Effects of Surface Properties and Wood Modification into Direct Printing on Wood

Building industry is a high volume branch which could provide prominent markets for wood based interior decoration solutions. Competition in interior decoration markets requires versatility in appearance. Versatility in wood appearance and added value could be achieved by printing grain patterns of different species or images directly onto wood. The problem when planning wood printing’s implementing into durable applications is basically how to transfer a high quality image or print sustainably onto wood, which is porous, heterogeneous, dimensionally unstable, non-white and rough. Wood preservation or treating, and modification can provide durability against degradation but also effect to the surface properties of wood which will effect on printability. Optimal adhesion is essential into print quality, as too high ink absorbance can cause spreading and too low ink absorbance cause pale prints. Different printing techniques have different requirements on materials and production. The direct printing on wood means, that intermedias are not used. Printing techniques with flexible printing plates or in fact non-impact techniques provide the best basis for wood printing. Inkjet printing of wood with different mechanical or chemical surface treatments, and wood plastic composite material gave good results that encourage further studies of the subject. Sanding the wood surface anti-parallel to the grain gave the best overall printing quality. Spreading parallel to the grain could not be avoided totally, except in cases where wood was treated hydrophobic so adhesion of the ink was not sufficient. Grain pattern of the underlying wood stays clearly visible in the printed images. Further studies should be made to fine tune the methods that already gave good results. Also effects of moisture content of wood, different inks, and long-term exposure to UV-radiation should be tested.

Determinação voltamétrica de metais em águas e fluidos biológicos empregando mineralização de amostras com radiação ultravioleta

This work describes the optimization of pretreatment steps for the destruction of organic matter in samples of waters and biological fluids, by using an UV irradiation system with a high power UV radiation source (400 W). The efficiency of the system constructed for the photo-decomposition of samples of model waters, natural waters and biological fluids was investigated by performing recovery experiments of the metallic species Zn(II), Cd(II), Pb(II), Cu(II), Al(III) and Fe(III). The use of UV irradiation allowed the liberation of metals bound to the organic matrix and the determination of the total content of elements in the samples.

Efeito do intemperismo artificial em quatro madeiras tropicais monitorado por espectroscopia de infravermelho (DRIFT)

Four tropical woods, were investigated to compare their performance and natural resistances to artificial weathering using the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). The species were garapeira (Apuleia leiocarpa), itaúba (Mezilaurus itauba) and tauari (Couratari sp.), woods traditionally indicated for exterior uses, and marupá (Simarouba amara), that served as reference. The samples were submitted to cycles of UV radiation (350 nm) and water until 2,000 h. The photodegradation processes of woods surfaces were accomplished monitoring the changes in the intensities associated to lignin (1508 cm-1) and carbonyl group (1736 cm-1) absorptions. The results have shown that lignin was the first component to be photodegradated, resulting in surfaces mainly composed by cellulose, after 2,000 h of UV irradiation. The processes of formation and lixiviation of carbonyl compounds were different for each species. The experimental conditions used in this work were too severe to evaluate the wood density and extractives content influences during the treatment.

Síntese, caracterização e atividade fotocatalítica de catalisadores nanoestruturados de TiO2 dopados com metais

Titanium dioxide nanostructured catalysts (nanotubes) doped with different metals (silver, gold, copper, palladium and zinc) were synthesized by the hydrothermal method in order to promote an increase in their photocatalytic activity under visible light. The catalysts were characterized by X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy and specific area and pore volume determination. The materials' photocatalytic activity was evaluated by rhodamine B decomposition in a glass batch reactor. Under UV radiation, only nanotubes doped with palladium were more active than the TiO2 P25, but the samples doped with silver, palladium and gold exhibited better results than the undoped samples under visible light.

Aplicação da radiação ultravioleta como forma de contribuição para a química verde e construção de um reator fotoquímico alternativo e de baixo custo, para pré-tratamento de amostras

Ultraviolet radiation corresponds to a fraction of electromagnetic radiation, covering wavelengths between 1 and 400 nm. Methods based on UV irradiation have become popular because it is possible to treat samples simply by applying energy, avoiding procedures that require the use of toxic substances, thus contributing to the development of Green Chemistry. This study aimed to assess the main applications of UV radiation reported in the literature and thoroughly described the construction of an alternative and low-cost photochemical reactor to be used for the pretreatment of samples in the laboratory. The use of this new photochemical reactor in the clean-up of milk samples for spectrofluorimetric measurements was also reported.

