APLICAÇÃO DE ÓXIDOS DE FERRO NANOESTRUTURADOS COMO ADSORVENTES E FOTOCATALISADORES NA REMOÇÃO DE POLUENTES DE ÁGUAS RESIDUAIS

New techniques for treating wastewater, particularly the removal or degradation of organic pollutants and heavy metals, among other pollutants, have been extensively studied. The use of nanostructured iron oxides as adsorbent and photocatalyst for the removal of these contaminants has proved a promising approach, not only because of their high treatment efficiency, but also for their cost-effectiveness, having the flexibility for in situ and ex situ applications. In this review, we briefly introduced the most used kinds of iron oxide nanoparticles, some synthesis techniques for iron oxide nanostructure formation, their potential benefits in environmental clean-up, and their recent advances and applications in wastewater treatment. These advances range from the direct applications of synthesized nanoparticles as adsorbents for removing toxic contaminants or as catalysts to oxidize and break down noxious contaminants (including bacteria and viruses) in wastewater, to integrating nanoparticles into conventional treatment technologies, such as composite photocatalytic filters (membranes, sand and ceramic) that combine separation technology with photocatalytic activity. Finally, the impact of nanoparticles on the environment and human health is briefly discussed.

FASES ESTACIONÁRIAS DE LÍQUIDOS IÔNICOS EM CROMATOGRAFIA GASOSA: FUNDAMENTOS, AVANÇOS RECENTES E PERSPECTIVAS

Since their original discovery in 1914, ionic liquids (IL) have been widely examined and explored in chemistry due to their unique physical and chemical properties. Ionic liquids are collectively known as organic salts and have melting points of 100 °C or under. The molten salts most employed in analytical chemistry, including gas chromatography (GC), consist of an organic cation paired with an organic or inorganic anion. This class of materials exhibits negligible vapor pressure and may have their properties (e.g.thermal stability and selectivity) structurally tuned by imparting different moieties to the cation/anion. Currently, there are an estimated 1018possible combinations of IL. In this context, the prospection of highly selective IL-based stationary phases for gas-liquid chromatography has enabled high peak capacity and efficient separations of many critical pairs in complex samples. In this review, we present and discuss fundamental characteristics of ionic liquids and introduce important solvation models for gas-liquid systems. In addition, recent advances and applications of IL in conventional and multidimensional gas chromatography are outlined.

Täystehokonvertterin tehohäviöt ja hyötysuhde

Diplomityössä perehdytään tuuliturbineissa käytettyjen täystehokonvertterien tehohäviöihin ja hyötysuhteeseen. Täystehokonvertterissa generaattorin tuottama sähköteho tasasuunnataan hyvällä hyötysuhteella aktiivisella geenraattorisillalla konvertterin välipiiriin ja edelleen vaihtosuunnataan aktiivisella verkkovaihtosuuntaajasillalla siirtoverkkoon. Työn tarkoituksena on antaa yleiskuva tehohäviöiden jakautumisesta ja yksinkertaistaa niiden laskentaa. Häviömekanismit ja häviöiden määräytyminen esitellään pääkomponenttitasolla. Tehohäviöiden osalta keskitytään erityisesti muuntajateräksestä valmistettujen sinisuotimien ja du/dt-suotimien rautahäviöihin. Ongelmana rautahäviöiden määrittämisessä on korkeilla taajuuksilla tapahtuvat häviöt, joiden laskentaan ei ole yleensä saatavilla tarvittavia materiaaliparametrejä. Tehohäviöiden laskentaa varten toteutettu laskentasovellus on esitelty periaatteellisina vuokaavioina ja sovelluksella saatavia tuloksia on esitetty ja vertailtu mitattuihin tuloksiin.

Microwave Processes in Ferrite-ferroelectric Layered Structure

This work is devoted to investigation of wave processes in new hybrid ferrite/ferroelectric structures. Spin wave devices based on ferrite films have disadvanteges. And their applications are limited. Investigated structures allow to overcome disadvantages. This investigation helps to create new class of devices. Electromagnetic analysis of hybrid spin-electromagnetic waves in ferrite/ferroelectric structures were done. As a result dispersion relation was found. Numerical solution of this dispersion relation gave us follow results. These structures can be effectively tuned by external electric and magnetic field. Methods to increase tuning range were suggested. It was found that such structures have one basic disadvantage which is connected with presence of thick ferroelectric layer. To solve this problem is to use thin ferroelectric films. But this decreases tuning range. It was confirmed by experiment that this structures can be effectively tuned by electric and magnetic fields. Resonance characteristics of ferrite/ferroelectric resonator were succesfully tuned by magnetic and electric field.

