Development of a process for the direct synthesis of hydrogen peroxide in a novel microstructured reactor

Microreactors have proven to be versatile tools for process intensification. Over recent decades, they have increasingly been used for product and process development in chemical industries. Enhanced heat and mass transfer in the reactors due to the extremely high surfacearea- to-volume ratio and interfacial area allow chemical processes to be operated at extreme conditions. Safety is improved by the small holdup volume of the reactors and effective control of pressure and temperature. Hydrogen peroxide is a powerful green oxidant that is used in a wide range of industries. Reduction and auto-oxidation of anthraquinones is currently the main process for hydrogen peroxide production. Direct synthesis is a green alternative and has potential for on-site production. However, there are two limitations: safety concerns because of the explosive gas mixture produced and low selectivity of the process. The aim of this thesis was to develop a process for direct synthesis of hydrogen peroxide utilizing microreactor technology. Experimental and numerical approaches were applied for development of the microreactor. Development of a novel microreactor was commenced by studying the hydrodynamics and mass transfer in prototype microreactor plates. The prototypes were designed and fabricated with the assistance of CFD modeling to optimize the shape and size of the microstructure. Empirical correlations for the mass transfer coefficient were derived. The pressure drop in micro T-mixers was investigated experimentally and numerically. Correlations describing the friction factor for different flow regimes were developed and predicted values were in good agreement with experimental results. Experimental studies were conducted to develop a highly active and selective catalyst with a proper form for the microreactor. Pd catalysts supported on activated carbon cloths were prepared by different treatments during the catalyst preparation. A variety of characterization methods were used for catalyst investigation. The surface chemistry of the support and the oxidation state of the metallic phase in the catalyst play important roles in catalyst activity and selectivity for the direct synthesis. The direct synthesis of hydrogen peroxide was investigated in a bench-scale continuous process using the novel microreactor developed. The microreactor was fabricated based on the hydrodynamic and mass transfer studies and provided a high interfacial area and high mass transfer coefficient. The catalysts were prepared under optimum treatment conditions. The direct synthesis was conducted at various conditions. The thesis represents a step towards a commercially viable direct synthesis. The focus is on the two main challenges: mitigating the safety problem by utilization of microprocess technology and improving the selectivity by catalyst development.

Combination of pulsed corona discharge with TiO2 photocatalysis: verification of hypothesis

The oxidation potential of pulsed corona discharge concerning aqueous impurities is limited in respect to certain refractory compounds. This may be enhanced in combination of the discharge with catalysis/photocatalysis as developed in homogeneous gas-phase reactions. The objective of the work consists of testing the hypothesis of oxidation potential enhancement in combination of the discharge with TiO2 photocatalysis applied to aqueous solutions of refractory oxalate. Meglumine acridone acetate was included for meeting the practical needs. The experimental research was undertaken into oxidation of aqueous solutions under conditions of various target pollutant concentrations, pH and the pulse repetition rate with plain electrodes and the electrodes with TiO2 attached to their surface. The results showed no positive influence of the photocatalyst, the pollutants were oxidized with the rate identical within the accuracy of measurements. The possible explanation for the observed inefficiency may include low UV irradiance, screening effect of water and generally low oxidation rate in photocatalytic reactions. Further studies might include combination of electric discharge with ozone decomposition/radical formation catalysts.