Altistuminen PAH-yhdisteille kreosoottikyllästetyn puun käsittelyssä

Tässä työssä selvitettiin altistutaanko kreosoottikyllästetyn puun käsittelyssä polysyklisille aromaattisille hiilivedyille ja mistä työsuojelullisista syistä altistumista tapahtuu. Lisäksi työssä selvitettiin mitä altistuminen tarkoittaa työnantajan kannalta. Altistumista tarkasteltiin työturvallisuuden näkökulmasta. Lähtöaineisto koostui maastossa toteutetuista tutkimuksista. Aineisto kerättiin kesällä 2009 kolmesta Itä-Suomessa sijaitsevasta kohteesta, joissa käsiteltiin kreosootilla kyllästettyä puuta. Altistumisen todentamiseksi tutkimukseen osallistuneilta työntekijöiltä pyydettiin virtsanäytteet, joista analysoitiin yhden yleisimmän PAH-altistumista indikoivan merkkiaineen, virtsan 1-pyrenolin pitoisuuksia työntekijöillä. Altistumisen syiden selvittämiseksi työntekijöitä haastateltiin ja havainnoitiin. Tulosten perusteella työntekijät altistuvat PAH-yhdisteille työssään. PAH-altistumisen merkkiaineena olleelle virtsan 1-pyrenolille ei toimenpiderajaa tällä hetkellä ole, mutta se on Työterveyslaitoksella suunnitteilla. Lainsäädäntö velvoittaa erinäisin toimenpitein työnantajaa minimoimaan työntekijöiden altistumisen syöpäsairauden vaaraa aiheuttaville aineille, kuten PAH-yhdisteille. Tulosten perusteella työsuojelutoimenpiteitä on syytä tehostaa altistumisen minimoimiseksi ja etenkin ihon suojaamiseen on syytä kiinnittää erityistä huomiota.

Pretreatment in membrane filtration of wood hydrolysate

Interest in recovery of valuable components from process streams has increased in recent years. Purpose of biorefinery is to utilize components that otherwise would go to waste. Hemicelluloses, for example, could be utilized in production of many valuable products. One possible way to separate and fractionate hemicelluloses is membrane filtration. In the literature part of this work membrane fouling in filtration processes of pulp and paper process- and wastewaters was investigated. Especially purpose was to find out the possible fouling compounds, after which facilities to remove or modify such components less harmful were studied. In the experimental part different pretreatment methods, mainly to remove or degrade lignin from wood hydrolysate, were studied. In addition, concentration of hemicelluloses and separation from lignin were examined with two ultrafiltration membranes; UFX5 and RC70PP. Changes in feed solution, filtration capacity and fouling of membranes were used to evaluate the effects of pretreatment methods. Changes in hydrolysate composition were observed with different analysis methods. Filtration of hydrolysate proved to be challenging, especially with the UFX5 membrane. The more hydrophilic RC70PP membrane did not seem to be fouled as severely as the UFX5 membrane, according to pure water flux measurements. The UFX5 membrane retained hemicelluloses rather well, but problems arose from rapid flux decline resulting from concentration polarization and fouling of membrane. Most effective pretreatment methods in the case with the UFX5 membrane proved to be prefiltration with the RC70PP membrane, activated carbon adsorption and photocatalytic oxidation using titanium dioxide and UV radiation. An additional experiment with PHW extract showed that pulsed corona discharge treatment degraded lignin quite efficiently and thus improved filtration capacity remarkably, even over six times compared to the filtration with untreated extract.

Chiral separations of mandelic acid by HPLC using molecularly imprinted polymers

Styrene is used in a variety of chemical industries. Environmental and occupational exposures to styrene occur predominantly through inhalation. The major metabolite of styrene is present in two enantiomeric forms, chiral R- and S- hydroxy-1-phenyl-acetic acid (R-and S-mandelic acid, MA). Thus, the concentration of MA, particularly of its enantiomers, has been used in urine tests to determine whether workers have been exposed to styrene. This study describes a method of analyzing mandelic acid using molecular imprinting techniques and HPLC detection to perform the separation of diastereoisomers of mandelic acid. The molecularly imprinted polymer (MIP) was prepared by non-covalent molecular imprinting using (+) MA, (-) MA or (+) phenylalanine, (-) phenylalanine as templates. Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were copolymerized in the presence of the template molecules. The bulk polymerization was carried out at 4ºC under UV radiation. The resulting MIP was grounded into 25~44¼m particles, which were slurry packed into analytical columns. After the template molecules were removed, the MIP-packed columns were found to be effective for the chromatographic resolution of (±)-mandelic acid. This method is simpler and more convenient than other chromatographic methods.