Autosimulaattoripeleihin soveltuvan kaksiakselisen liikealustan kehittäminen

Työssä kehitettiin kohtuuhintainen ja suorituskyvyltään riittävä autosimulaattoripelikäyttöön soveltuva liikealusta. Työssä tutustuttiin aluksi markkinoilla oleviin liikealustaratkaisuihin. Työssä selvitettiin myös liikealustaa koskevia turvallisuusmääräyksiä. Kehittäminen alkoi liikealustan vaatimusten määrittelyllä ja kuormituksien simuloinnilla. Runkorakenteet mitoitettiin kestämään simuloituja rasituksia. Liikealustan toimilaitteet valittiin simulointitulosten perusteella. Työssä suunniteltiin myös liikealustan ohjausjärjestelmä. Mekaanisien osien ja voimansiirron mitoittamisen jälkeen suoritettiin osien yksityiskohtainen suunnittelu. Alihankkijat valmistivat osat ja ne koottiin Älykkäiden koneiden laboratoriossa. Järjestelmän kokoamisen jälkeen viritettiin säätäjät ja testattiin liikealustan toimivuutta. Kehitettyä liikealustaa on käytetty muutamissa tapahtumissa. Asetetut tavoitteet saavutettiin ja liikealusta soveltuu kokemuksien perusteella hyvin rata-autosimulaattoripelien kanssa käytettäväksi.

Line filter optimization in elevator use

The purpose of this thesis was to create design a guideline for an LCL-filter. This thesis reviews briefly the relevant harmonics standards, old filter designs and problems faced with the previous filters. This thesis proposes a modified design method based on the “Liserre’s method” presented in the literature. This modified method will take into account network parameters better. As input parameters, the method uses the nominal power, allowed ripple current in converter and network side and desired resonant frequency of the filter. Essential component selection issues for LCL-filter, such as heating, voltage strength, current rating etc. are also discussed. Furthermore, a simulation model used to verify the operation of the designed filter in nominal power use and in transient situations is included in this thesis.

Production planning development in global manufacturing company

Larox Corporation is a provider of full service filtration in solid and liquid separation. Larox develops, designs, manufactures and supplies industrial filters. By Larox’s continuous development principle, a project for more efficient production was started. At the same time production planning was taken under review. Aim for this Master’s thesis was to find software designed for production planning purposes replacement for old Microsoft Excel based method. In this Master’s thesis current way of production planning was thoroughly analyzed and improvement targets were specified and also requirements for new software were assigned. Primary requirements for new software were possibility to production scheduling, planning, follow-up and also for long-time capacity planning and tracking. Also one demand was that new software should have data link to Larox’s current ERP-system. Result of this Master’s thesis was to start using Larox’s ERP-system also for production planning purposes. New mode of operation fulfils all requirements which were placed to new system. By using new method of production planning, production planners can get more easier and reliable data than from current system.