Production of Chemicals from Woody Biomass by Wet Oxidation

The production of chemicals from sawdust by wet oxidation has been investigated. Two different concentrations of sawdust; 54054 mg/l and 32683 mg/l were used in the study. The wet oxidation operating conditions were; 175 deg.C – 225 deg.C, 1MPa Oxygen, and 40 minutes to 120 minutes reaction time. Carboxylic acids were among the chemicals produced in the process. The total yield of carboxylic acids was found to increase with temperature. Also, higher yields of carboxylic acids were observed at a lower sawdust concentration. This was probably due to the high oxygen-biomass ratio at lower sawdust concentration. Higher oxygen availability at low sawdust concentration resulted in increased conversion of the sawdust; hence the higher yields of carboxylic acids. At lower sawdust concentration, a total carboxylic acid yield of 25.59 wt% was attained at 200 deg.C and 40 minutes reaction time. At higher sawdust concentration, a total carboxylic acid yield of 15.57 wt% was attained at 200 deg.C and 40-minutes reaction time. The carboxylic acids identified include formic acid, acetic acid, succinic acid and oxalic acid. The optimum temperature for the production of formic acid was found to be 200 deg.C, while the optimum temperature for the production of acetic acid was found to be 225 deg.C. A temperature of 225 deg.C and relatively short reaction time of 10 minutes was found to be the optimal condition for the production of succinic acid. Formic acid was produced in the highest yield, with an optimal yield of 13.69wt %, when the reaction temperature and time are 200 deg.C and 40 minutes respectively. The yield of formic acid was found to decrease significantly when further increasing the temperature to 225 deg.C. This was presumably due to thermal decomposition of formic acid at relatively higher temperature. However, the yield of acetic acid was found to steadily increase with temperature. This is because acetic is more thermally stable than formic acid. The yield of acetic acid did not decrease after the temperature was increased to 225 deg.C. Optimal yield of acetic acid (7.98wt %) was achieved at; 225 deg.C, and 40 minutes reaction time. Succinic acid was produced only at temperatures of 200 deg.C and 225 deg.C. Optimal yield of succinic acid (5.66wt %) was attained under the following conditions; 32683 mg/l, 225 deg.C, 1MPa O2, and 10-minutes reaction time. Oxalic acid was produced in the lowest yield and, less frequently. The optimal yield of oxalic acid (4.02 wt%) was attained at 175 deg.C and 80-minutes of reaction time The Total Organic Carbon (TOC) is found to be higher when increasing the operating temperature, thus suggesting that more organic compounds are formed at higher temperatures. The identified carboxylic acids could only account for less than 30% of the measured COD content of the various wet oxidation samples. This implies that some other unidentified compounds (reaction products) must have been present. In general, wet oxidation seems to be an effective method for converting lignocellulosic biomass into useful chemicals. Relatively higher temperatures have been found to favor the production of carboxylic acids from sawdust.

Chromium mass balance in sodium chlorate process

Kuudenarvoista kromia käytetään natriumkloraatin valmistuksessa prosessin tuotantotehokkuuden ja turvallisuuden parantamiseksi. Kromia kuitenkin poistuu prosessista muutamaa reittiä pitkin. Koska kuuudenarvoisella kromilla on syöpää aiheuttavia, mutageenisiä sekä lisääntymiselle myrkyllisiä ominaisuuksia, olisi tärkeää ymmärtää, miten kromi kulkeutuu prosessin eri osiin, ja kuinka paljon sitä poistuu prosessista. Tämä on tärkeää, jotta osataan hallita kromin käytöstä aiheutuvat riskit, sekä toisaalta myös tehostaa kromin käyttöä prosessissa. Työn tarkoituksena oli tuottaa tietoa kromin käytöstä natriumkloraattiprosessissa. Työssä tutkittiin kromitasetta prosessin keskeisimmissä yksikköoperaatioissa. Myös kromin saostumista katodien pinnalle arvioitiin määrällisesti. Eri prosessinäytteistä tutkittiin lisäksi kromin hapetusasteita. Edellä mainittuja tutkimuskohteita varten määritettiin prosessinäytteiden kromipitoisuus. Eri prosessioperaatioille suoritettiin lisäksi taselaskelmat. Työn tuloksena esitettiin kromitase sekä yksikköoperaatioille että koko prosessille. Erinäisten epätarkkuustekijöiden vuoksi tasetta ei kuitenkaan pystytty määrittämään halutulla tarkkuudella, ja siksi työssä esitettyä tasetta voidaan pitää vain suuntaa antavana laskelmana. Katodien pinnalle saostunutta kromin määrää pidettiin kuitenkin oikean suuruusluokan tuloksena. Prosessinäytteiden hapetusasteita ei voitu arvioida, sillä saadut kokonaiskromitulokset eivät olleet täysin luotettavia. Huolimatta tulosten epätarkkuudesta, työ tuotti tärkeää tietoa prosessin toiminnasta kromin suhteen. Työtä voidaan hyödyntää jatkossa monin tavoin prosessin kromitaseen seurannassa.