Swine manure post-treatment technologies for pathogenic organism inactivation

Swine manure agricultural use is a common practice in Brazil. Their physic-chemical characteristics favor its use as biofertilizer, but the presence of pathogens may become a risk to human health. This research presents a qualitative study of the main alternatives of pig manure disinfection, analyzing efficiency, advantages and limitations of each procedure. The disinfection studies reported in literature are based on the following treatments: alkaline, thermal, biological, chemical, and physical. The greater efficiencies are in thermal treatment (> 4 log: 60 °C), chemical treatment (3 to 4 log: 30mg Cl- L-1; 3 to 4 log: 40 mg O3 L-1) and physical treatment (3 a 4 log: 220 mJ UV radiation cm-2). The biological treatment (anaerobiosis) also promotes the pathogen reduction of swine manure, however with lower efficiency (1 to 2 log). The selection of the treatment should consider: implementation and operation cost, necessity of preliminary treatment, efficiency obtained and destination of the treated manure (agricultural use, water reuse). Brazilian regulation does not have specific guidelines for the microbiological quality of animal production effluents that is very important to be considered due to confined animal feeding operation transformation in the last years in the country.

The Role of Oxidative Stress in Environmental Responses of Fennoscandian Animals

All aerobic organisms have to deal with the toxicity of oxygen. Oxygen enables more efficient energy production compared to anaerobic respiration or fermentation, but at the same time reactive oxygen species (ROS) are being formed. ROS can also be produced by external factors such as UV-radiation and contamination. ROS can cause damage to biomolecules such as DNA, lipids and proteins and organisms try to keep the damage as small as possible by repairing biomolecules and metabolizing ROS. All ROS are not harmful, because they are used as signaling molecules. To cope against ROS organism have an antioxidant (AOX) system which consists both enzymatic and non-enzymatic AOX defense. Some AOX are produced by the organism itself and some are gained via diet. In this thesis I studied environmentally caused changes in the redox regulation of different wild vertebrate animals to gain knowledge on the temporal, spatial and pollution-derived-effects on the AOX systems. As study species I used barn swallow, ringed seal and the Baltic salmon. For the barn swallow the main interest was the seasonal fluctuation in the redox regulation and its connection to migration and breeding. The more contaminated ringed seals of the Baltic Sea were compared to seals from cleaner Svalbard to investigate whether they suffered from contaminant induced oxidative stress. The regional and temporal variation in redox regulation and regional variation in mRNA and protein expressions of Baltic salmon were studied to gain knowledge if the salmon from different areas are equally stressed. As a comparative aspect the redox responses of these different species were investigated to see which parts of the AOX system are substantial in which species. Certain parts of AOX system were connected to breeding and others to migration in barn swallows, there was also differences in biotransformation between birds caught from Africa and Finland. The Baltic ringed seal did not differ much from the seals from Svalbard, despite the difference in contaminant load. A possible explanation to this could be the enhanced AOX mechanisms against dive-associated oxidative stress in diving air-breathing animals, which also helps to cope with ROS derived from other sourses. The Baltic salmon from Gulf of Finland (GoF) showed higher activities in their AOX defense enzymes and more oxidative damage than fish from other areas. Also on mRNA and proteomic level, stress related metabolic changes were most profound in in the fish from GoF. Mainly my findings on species related differences followed the pattern of mammals showing highest activities and least damage and birds showing lower activities and most damage, fish being intermediate. In general, the glutathione recycling-related enzymes and the ratio of oxidized and reduced glutathione seemed to be the most affected parameters in all of the species.

NIR-Vis Up-Conversion Luminescence in the Yb3+,Er3+ Doped Y2O2S, ZrO2, and NaYF4 Nanomaterials

