Ion modulated organic transistors

I likhet med vanliga plaster är de π-konjugerade polymererna flexibla, lösliga och processbara vid låga temperaturer (< 150 ºC). Därutöver har de egenskapen att leda ström. Konduktivitetsintervallet är brett och omfattar nästintill metallisk ledningsförmåga å ena sidan, via halvledarkonduktiva till isolerande å andra sidan. Polymererna utgörs av regelbundna kedjor av kolatomer och associeras sålunda till organiska material. Sedan de första vetenskapliga rapporterna publicerades vid slutet av 1970-talet har π-konjugerade polymerer använts och utvecklats i exempelvis solceller, dioder, lysdioder och transistorer. Nobelpriset i kemi tilldelades år 2000 åt Hideki Shirakawa, Alan J. Heeger och Alan G. MacDiarmid för upptäckten och utvecklandet av ledande polymerer. I min avhandling har jag arbetat med att utveckla och förstå lågspännings jonmodulerade organiska transistorer. Två typer av jonmodulerade organiska transistorer studeras: (1) den jonmodulerade organiska fälteffekt transistorn (jonmodulerade OFETen), som utgör den centrala transistorn i avhandlingen, samt (2) den elektrokemiska transistorn. Den första typen fungerar som en konventionell OFET. Strömmen i halvledaren moduleras av det elektriska fältet över isolatorn. Med användandet av en elektrolyt ”isolator” orsakar polariseringen av jonerna däremot ett högt elektriskt fält vid elektrolyt/halvledargränssnittet och man åstadkommer modulering av strömmen redan vid några volts drivspänningar. I den andra typen utnyttjas elektrokemi för att medelst reduktion/oxidation modulera strömmen i den π-konjugerade polymeren. Ett viktigt ändamål i avhandlingen har också varit att kunna tillverka transistorerna med masstillverkningsmetoder. I avhandlingen presenteras de jonmodulerade organiska transistorernas möjlighet att framställas med masstillverkningsmetoder. Nya koncept introduceras och svagheter identifieras. Skillnaderna mellan OFETen, jonmodulerade OFETen och den elektrokemiska transistorn klargörs. Arbetet skall däremot inte anses fullbordat utan forskningen fortgår för att kringgå svagheterna, öka på transistorernas stabilitet och framförallt tillämpa dem i innovativa applikationer.

Molecular modeling of asymmetric induction in heterogeneously catalyzed hydrogenation of the C=O bond

Modifiering av metallytor med starkt adsorberade kirala organiska molekyler är eventuellt den mest relevanta teknik man vet i dag för att skapa kirala ytor. Den kan utnyttjas i katalytisk produktion av enantiomeriskt rena kirala föreningar som behövs t.ex. som läkemedel och aromkemikalier. Trots många fördelar av asymmetrisk heterogen katalys jämfört med andra sätt för att få kirala föreningar, har den ändå inte blivit ett allmänt verktyg för storskaliga tillämpningar. Detta beror t.ex. på brist på djupare kunskaper i katalytiska reaktionsmekanismer och ursprunget för asymmetrisk induktion. I denna studie användes molekylmodelleringstekniker för att studera asymmetriska, heterogena katalytiska system, speciellt hydrering av prokirala karbonylföreningar till motsvarande kirala alkoholer på cinchona-alkaloidmodifierade Pt-katalysatorer. 1-Fenyl-1,2-propandion (PPD) och några andra föreningar, som innehåller en prokiral C=O-grupp, användes som reaktanter. Konformationer av reaktanter och cinchona-alkaloider (som kallas modifierare) samt vätebundna 1:1-komplex mellan dem studerades i gas- och lösningsfas med metoder som baserar sig på vågfunktionsteori och täthetsfunktionalteori (DFT). För beräkningen av protonaffiniteter användes också högst noggranna kombinationsmetoder såsom G2(MP2). Den relativa populationen av modifierarnas konformationer varierade som funktion av modifieraren, dess protonering och lösningsmedlet. Flera reaktant–modifierareinteraktionsgeometrier beaktades. Slutsatserna på riktning av stereoselektivitet baserade sig på den relativa termodynamiska stabiliteten av de diastereomeriska reaktant–modifierare-komplexen samt energierna hos π- och π*-orbitalerna i den reaktiva karbonylgruppen. Adsorption och reaktioner på Pt(111)-ytan betraktades med DFT. Regioselektivitet i hydreringen av PPD och 2,3-hexandion kunde förklaras med molekyl–yta-interaktioner. Storleken och formen av klustret använt för att beskriva Pt-ytan inverkade inte bara på adsorptionsenergierna utan också på de relativa stabiliteterna av olika adsorptionsstrukturer av en molekyl. Populationerna av modifierarnas konformationer i gas- och lösningsfas korrelerade inte med populationerna på Pt-ytan eller med enantioselektiviteten i hydreringen av PPD på Pt–cinchona-katalysatorer. Vissa modifierares konformationer och reaktant–modifierare-interaktionsgeometrier var stabila bara på metallytan. Teoretiskt beräknade potentialenergiprofiler för hydrering av kirala α-hydroxiketoner på Pt implicerade preferens för parvis additionsmekanism för väte och selektiviteter i harmoni med experimenten. De uppnådda resultaten ökar uppfattningen om kirala heterogena katalytiska system och kunde därför utnyttjas i utvecklingen av nya, mera aktiva och selektiva kirala katalysatorer.