Advanced analysis and design methods for preparative chromatographic separation processes

Preparative liquid chromatography is one of the most selective separation techniques in the fine chemical, pharmaceutical, and food industries. Several process concepts have been developed and applied for improving the performance of classical batch chromatography. The most powerful approaches include various single-column recycling schemes, counter-current and cross-current multi-column setups, and hybrid processes where chromatography is coupled with other unit operations such as crystallization, chemical reactor, and/or solvent removal unit. To fully utilize the potential of stand-alone and integrated chromatographic processes, efficient methods for selecting the best process alternative as well as optimal operating conditions are needed. In this thesis, a unified method is developed for analysis and design of the following singlecolumn fixed bed processes and corresponding cross-current schemes: (1) batch chromatography, (2) batch chromatography with an integrated solvent removal unit, (3) mixed-recycle steady state recycling chromatography (SSR), and (4) mixed-recycle steady state recycling chromatography with solvent removal from fresh feed, recycle fraction, or column feed (SSR–SR). The method is based on the equilibrium theory of chromatography with an assumption of negligible mass transfer resistance and axial dispersion. The design criteria are given in general, dimensionless form that is formally analogous to that applied widely in the so called triangle theory of counter-current multi-column chromatography. Analytical design equations are derived for binary systems that follow competitive Langmuir adsorption isotherm model. For this purpose, the existing analytic solution of the ideal model of chromatography for binary Langmuir mixtures is completed by deriving missing explicit equations for the height and location of the pure first component shock in the case of a small feed pulse. It is thus shown that the entire chromatographic cycle at the column outlet can be expressed in closed-form. The developed design method allows predicting the feasible range of operating parameters that lead to desired product purities. It can be applied for the calculation of first estimates of optimal operating conditions, the analysis of process robustness, and the early-stage evaluation of different process alternatives. The design method is utilized to analyse the possibility to enhance the performance of conventional SSR chromatography by integrating it with a solvent removal unit. It is shown that the amount of fresh feed processed during a chromatographic cycle and thus the productivity of SSR process can be improved by removing solvent. The maximum solvent removal capacity depends on the location of the solvent removal unit and the physical solvent removal constraints, such as solubility, viscosity, and/or osmotic pressure limits. Usually, the most flexible option is to remove solvent from the column feed. Applicability of the equilibrium design for real, non-ideal separation problems is evaluated by means of numerical simulations. Due to assumption of infinite column efficiency, the developed design method is most applicable for high performance systems where thermodynamic effects are predominant, while significant deviations are observed under highly non-ideal conditions. The findings based on the equilibrium theory are applied to develop a shortcut approach for the design of chromatographic separation processes under strongly non-ideal conditions with significant dispersive effects. The method is based on a simple procedure applied to a single conventional chromatogram. Applicability of the approach for the design of batch and counter-current simulated moving bed processes is evaluated with case studies. It is shown that the shortcut approach works the better the higher the column efficiency and the lower the purity constraints are.

Formation of nitrates in water in presence of formate and oxalate treated with pulsed corona discharge (PCD)

