crystallization. Furthermore, Raman analysis was seen to be a potential controlling method for various crystallization processes.
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Purpose of this study is to clarify the industrial solutions purchasing process from purchaser companies’ point of view. Also customer’s view on value generating aspects and difficulties in purchases will be discussed as well as different purchas-ing entities where customers have ended up in their solution purchases. Current solution literature is mainly concentrated in supplier views and customer perspec-tive has been left without adequate attention. However, knowledge of the customer and the identification of customer need are at the core of a successful solution business. The focus of this thesis is on Finnish companies’ solution purchases that have been realized during last five years. Industrial solutions in this case are facto-ries or other large industrial plants. Industrial solutions’ purchasing process will be opened all the way from discovering the need until the start-up of the plant. Of in-terest is the customer experience of the success of the acquisition and the pur-chaser’s view on good practices allowing a successful procurement project.