Recovery of carboxylic acids from aqueous solutions

Carboxylic acids are commonly used organic acids and have many applications in industries producing food and pharmaceutical products, surfactants and detergents. Especially formic, acetic, propionic and butyric acid are important organic chemicals. These compounds can be found in many side streams and plant effluents. Recovery costs of carboxylic acids are high when they are removed from dilute solution. Conventional processes for the recovery of carboxylic acids from aqueous solutions are classical distillation or extractive distillation, azeotropic distillation or liquid-liquid extraction. The literature part of this Master’s of Science Thesis comprises possible extractants in liquid-liquid extraction of carboxylic acids from aqueous solutions and methods for their regeneration form the extract. The experimental part of this Thesis investigates liquid-liquid extraction of carboxylic acids from aqueous solutions. The aim of this work was to find a suitable extractant for liquid-liquid extraction and suitable process conditions to recover carboxylic acids from aqueous solutions. Also, back extraction of carboxylic acids and their thermal decomposition in relation to distillation of were. Experiments showed that there is more than one possible extractant for liquid-liquid extraction of carboxylic acids. Results also showed that it is possible to separate carboxylic acids and regenerate all the used extractants by vacuum distillation at suitable temperature.

Nematicidal effect of volatile organic compounds (VOCs) on the plant-parasitic nematode Meloidogyne javanica

Previous studies have demonstrated that volatile organic compounds (VOCs), produced by the yeast Saccharomyces cerevisiae, were able to inhibit the development of phytopathogenic fungi. In this context, the nematicidal potential of the synthetic mixture of VOCs, constituted of alcohols and esters, was evaluated for the control of the root-knot nematode Meloidogyne javanica, which causes losses to crops of high economic value. The fumigation of substrate containing second-stage juveniles with VOCs exhibited nematicidal effect higher than 30% for the lowest concentration tested (33.3 µL g-1 substrate), whereas at 66.6 and 133.3 µL g-1 substrate, the nematode mortality was 100%. The present results stimulate other studies on VOCs for nematode management.

Kannettavan kaasuilmaisimen suunnittelu ja toteutus

Työn tarkoituksena on suunnitella ja toteuttaa kannettava kaasuilmaisin, joka soveltuu erityisesti tavallisen kuluttajan tarpeisiin. Kaasuilmaisin on herkkä haihtuville palaville kaasuille, sekä orgaanisille kaasuille. Työssä käytetään Atmelin ATMega164P- mikrokontrolleria, piirin ohjelmointiin käytetään AVR-ISP-II, ja kehitystyökaluina AVRStudio 4:ää. Piirilevy on suunniteltu Cadsoftin Eagle- piirieditorilla. Työssä käydään läpi kokonaisvaltainen sulautetun järjestelmän suunnitteluprosessi, tuotteen spesifikaatioiden määrityksistä aina valmiin fyysisen tuotteen valmistuttamiseen asti. Tuote suunnitellaan Environics Oy:lle.