Tavallisten hapetusmenetelmien sijasta kehittyneitä hapetusmenetelmiä (AOP) on kehitetty yhä enemmän, jotta hapetusprosessista tulisi kannattavampi, tehokkaampi, ympäristöystävällisempi ja sitä voitaisiin hyödyntää laajalti eri paikoissa. Uusi teknologia, joka käyttää otsonia ja hydroksyyliradikaalia sähköimpulssien kanssa, on yksi mahdollinen tehokkaampi vedenkäsittelymentelmä. Kyseistä menetelmää kutsutaa pulsed corona discharge (PCD) -menetelmäksi, joka käyttää prosessissa muodostuvia otsonia ja hydroksyyliradikaalia hapettavina tekijöinä. Tässä työssä tutkittiin nitraatin muodostumista vedessä, kun vettä käsiteltiin PCD-laitteessa ja, kun oksalaatti- ja formaatti-ioneja oli sekoittuneina veteen. Nitraatteja muodostuu PCD–laitteessa veteen, kun ilman typpi reagoi hapettimina toimivien otsonin ja hydroksyyliradikaalin kanssa. Aiemmissa tutkimuksissa nitraatin muodostumisen on todistettu parantuvan, kun karboksyylihapot muurahais- ja oksaalihappo ovat sekoittuneina veteen. Tässä tutkimuksessa tarkoituksena oli tutkia, miten formaatti- ja oksalaatti-ionien, joiden pitoisuudet olivat 0 ppm, 50 ppm ja 100 ppm, läsnäolo vedessä vaikuttaa nitraatin muodostumiseen. PCD-kokeista saadut näytteet analysoitiin ionikromatografilla. Kyseisessä tutkimuksessa nitraatin muodostuminen oli samansuuruista jokaisessa kokeessa hapetusajan kasvaessa samalla, kun otettujen näytteiden pH-arvot laskivat. Tuloksena voitiin pitää sitä, ettei formaatti- tai oksalaatti-ioneilla ollut vaikutusta nitraatti-ionien muodostumiseen.

Productizing of advanced service for power plants

Työn tavoitteena on kehittää ABB:lle palvelutuote, jota voidaan tarjota voimalaitosasiakkaille. Uuden palvelutuotteen tulee vastata ABB:n uuden strategian linjauksiin. Palvelulla tarjotaan asiakkaille 1.1.2015 voimaan tulleen energiatehokkuuslain määrittelemien pakollisten toimenpiteiden suoritusta. Työssä kerätään, käsitellään ja analysoidaan tietoa voimalaitosasiakkaille suunnatun palvelun tuotteistamisprosessin päätöksenteon tueksi. Palvelutuotteen kehittämistä varten tutkitaan ABB:n nykyisiä palvelutuotteita, osaamista ja referenssi projekteja, energiatehokkuuslakia, voimalaitosten energiatehokkuus-potentiaalia ja erilaisia energiakatselmusmalleja. Päätöksenteon tueksi tehdään referenssiprojektina energia-analyysi voimalaitokselle, jossa voimalaitoksesta tehdään ipsePRO simulointiohjelmalla mallinnus. Mallinnuksen ja koeajojen avulla tutkitaan voimalaitoksen minimikuorman optimointia. Markkinatutkimuksessa selvitetään lainsäädännön vaikutusta, nykyistä markkinatilannetta, potentiaalisia asiakkaita, kilpailijoita ja ABB:n mahdollisuuksia toimia alalla SWOT–analyysin avulla. Tutkimuksen tulosten perusteella tehdään päätös tuotteistaa voimalaitoksille palvelutuote, joka sisältää kaikki toimet energiatehokkuuslain asettamien vaatimusten täyttämiseen yrityksen energiakatselmuksen vastuuhenkilön, energiakatselmuksen ja kohdekatselmuksien teon osalta. Lisäksi työn aikana Energiavirasto myönsi ABB:lle pätevyyden toimia yrityksen energiakatselmuksen vastuuhenkilönä, mikä on edellytyksenä palvelun tarjoamiselle.