Online Ultrasound Measurements of Membrane Compaction

There are several filtration applications in the pulp and paper industry where the capacity and cost-effectiveness of processes are of importance. Ultrafiltration is used to clean process water. Ultrafiltration is a membrane process that separates a certain component or compound from a liquid stream. The pressure difference across the membrane sieves macromolecules smaller than 0.001-0.02 μm through the membrane. When optimizing the filtration process capacity, online information about the conditions of the membrane is needed. Fouling and compaction of the membrane both affect the capacity of the filtration process. In fouling a “cake” layer starts to build on the surface of the membrane. This layer blocks the molecules from sieving through the membrane thereby decreasing the yield of the process. In compaction of the membrane the structure is flattened out because of the high pressure applied. The higher pressure increases the capacity but may damage the structure of the membrane permanently. Information about the compaction is needed to effectively operate the filters. The objective of this study was to develop an accurate system for online monitoring of the condition of the membrane using ultrasound reflectometry. Measurements of ultrafiltration membrane compaction were made successfully utilizing ultrasound. The results were confirmed by permeate flux decline, measurements of compaction with a micrometer, mechanical compaction using a hydraulic piston and a scanning electron microscope (SEM). The scientific contribution of this thesis is to introduce a secondary ultrasound transducer to determine the speed of sound in the fluid used. The speed of sound is highly dependent on the temperature and pressure used in the filters. When the exact speed of sound is obtained by the reference transducer, the effect of temperature and pressure is eliminated. This speed is then used to calculate the distances with a higher accuracy. As the accuracy or the resolution of the ultrasound measurement is increased, the method can be applied to a higher amount of applications especially for processes where fouling layers are thinner because of smaller macromolecules. With the help of the transducer, membrane compaction of 13 μm was measured in the pressure of 5 bars. The results were verified with the permeate flux decline, which indicated that compaction had taken place. The measurements of compaction with a micrometer showed compaction of 23–26 μm. The results are in the same range and confirm the compaction. Mechanical compaction measurements were made using a hydraulic piston, and the result was the same 13 μm as obtained by applying the ultrasound time domain reflectometry (UTDR). A scanning electron microscope (SEM) was used to study the structure of the samples before and after the compaction.

Henkilötason suorituskykymittariston suunnittelu asiantuntijayrityksessä

Suorituskyvyn mittaaminen on tehokas työkalu yrityksen toiminnan kehittämiseen. Mittarit ohjaavat yritystä keskittymään strategian ja tavoitteiden toteuttamiseen. Yrityksen suorituskykyä tarkastellaan usein erityisesti yritystasolla, mutta mittarit voidaan myös kohdentaa yksittäisille työntekijöille. Työn tavoitteena oli löytää jo suunnitteluvaiheessa huomioitavia menestystekijöitä pienen asiantuntijayrityksen henkilötason suorituskykymittaristolle. Tutkimuskysymyksiin vastaamiseksi käytettiin kirjallisuuden lisäksi kohdeyritykselle toteutettua suunnitteluprosessia, jossa hyödynnettiin myös yrityksen henkilöstön näkemyksiä. Merkittävimmät erityispiirteet mittariston suunnittelussa liittyivät asiantuntijatyön mittaukseen, mittariston resurssitarpeen minimoimiseen ja palkitsemiseen suorituskyvyn perusteella. Lisäksi työssä pohdittiin suunnitellun mittariston laajentamismahdollisuuksia yritystason mittaristoksi. Suorituskyvyn mittaaminen tehostaa yrityksen päätöksentekoa sekä viestintää. Laadukas mittaristo edellyttää myös hyvää suunnittelua, joka voidaan perustaa kirjallisuuden malleihin. Johdon ja henkilöstön sitoutuminen suunnitteluprosessiin on kriittistä onnistuneen mittariston kannalta. Mittariston suunnittelussa mittarit johdetaan yleensä yrityksen visiosta strategian, mittausalueiden ja menestystekijöiden kautta. Mittareiden painotuksia muuttamalla voidaan hienosäätää mittariston vaikutusta. Mittariston koekäyttövaiheessa todetaan mittariston toimivuus ennen mittareiden kytkemistä tulospalkkioihin. Asiantuntijatyön mittauksessa on kiinnitettävä huomiota toimivien mittareiden löytämiseen, sillä tietopohjaista asiantuntijatyötä on haastava mitata. Lisäksi palkitsemisjärjestelmän liittäminen mittaristoon edellyttää mittareilta ehdotonta oikeudenmukaisuutta ja tuloksia ei saa pystyä manipuloimaan. Pienen yrityksen mittaristo ei saa kuluttaa liikaa resursseja, joten kannattaa suosia mahdollisimman itsenäisesti toimivia mittareita. Henkilöstön motivointi tietojen syöttöön on olennaista. Lisäksi objektiivisten ja olennaisten mittareiden käyttö vähentää mittariston ylläpitoon käytettyjä työtunteja. Henkilötason mittaristo voidaan laajentaa helposti myös yritystasolle, mikäli suunnittelussa on kiinnitetty huomiota huolelliseen dokumentointiin.