Enhancing performance of paper coatings by tailor-made plastic pigments

The paper industry is constantly looking for new ideas for improving paper products while competition and raw material prices are increasing. Many paper products are pigment coated. Coating layer is the top layer of paper, thus by modifying coating pigment also the paper itself can be altered and value added to the final product. In this thesis, synthesis of new plastic and hybrid pigments and their performance in paper and paperboard coating is reported. Two types of plastic pigments were studied: core-shell latexes and solid beads of maleimide copolymers. Core-shell latexes with partially crosslinked hydrophilic polymer core of poly(n-butyl acrylate-co-methacrylic acid) and a hard hydrophobic polystyrene shell were prepared to improve the optical properties of coated paper. In addition, the effect of different crosslinkers was analyzed and the best overall performance was achieved by the use of ethylene glycol dimethacrylate (EGDMA). Furthermore, the possibility to modify core-shell latex was investigated by introducing a new polymerizable optical brightening agent, 1-[(4-vinylphenoxy)methyl]-4-(2-henylethylenyl)benzene which gave promising results. The prepared core-shell latex pigments performed smoothly also in pilot coating and printing trials. The results demonstrated that by optimizing polymer composition, the optical and surface properties of coated paper can be significantly enhanced. The optimal reaction conditions were established for thermal imidization of poly(styrene-co-maleimide) (SMI) and poly(octadecene-co-maleimide) (OMI) from respective maleic anhydride copolymer precursors and ammonia in a solvent free process. The obtained aqueous dispersions of nanoparticle copolymers exhibited glass transition temperatures (Tg) between 140-170ºC and particle sizes from 50-230 nm. Furthermore, the maleimide copolymers were evaluated in paperboard coating as additional pigments. The maleimide copolymer nanoparticles were partly imbedded into the porous coating structure and therefore the full potential of optical property enhancement for paperboard was not achieved by this method. The possibility to modify maleimide copolymers was also studied. Modifications were carried out via N-substitution by replacing part of the ammonia in the imidization reaction with amines, such as triacetonediamine (TAD), aspartic acid (ASP) and fluorinated amines (2,2,2- trifluoroethylamine, TFEA and 2,2,3,3,4,4,4-heptafluorobuthylamine, HFBA). The obtained functional nanoparticles varied in size between 50-217 nm and their Tg from 150-180ºC. During the coating process the produced plastic pigments exhibited good runnability. No significant improvements were achieved in light stability with TAD modified copolymers whereas nanoparticles modified with aspartic acid and those containing fluorinated groups showed the desired changes in surface properties of the coated paperboard. Finally, reports on preliminary studies with organic-inorganic hybrids are presented. The hybrids prepared by an in situ polymerization reaction consisted of 30 wt% poly(styrene- co-maleimide) (SMI) and high levels of 70 wt% inorganic components of kaolin and/or alumina trihydrate. Scanning Electron Microscopy (SEM) images and characterization by Fourier Transform Infrared Spcetroscopy (FTIR) and X-Ray Diffraction (XRD) revealed that the hybrids had conventional composite structure and inorganic components were covered with precipitated SMI nanoparticles attached to the surface via hydrogen bonding. In paper coating, the hybrids had a beneficial effect on increasing gloss levels.

Soil organic matter pools in a tropical savanna under agroforestry system in Northeastern Brazil

This study aimed at quantifying total organic carbon stocks and its pools in Acrisol under agroforestry systems with six (AFS6) and thirteen years old (AFS13), slash-and-burn agriculture (SBA) and savanna native forest (SNF) in northeastern Brazil. Soil samples were collected at 0-0.05 m, 0.05-0.10 m, 0.10-0.20 m and 0.20-0.40 m depths in the dry and rainy seasons to evaluate total organic carbon (TOC) stocks and labile carbon (LC), fulvic acid fraction (C-FAF), humic acid fraction (C-HAF), humin (C-HF) and microbial biomass carbon (Cmic) contents. Additionally, carbon management index (CMI) was determined. Higher TOC stocks (97.7 and 81.8 Mg ha-1 for the 0-0.40 m depth in the dry and rainy seasons, respectively) and LC, humic substances and Cmic contents were observed in the AFS13 in all the depths. CMI also was higher in the AFS13 (0-0. 05 m: 158 and 86; 0.05-0.10 m: 171 and 67, respectively for the dry and rainy seasons) especially when compared to the SBA (0-0.05 m: 5.6 and 5.4; 0.05-0.10 m: 5.3 and 5.8, respectively for dry and rainy seasons). The agroforestry systems increased soil quality through the conservation of organic matter and can be considered an excellent strategy to assurance sustainability in tropical soil of Northeastern Brazil

INTERACTIONS OF BIOCHAR AND ORGANIC COMPOUND FOR SEEDLINGS PRODUCTION OF Magonia pubescens A. St.-Hil.

ABSTRACTThe objective of this study was to test the hypothesis that biochar, applied with cattle manure, promotes better development of seedlings of Magonia pubescens St. Hil. The experiment was conducted at the State University of Mato Grosso, Nova Xavantina, Brazil, in 2011. We used a completely randomized design, with twelve treatments and three replications. The substrates formed by the higher levels of cattle manure plus biochar (30%) provided better results of height, diameter and aerial biomass. However, the Dickson Quality Index has not confirmed the quality of seedlings in these treatments. We also observed that the doses of biochar (20 and 30%) when added separately to the Latosol, are not efficient for the growth improvement of the seedlings. Based on the present results, we validate the hypothesis that substrates formed with a mixture of cattle manure and biochar are effective to improve the production of seedlings of M. pubescens.