Lignin oxidation by PCD technology

The purpose of this study is to investigate whether commercial Kraft lignin can be treated with pulsed corona discharge apparatus so that it becomes active. Active lignin refers to the kind of lignin that can be precipitated on the surface of a fiber by lowering the pH. A secondary agenda here is to remove the pungent smell of kraft lignin, which is caused by organically bound sulfur. It is expected that the study will identify mild processing conditions and parameters for achievement of the desired outcome. In the literature review, the properties of lignin are explained, as is their impact on any further processing. In addition, a number of processes are described for the oxidation of lignin in a variety of applications. In the experimental part of the study, test runs were conducted to determine the effects of oxygen supply and pulse frequency on oxidation results, where the purpose is to produce reactive lignin and to find a process that is feasible at an industrial scale. Based on the reported experiments, lignin could not be made active or precipitated to the surface of the fiber. Actual changes in the structure of lignin were not observed, but the pungent smell of lignin was removed. The exact reason for this change could not be established because sulfur NMR analysis did not work for the lignin samples.

Utilizing analytic modelling process in industrial retail context

Nykypäivän monimutkaisessa ja epävakaassa liiketoimintaympäristössä yritykset, jotka kykenevät muuttamaan tuottamansa operatiivisen datan tietovarastoiksi, voivat saavuttaa merkittävää kilpailuetua. Ennustavan analytiikan hyödyntäminen tulevien trendien ennakointiin mahdollistaa yritysten tunnistavan avaintekijöitä, joiden avulla he pystyvät erottumaan kilpailijoistaan. Ennustavan analytiikan hyödyntäminen osana päätöksentekoprosessia mahdollistaa ketterämmän, reaaliaikaisen päätöksenteon. Tämän diplomityön tarkoituksena on koota teoreettinen viitekehys analytiikan mallintamisesta liike-elämän loppukäyttäjän näkökulmasta ja hyödyntää tätä mallinnusprosessia diplomityön tapaustutkimuksen yritykseen. Teoreettista mallia hyödynnettiin asiakkuuksien mallintamisessa sekä tunnistamalla ennakoivia tekijöitä myynnin ennustamiseen. Työ suoritettiin suomalaiseen teollisten suodattimien tukkukauppaan, jolla on liiketoimintaa Suomessa, Venäjällä ja Balteissa. Tämä tutkimus on määrällinen tapaustutkimus, jossa tärkeimpänä tiedonkeruumenetelmänä käytettiin tapausyrityksen transaktiodataa. Data työhön saatiin yrityksen toiminnanohjausjärjestelmästä.

Press forming of paperboard – advancement of converting tools and process control

Press forming is nowadays one of the most common industrial methods in use for producing deeper trays from paperboard. Demands for material properties like recyclability and sustainability have increased also in the packaging industry, but there are still limitations related to the formability of paperboard. A majority of recent studies have focused on material development, but the potential of the package manufacturing process can also be improved by the development of tooling and process control. In this study, advanced converting tools (die cutting tools and the press forming mould) are created for production scale paperboard tray manufacturing. Also monitoring methods that enable the production of paperboard trays with enhanced quality, and can be utilized in process control are developed. The principles for tray blank preparation, including creasing pattern and die cutting tool design are introduced. The mould heating arrangement and determination of mould clearance are investigated to improve the quality of the press formed trays. The effect of the spring back of the tray walls on the tray dimensions can be managed by adjusting the heat-related process parameters and estimating it at the mould design stage. This enables production speed optimization as the process parameters can be adjusted more freely. Real-time monitoring of pressing force by using multiple force sensors embedded in the mould structure can be utilized in the evaluation of material characteristics on a modified production machinery. Comprehensive process control can be achieved with a combination of measurement of the outer dimensions of the trays and pressing force monitoring. The control method enables detection of defects and tracking changes in the material properties. The optimized converting tools provide a basis for effective operation of the control system.