Solving Challenging Real-World Scheduling Problems

This work contains a series of studies on the optimization of three real-world scheduling problems, school timetabling, sports scheduling and staff scheduling. These challenging problems are solved to customer satisfaction using the proposed PEAST algorithm. The customer satisfaction refers to the fact that implementations of the algorithm are in industry use. The PEAST algorithm is a product of long-term research and development. The first version of it was introduced in 1998. This thesis is a result of a five-year development of the algorithm. One of the most valuable characteristics of the algorithm has proven to be the ability to solve a wide range of scheduling problems. It is likely that it can be tuned to tackle also a range of other combinatorial problems. The algorithm uses features from numerous different metaheuristics which is the main reason for its success. In addition, the implementation of the algorithm is fast enough for real-world use.

Hammashihnajohdeakseleiden liikkeiden synkronointi

Nykyisessä valmistusteollisuudessa erilaisten robottien ja automatisoitujen tuotantovaiheiden rooli on erittäin merkittävä. Tarkasti suunnitellut liikkeet ja toimintavaiheet voidaan nykyisillä järjestelmillä ajoittaa tarkasti toisiinsa nähden, jolloin erilaisten virhetilanteidenkin sattuessa järjestelmä pystyy toimimaan tilanteen edellyttämällä tavalla. Automatisoinnin etuna on myös tuotannon muokkaaminen erilaisten tuotteiden valmistamiseen pienillä muutoksilla, jolloin tuotantokustannukset pysyvät matalina myös pienten valmistuserien tapauksissa. Usean akselin laitteissa eli niin sanotuissa moniakselikäytöissä laitteen toimintatarkkuus riippuu jokaisen liikeakselin tarkkuudesta. Liikkeenohjauksessa on perinteisesti ollut käytössä myötäkytketty paikkakaskadi, jonka virityksessä otetaan huomioon akselilla olevat erilaiset dynaamiset tilat ja käytettävät referenssit. Monissa nykyisissä hajautetuissa järjestelmissä eli moniakselikäytöissä, joissa jokaiselle akselille on oma ohjauslaite, ei yksittäisen akselin paikkavirhettä huomioida muiden akseleiden ohjauksessa. Työssä tutkitaan erilaisia moniakselijärjestelmien ohjausmenetelmiä ja myötäkytketyn paikkakaskadin toimintaa moniakselikäytössä pyritään parantamaan tuomalla paikkasäätimen rinnalle toinen säädin, jonka tulona on akseleiden välinen paikkaero.

Effectiveness of Pilotage

The objective of the pilotage effectiveness study was to come up with a process descrip-tion of the pilotage procedure, to design performance indicators based on this process description, to be used by Finnpilot, and to work out a preliminary plan for the imple-mentation of the indicators within the Finnpilot organisation. The theoretical aspects of pilotage as well as the guidelines and standards used were determined through a literature review. Based on the literature review, a process flow model with the following phases was created: the planning of pilotage, the start of pilo-tage, the act of pilotage, the end of pilotage and the closing of pilotage. The model based on the literature review was tested through interviews and observation of pilotage. At the same time an e-mail survey directed at foreign pilotage organisations, which included a questionnaire concerning their standards and management systems, operations procedures, measurement tools and their attitude to the passage planning, was conducted. The main issues in the observations and interviews were the passage plan and the bridge team co-operation. The phases of the pilotage process model emerged in both the pilotage activities and the interviews whereas bridge team co-operation was relatively marginal. Most of the pilotage organisations, who responded to the query, also use some standard-based management system. All organisations who answered the survey use some sort of a pilotage process model. According to the query, the main measuring tools for pilotage are statistical information concerning pilotage and the organisations, the customer feedback surveys, and financial results. Attitudes to-wards passage planning were mostly positive among the organisations. A workshop with pilotage experts was arranged where the process model constructed on the basis of the literature review was tuned to match practical pilotage. In the workshop it was determined that certain phases and the corresponding tasks, through which pilo-tage can be described as a process, were identifiable in all pilotage. The result of the workshop was a complemented process model, which separates incoming and outgoing traffic, as well as the fairway pilotage and harbour pilotage from each other. Addition-ally indicators divided according to the data gathering method were defined. Data con-cerning safety and traffic flow is gathered in the form of customer feedback. The pilot's own perceptions of the pilotage process are gathered through self-assessment. The measurement data which is connected to the phases of the pilotage process is generated e.g. by gathering statistics of the success of the pilot dispatches, the accuracy of the pi-lotage and the incidents that occurred during the pilotage, near misses, deviations and accidents. The measurement data is collected via the PilotWeb at the closing of the pilo-tage. A separate project and a project group with pilots also participating will be established for the deployment of the performance indicators. The phases of the project are: the definition phase, the implementation phase and the deployment phase. The purpose of the definition phase is to prepare questions for ship commanders concerning the cus-tomer feedback questionnaire and also to work out the self-assessment queries and the queries concerning the process indicators.