SOIL ORGANIC CARBON, CARBON STOCK AND THEIR RELATIONSHIPS TO PHYSICAL ATTRIBUTES UNDER FOREST SOILS IN CENTRAL AMAZONIA

ABSTRACT The soil carbon under Amazonian forests has an important roles in global changing, making information on the soil content and depths of these stocks are considerable interest in efforts to quantify soil carbon emissions to the atmosphere.This study quantified the content and soil organic carbon stock under primary forest up to 2 m depth, at different topographic positions, at Cuieiras Biological Reserve, Manaus/ ZF2, km 34, in the Central Amazon, evaluating the soil attributes that may influence the permanence of soil carbon. Soil samples were collected along a transect of 850 m on topographic gradient Oxisol (plateau), Ultisol (slope) and Spodosol (valley). The stocks of soil carbon were obtained by multiplying the carbon content, soil bulk density and trickiness of soil layers. The watershed was delimited by using STRM and IKONOS images and the carbon contend obtained in the transects was extrapolated as a way to evaluate the potential for carbon stocks in an area of 2678.68 ha. The total SOC was greater in Oxisol followed by Spodosol and Ultisol. It was found direct correlations between the SOC and soil physical attributes. Among the clay soils (Oxisol and Ultisol), the largest stocks of carbon were observed in Oxisol at both the transect (90 to 175.5 Mg C ha-1) as the level of watershed (100.2 to 195.2 Mg C ha-1). The carbon stocks under sandy soil (Spodosol) was greater to clay soils along the transect (160-241 Mg C ha-1) and near them in the Watershed (96.90 to 146.01 Mg C ha-1).

Removal of organic matter and nutrients from slaughterhouse wastewater by using Eichhornia crassipes and evaluation of the generated biomass composting

The objective of this research was to evaluate the performance of the aquatic macrophyte Eichhornia crassipes applied in situ in a slaughter house treatment system, located in the west of the Paraná state, Brazil, regarding the nutrients removal and organic matter. Moreover, it aimed to obtain data from the production, management and composting practices of the biomass generated in the system. During 11 months of macrophytes development, physic and chemical parameters were monitored and plant density was controlled by periodical removal of excess biomass, which was weekly monitored and it is expressed in kg of aquatic plant per m² covered area. The degradation of the macrophytes removed from the treatment system was evaluated at the pilot scale in eight composting piles of 0.60 m³ that underwent four different treatments and two repetitions: T1 - water hyacinth (Eichhornia crassipes); T2 - water hyacinth and swine excrement (7:1), T3 - water hyacinth, swine excrement and earth (7:1:0,67), and T4 - water hyacinth, swine excrement and cellulosic gut (7:1:0,67), for a period of 90 days. The results indicated maximum removal efficiencies of 77.2% for COD; 77.8% for BOD, 87.9% for total nitrogen, 47.5% for ammonia nitrogen and 38.9% for total phosphorus for a five-day retention time. For biomass stabilization by composting, considering the C:N ratio as an indicator of compost maturity, it was observed that treatment T4 resulted in the shortest stabilization period (60 days). No difference was verified in the biostabilization rates at 5% level by the F test.

Recycling of nutrients with application of organic waste in degraded pasture

The utilization of organic wastes represents an alternative to recover degraded pasture. The experiment aimed to assess the changes caused by the provision of different organic waste (poultry litter, turkey litter and pig manure) in a medium-textured Oxisol in Brazilian Savanna under degraded pasture. It was applied different doses of waste compared to the use of mineral fertilizers and organic mineral and evaluated the effect on soil parameters (pH, organic matter, phosphorus and potassium) and leaf of Brachiariadecumbens (crude protein, phosphorus and dry mass production). It was observed that application of organic waste did not increase the level of soil organic matter and pH in the surface layer, and the application of turkey litter caused acidification at depths of 0.20-0.40 m and 0.40-0.60 m. There was an increase in P and K in the soil with the application of poultry litter and swine manure. All organic wastes increased the productivity of dry matter and crude protein and phosphorus. The recycling of nutrients via the application of organic waste allows efficiency of most parameters similar to those observed with the use of mineral sources, contributing to improving the nutritional status of soil-plantsystem.