Enhancement of ultrafiltration process by pretreatment in recovery of hemicelluloses from wood extracts

Hemicelluloses are potential raw material for several items produced in future wood-based biorefineries. One possible method for recovering hemicelluloses from wood extracts is ultrafiltration (UF). However, low filtration capacities and severe fouling restrict the use of tight UF membranes in the treatment of wood extracts. The lack of suitable commercial membranes creates a need for pretreatment which would decrease fouling and increase the filtration capacity. This thesis focuses on the evaluation of the possibility to improve the filtration capacity and decrease fouling with the pretreatment of wood extracts. Methods which remove harmful compounds and methods which degrade them are studied, as well as combinations of the methods. The tested pretreatments have an influence on both the concentration of different compounds and the molecular mass distribution of the compounds in the extract. This study revealed that in addition to which kind of compounds were removed, also the change in molecular size distribution affected the filtration capacity significantly. It was shown that the most harmful compounds for the filtration capacity of the hydrophobic 5 kDa membrane were the ones capable of permeating the membrane and fouling also the inner membrane structure. Naturally, the size of the most harmful compounds depends on the used UF membrane and is thus case-specific. However, in the choice of the pretreatment method, the focus should be on the removal of harmful compound sizes rather than merely on the total amount of removed foulants. The results proved that filtration capacity can be increased with both adsorptive and oxidative pretreatments even by hundreds of per cents. For instance, the use of XAD7 and XAD16 adsorbents increased the average flux in the UF of a birch extract from nearly zero to 107 kg/(m2h) and 175 kg/(m2h), respectively. In the treatment of a spruce extract, oxidation by pulsed corona discharge (PCD) increased the flux in UF from 46 kg/(m2h) to 158 kg/(m2h). Moreover, when a birch extract batch was treated with laccase enzyme, the flux in UF increased from 15 kg/(m2h) to 36 kg/(m2h). However, fouling was decreased only by adsorptive pretreatment while oxidative methods had a negligible or even negative impact on it. This demonstrates that filtration capacity and fouling are affected by different compounds and mechanisms. The results of this thesis show that filtration capacity can be improved and fouling decreased through appropriate pretreatment. However, the choice of the best possible pretreatment is case-specific and depends on the wood extract and the membrane used. Finding the best option requires information on the extract content and membrane characteristics as well as on the filtration performance of the membrane in the prevailing conditions and a multivariate approach. On the basis of this study, it can be roughly concluded that adsorptive pretreatment improves the filtration capacity and decreases fouling rather reliably, but it may lead to significant hemicellulose losses. Oxidation reduces the loss of valuable hemicelluloses and could improve the filtration capacity, but fouling challenges may remain. Combining oxidation with adsorptive pretreatment was not a solution for avoiding hemicellulose losses in the tested cases.

Perfluorattuja yhdisteitä sisältävien jätevesien puhdistus- ja analyysimenetelmät

Perfluoratut alkyyliyhdisteet eli PFAS-yhdisteet ovat synteettisiä orgaanisia yhdisteitä, joissa on fluorattu hiiliketju. Hiilen ja fluorin väliset vahvat sidokset ovat muodostuneet ongelmaksi jätevedenpuhdistamoilla, sillä yhdisteet eivät hajoa puhdistamoilla käytössä olevilla vedenpuhdistusmenetelmillä. Yhdisteitä kertyy luontoon jätevesien mukana. Kandidaatintyössä on vertailtu yhdisteitä sisältävien vesien käsittelymenetelmiä parhaiten soveltuvan menetelmän löytämiseksi. Menetelmien kustannuksia tai soveltuvuutta vedenpuhdistamomittakaavan prosessiksi ei ole arvioitu. Lisäksi työssä on koottu yhdisteitä sisältävien jätevesien analysointiin sopivia analyysimenetelmiä. Soveltuvat puhdistus- ja analyysimenetelmät on esitelty uusien tieteellisten artikkelien pohjalta. Mahdollisia erotusmenetelmiä ovat membraanierotus ja sorptio. Membraaneista soveltuvimpia ovat nanosuodatus- ja käänteisosmoosimembraanit, joilla erottuvat jopa 0,0001 μm:n kokoiset partikkelit. PFAS-yhdisteet voidaan erottaa sorptiolla muun muassa aktiivihiileen. Yhdisteiden rakenne hajoaa nykyaikaisilla hapetusmenetelmillä ja polttamalla lietteen mukana. Hapettaminen permanganaatin avulla ei tuottanut hyvää tulosta, mutta fotokemiallisella hapetuksella ja alhaisen lämpötilan plasmatekniikalla (NTP) yhdisteiden rakenne hajosi lähes kokonaan. Fotokemiallinen hapetus onnistui erityisesti perfluorokarboksyylihapoilla, joiden rakenne hajosi jopa kolmessa tunnissa. Yleisimmin käytetty analyysimenetelmä on nestekromatografin ja massaspektrometrin yhdistelmä (LC-MS/MS) ja matriisivaikutus minimoidaan tyypillisesti kiinteäfaasiuutolla (SPE). Työssä esitellyistä käsittelymenetelmistä parhaiten soveltuva on NTP-menetelmä, koska sillä saatiin tutkimusten mukaan hajotettua yhdisteiden rakenne muita menetelmiä lyhyemmässä ajassa ja se soveltuu parhaiten kaikille PFAS-yhdisteille. NTP-menetelmässä ei tarvita katalyyttiä tai lisäkemikaaleja. Voimakkaana hapettimena toimivat epästabiilit hydroksyyliradikaalit, jotka syntyvät koronapurkauksen kautta. Koronapurkauksessa muodostuu myös otsonia ja lisäksi vapaa happi voi tehostaa hapettumista. Menetelmässä muodostuvien hajoamistuotteiden hallinta vaatii lisätutkimusta. Mahdollinen hallintakeino voisi olla esimerkiksi hapettumisessa vapautuvien fluoridi-ionien saostaminen. Muodostuvien hajoamistuotteiden toksisuutta voitaisiin tarkkailla biosensorilla.