Water treatment by multistage filtration system with natural coagulant from Moringa oleifera seeds

This study presents an evaluation of a pilot multistage filtration system (MSF) with different dosages, 131 mg L-1 and 106 mg L-1, of the natural coagulant extracted from Moringa oleifera seeds in pre-filtration and slow filtration stages, respectively. The system was comprised by a dynamic pre-filter unit, two upflow filters in parallel and four slow filters in parallel, and in one of the four filters had the filter media altered. The performance of the system was evaluated by monitoring some water quality parameters such as: turbidity, apparent color and slow filter load loss. The stages that have received the coagulant solution had better treatment efficiency compared with the steps without it. However, the direct application of the coagulant solution in the slow filter caused rapid clogging of the non-woven blanket and shorter career length.

Periodic inspection of sprayers: diagnostic to the northern of Paraná

To optimize the use of pesticides, several countries have carried out periodic inspections in agricultural sprayers. In Brazil, knowing the conditions of this machinery canguide researches and investments in guidelines for its use and maintenance. The objective of this study was to verify the state of sprayer maintenance used in the North of the state of Paraná, in Brazil. Several sprayer items were evaluated, such as: presence, status and scale of the manometer, status of the hose, status of the anti-drip component, presence of leaks, status of the bar, status of the filters, state of the spraying nozzles and errors in the targeted flow rate. Machines were named as approved when there was no failure in any item evaluated. The factor that caused the biggest level of reprove among the machines was incorrect scale of manometers, which reproved 84.55% of the machines evaluated. Other outstanding factor was the incorrect flow rate in 75.5% of the tested machines. Only one unit was approved from the total of 110 evaluated sprayers.

Ion selective electrodes for determination of low and ultra low concentrations of lead (II) in natural waters

Att övervaka förekomsten av giftiga komponenter i naturliga vattendrag är nödvändigt för människans välmående. Eftersom halten av föroreningar i naturens ekosystem bör hållas möjligast låg, pågår en ständig jakt efter kemiska analysmetoder med allt lägre detektionsgränser. I dagens läge görs miljöanalyser med dyr och sofistikerad instrumentering som kräver mycket underhåll. Jonselektiva elektroder har flera goda egenskaper som t.ex. bärbarhet, låg energiförbrukning, och dessutom är de relativt kostnadseffektiva. Att använda jonselektiva elektroder vid miljöanalyser är möjligt om deras känslighetsområde kan utvidgas genom att sänka deras detektionsgränser. För att sänka detektionsgränsen för Pb(II)-selektiva elektroder undersöktes olika typer av jonselektiva membran som baserades på polyakrylat-kopolymerer, PVC och PbS/Ag2S. Fast-fas elektroder med membran av PbS/Ag2S är i allmänhet enklare och mer robusta än konventionella elektroder vid spårämnesanalys av joniska föroreningar. Fast-fas elektrodernas detektionsgräns sänktes i detta arbete med en nyutvecklad galvanostatisk polariseringsmetod och de kunde sedan framgångsrikt användas för kvantitativa bestämningar av bly(II)-halter i miljöprov som hade samlats in i den finska skärgården nära tidigare industriområden. Analysresultaten som erhölls med jonselektiva elektroder bekräftades med andra analytiska metoder. Att sänka detektionsgränsen m.hj.a. den nyutvecklade polariseringsmetoden möjliggör bestämning av låga och ultra-låga blyhalter som inte kunde nås med klassisk potentiometri. Den verkliga fördelen med att använda dessa blyselektiva elektroder är möjligheten att utföra mätningar i obehandlade miljöprov trots närvaron av fasta partiklar vilket inte är möjligt att göra med andra analysmetoder. Jag väntar mig att den nyutvecklade polariseringsmetoden kommer att sätta en trend i spårämnesanalys med jonselektiva elektroder.