Evapotranspiration and crop coefficient for potato in organic farming

The aim of this study was to quantify the water consumption and the crop coefficients (Kc) for the potato (Solanum tuberosum L.), in Seropédica, Rio de Janeiro (RJ), Brazil, under organic management, and to simulate the crop evapotranspiration (ETc) using the Kc obtained in the field and the ones recommended by the Food and Agriculture Organization (FAO). The water consumption was obtained through soil water balance, using TDR probes installed at 0.15m and 0.30m deep. At the different stages of development, the Kc was determined by the ratio of ETc and reference evapotranspiration, obtained by Penman-Monteith FAO 56. The crop coefficients obtained were 0.35, 0.45, 1.29 and 0.63. The accumulated ETc obtained in the field was 109.6 mm, while the ETc accumulated from FAO's Kc were 142.2 and 138mm, respectively, considering the classical values and the values adjusted to the local climatic conditions. The simulation of water consumption based on meteorological data of historical series from 1961 to 2007 provided higher value of ETc when compared with the one obtained in the field. From the meteorological data of historical series, it was observed that the use of Kc recommended by FAO may overestimate the amount of irrigation water by 9%, over the same growing season.

Evaluation of the effect of the seed extract of Moringa oleifera Lam over the efficiency of organic filters in wastewater treatment of dairy cattle breeding

This study aimed to evaluate the effect of Moringa oleifera Lam extract on the removal of total solids (TS), total suspended solids (TSS) and chemical oxygen demand (COD), in different filter media for treating wastewater of dairy cattle breeding (DCW). The moringa seed extract was obtained by grinding 50 g of seeds in one liter of distilled water and, after passing the solution through a quantitative paper filter of 25 microns, 60 mL of the extract were added to wastewater from cattle breeding before the filtration process in organic filters made of thin coal, bamboo leaves, eucalyptus leaves, gliricidia branches and sawdust. This was followed by the completely randomized experimental design, adopting a factorial of 5 x 2. Aliquots of filtered effluent were collected and the total solids (TS) concentrations, total suspended solids (TSS) and chemical oxygen demand (COD) were determined. It was found that the increase in the efficiency of removal of COD and total solids can be attributed to the coagulating power of the moringa seed extract, wherein the filter medium with bamboo leaves presented the best performance, showing potential for use as alternative filter material in the primary treatment of DCW.

Performance of an anaerobic-aerobic reactor and kinetic study of organic matter removal of cattle slaughterhouse effluent

This paper sought to evaluate the behavior of an upflow Anaerobic-Aerobic Fixed Bed Reactor (AAFBR) in the treatment of cattle slaughterhouse effluent and determine apparent kinetic constants of the organic matter removal. The AAFBR was operated with no recirculation (Phase I) and with 50% of effluent recirculation (Phase II), with θ of 11h and 8h. In terms of pH, bicarbonate alkalinity and volatile acids, the results indicated the reactor ability to maintain favorable conditions for the biological processes involved in the organic matter removal in both operational phases. The average removal efficiencies of organic matter along the reactor height, expressed in terms of raw COD, were 49% and 68% in Phase I and 54% and 86% in Phase II for θ of 11h and 8h, respectively. The results of the filtered COD indicated removal efficiency of 52% and k = 0.0857h-1 to θ of 11h and 42% and k = 0.0880h-1 to θ of 8h in the Phase I. In Phase II, the removal efficiencies were 59% and 51% to θ of 11h and 8h, with k = 0.1238h-1 and k = 0.1075 h-1, respectively. The first order kinetic model showed good adjustment and described adequately the kinetics of organic matter removal for θ of 11h, with r² equal to 0.9734 and 0.9591 to the Phases I and II, respectively.

Printed low-voltage organic transistors on plastics and paper

The main advantage of organic electronics over the more widespread inorganic counterparts lies not in the electrical performance, but rather in the solution processability that opens up for low-cost flexible electronics (e.g. displays, sensors and smart tags) fabricated by using printing techniques. Replacing the commonly used laboratory-scale fabrication techniques with mass-printing techniques is, however, truly challenging, especially when low-voltage operation is required. In this thesis it is, nevertheless, demonstrated that low-voltage organic transistors can be fully printed with a similar performance to that of transistors made by laboratory scale techniques. The use of an ion-modulated type of organic field effect transistor (OFET) not only enabled low-voltage operation and printability, but was also found to result in low sensitivity to the surface roughness of the substrate. This allows not only the use of low-cost plastic substrates, but even the use of paper as a substrate. However, while absorption into the porous paper surface is advantageous in a graphical printing process, by reducing the spreading and the coffee-stain effect and by improving the adhesion, it provides great challenges when applying thin electrically active layers. In spite of these difficulties we were able to demonstrate the first low-voltage OFET to be fabricated on paper. We have also shown that low-cost incandescent lamps can be used for sintering printed metal-nanoparticles, and that the process was especially suitable on paper and compatible with a roll-to-roll manufacturing process.