Development and Effect Analysis of the Asteri Consultative Auditing Process - Safety and Security Management in Educational Institutions

The Finnish legislation requires for a safe and secure learning environment. However, the comprehensive, risk based safety and security management (SSM) and the management commitment in the implementation and development of the SSM are not mentioned in the legislation. Multiple institutions, operators and researchers have studied and developed safety and security in educational institutions over the past decade. Typically the approach has been fragmented and without bringing up the importance of the comprehensive SSM. The development needs of the safety and security operations in universities have been studied. However, in universities of applied sciences (UASs) and in elementary schools (ESs), the performance level, strengths and weaknesses of the comprehensive SSM have not been studied. The objective of this study was to develop the comprehensive, risk based SSM of educational institutions by developing the new Asteri consultative auditing process and study its effects on auditees. Furthermore, the performance level in the comprehensive SSM in UASs and ESs were studied using Asteri and the TUTOR model developed by the Keski-Uusimaa Department for Rescue Services. In addition, strengths, development needs and differences were identified. In total, 76 educational institutions were audited between the years 2011 and 2014. The study is based on logical empiricism, and an observational applied research design was used. Auditing, observation and an electronic survey were used for data collection. Statistical analysis was used to analyze the collected information. In addition, thematic analysis was used to analyze the development areas of the organizations mentioned by the respondents in the survey. As one of the main contributions, this research presents the new Asteri consultative auditing process. Organizations with low performance levels on the audited subject benefit the most from the Asteri consultative auditing process. Asteri may be usable in many different types of audits, not only in SSM audits. As a new result, this study provides new knowledge on attitudes related to auditing. According to the research findings, auditing may generate negative attitudes and the auditor should take them into account when planning and preparing for audits. Negative attitudes can be compensated by producing added value, objectivity and positivity for the audit and, thus, improve the positive effects of auditing on knowledge and skills. Moreover, as the results of this study shows, auditing safety and security issues do not increase feelings of insecurity, but rather increase feelings of safety and security when using the new Asteri consultative auditing process with the TUTOR model. The results showed that the SSM in the audited UASs was statistically significantly more advanced than that in the audited ESs. However, there is still room for improvement in the ESs and the UASs as the approach to the SSM was fragmented. It can be assumed that the majority of Finnish UASs and ESs do not likely meet the basic level of the comprehensive, risk based the SSM.

Ultrasound-assisted electrochemical treatment of wastewaters containing organic pollutants by using novel Ti/Ta2O5-SnO2 electrodes

Advanced oxidation processes (AOPs) are modern methods using reactive hydroxyl radicals for the mineralization of organic pollutants into simple inorganic compounds, such as CO2 and H2O. Among AOPs electrochemical oxidation (EO) is a method suitable for coloured and turbid wastewaters. The degradation of pollutants occurs on electrocatalytic electrodes. The majority of electrodes contain in their structure either expensive materials (diamond and Pt-group metals) or are toxic for the environment compounds (Sb or Pb). One of the main disadvantages of electrochemical method is the polarization and contamination of electrodes due to the deposition of reaction products on their surface, which results in diminishing of the process efficiency. Ultrasound combined with the electrochemical degradation process eliminates electrode contamination because of the continuous mechanical cleaning effect produced by the formation and collapse of acoustic cavitation bubbles near to the electrode surface. Moreover, high frequency ultrasound generates hydroxyl radicals at water sonolysis. Ultrasound-assisted EO is a non-selective method for oxidation of different organic compounds with high degradation efficiencies. The aim of this research was to develop novel sustainable and cost-effective electrodes working as electrocatalysts and test their activity in electrocatalytic oxidation of organic compounds such as dyes and organic acids. Moreover, the goal of the research was to enhance the efficiency of electrocatalytic degradation processes by assisting it with ultrasound in order to eliminate the main drawbacks of a single electrochemical oxidation such as electrodes polarization and passivation. Novel Ti/Ta2O5-SnO2 electrodes were developed and found to be electrocatalytically active towards water (with 5% Ta content, 10 oxide film layers) and organic compounds oxidation (with 7.5% Ta content, 8 oxide film layers) and therefore these electrodes can be applicable in both environmental and energy fields. The synergetic effect of combined electrolysis and sonication was shown while conducting sonoelectrochemical (EO/US) degradation of methylene blue (MB) and formic acid (FA). Complete degradation of MB and FA was achieved after 45 and 120 min of EO/US process respectively in neutral media. Mineralization efficiency of FA over 95% was obtained after 2 h of degradation using high frequency ultrasound (381, 863, 1176 kHz) combined with 9.1 mA/cm2 current density. EO/US degradation of MB provided over 75% mineralization in 8 h. High degradation kinetic rates and mineralization efficiencies of model pollutants obtained in EO/US experiments provide the preconditions for further extrapolation of this treatment method to pilot scale studies with industrial wastewaters.

Possibilities of advanced MAG-welding processes in shipbuilding

In shipbuilding industry welding of primer coated and tack welded steel products cause different issues. Primer coated steel products are commonly used at shipyards to ensure corrosion free storage of products in outdoor conditions. However usage of primer can cause imperfections to welds. To prevent porosity primed steel products are usually welded with tubular welding wires. Tack welds cause commonly interferences in mechanized welding when over welded, which increases costs related to welding due to increased need of preparing and repairing. The aim of this study is to research possibilities of advanced solid wire MAG-welding processes to deal with these two previously mentioned problems. This study concentrates to examine possibilities of MAG-welding, pulse MAG-welding, double pulse MAG-welding, RapidArc and ForceArc processes. Large amount of experiments were made to find out the produced porosity and the ability to over weld tack welds with each process in different circumstances. In welding of primed steel products porosity is caused mainly by hydrogen, CO, CO2, nitrous gases and zinc fumes. It was found in experiments that porosity of MAG-welding can be greatly decreased by using pulse MAG-welding instead. Also reduction of welding speed, usage of air gap and usage of solid wire product with higher amount of alloying elements reduces porosity. Researched advanced MAG-welding processes did not have an improvement into over welding of tack welds. With studied throat thicknesses and welding positions conventional MAG-welding managed better over welding of tack welds than the four studied advanced MAG-welding processes. Studied solid wire MAG-welding processes would be best suited at shipyard for mechanized welding in welding position PB. In welding positions PD and PG tubular welding wires are clearly more productive.