Since the discovery of the up-conversion phenomenon, there has been an ever increasing interest in up-converting phosphors in which the absorption of two or more low energy photons is followed by emission of a higher energy photon. Most up-conversion luminescence materials operate by using a combination of a trivalent rare earth (lanthanide) sensitizer (e.g. Yb or Er) and an activator (e.g. Er, Ho, Tm or Pr) ion in a crystal lattice. Up-converting phosphors have a variety of potential applications as lasers and displays as well as inks for security printing (e.g. bank notes and bonds). One of the most sophisticated applications of lanthanide up-conversion luminescence is probably in medical diagnostics. However, there are some major problems in the use of photoluminescence based on the direct UV excitation in immunoassays. Human blood absorbs strongly UV radiation as well as the emission of the phosphor in the visible. A promising way to overcome the problems arising from the blood absorption is to use a long wavelength excitation and benefit from the up-conversion luminescence. Since there is practically no absorption by the whole-blood in the near IR region, it has no capability for up-conversion in the excitation wavelength region of the conventional up-converting phosphor based on the Yb3+ (sensitizer) and Er3+ (activator) combination. The aim of this work was to prepare nanocrystalline materials with high red (and green) up-conversion luminescence efficiency for use in quantitative whole-blood immunoassays. For coupling to biological compounds, nanometer-sized (crystallite size below 50 nm) up-converting phosphor particles are required. The nanocrystalline ZrO2:Yb3+,Er3+, Y2O2S:Yb3+,Er3+, NaYF4:Yb3+,Er3+ and NaRF4-NaR’F4 (R: Y, Yb, Er) materials, prepared with the combustion, sol-gel, flux, co-precipitation and solvothermal synthesis, were studied using the thermal analysis, FT-IR spectroscopy, transmission electron microscopy, EDX spectroscopy, XANES/EXAFS measurements, absorption spectroscopy, X-ray powder diffraction, as well as up-conversion and thermoluminescence spectroscopies. The effect of the impurities of the phosphors, crystallite size, as well as the crystal structure on the up-conversion luminescence intensity was analyzed. Finally, a new phenomenon, persistent up-conversion luminescence was introduced and discussed. For efficient use in bioassays, more work is needed to yield nanomaterials with smaller and more uniform crystallite sizes. Surface modifications need to be studied to improve the dispersion in water. On the other hand, further work must be carried out to optimize the persistent up-conversion luminescence of the nanomaterials to allow for their use as efficient immunoassay nanomaterials combining the advantages of both up-conversion and persistent luminescence.

Déficience dans la réparation par excision de nucléotides en phase S induite par la séquestration du facteur de réplication RPA

Introduction Les lésions induites par les rayons UV peuvent causer des blocages dans la réplication de l'ADN. Ces dommages sont éliminés par le processus moléculaire très conservé de réparation par excision de nucléotides (NER). Nous avons précédemment démontré que la protéine ATR, une kinase majeure impliquée dans le stress réplicatif, est requise pour une NER efficace, et ce exclusivement durant la phase S. Des résultats subséquents ont suggéré que ce prérequis n’était pas lié à la réponse induite par ATR, mais plutôt d’une conséquence globale causée par la présence de stress réplicatif. En ce sens, nous mettons l’emphase qu’après irradiation UV, le complexe RPA joue un rôle crucial dans l'activation des mécanismes de NER ainsi que dans le redémarrage des fourches de réplication bloquées. Hypothèses: En général, les mutations qui confèrent une augmentation du stress réplicatif engendrent une séquestration excessive du facteur RPA aux fourches de réplication bloquées ce qui réduit son accessibilité pour le NER. Méthodes et résultats: Le modèle de la levure a été choisi pour vérifier cette hypothèse. Nous avons développé un essai de NER spécifique à chacune des phases du cycle cellulaire pour démontrer que les cellules déficientes en Mec1, l’homologue d’ATR, sont défectives dans la réparation par excision de nucléotides spécifiquement en phase S. De plus, plusieurs autres mutants de levure, caractérisés par un niveau de dommages spontanés élevé, ont aussi exhibé un défaut similaire. Ces mutants ont démontré une fréquence et une intensité de formation de foyers de RPA plus élevée. Finalement, une diminution partielle de RPA dans les levures a induit un défaut significatif dans le NER spécifiquement durant la phase S. Conclusion: Nos résultats supportent la notion que la séquestration de RPA aux fourches de réplication endommagées durant la phase S prévient son utilisation pour la réparation par excision de nucléotides ce qui inhibe fortement l'efficacité de réparation. Cette étude chez la levure facilite l’élucidation du phénomène analogue chez l’humain et, ultimement, comprend des implications majeures dans la compréhension du mécanisme de développement des cancers UV-dépendants.

Photodegradation of Methylorange over Zirconia Doped TiO2 Using Solar Energy

The heterogeneous photocatalytic degradation of methylorange over TiO2 is studied and is found to be cost effective. Effect of Zirconium metal incorporation over titania system is investigated. Photocatalytic degradation of methylorange using solar radiation is found to be highly economical when compared with the processes using artificial UV radiation, which require substantial electrical power input. The characterization of titania as well as modified zirconium metal doped titania systems are done using XRD, FTIR and EDAX measurements. The catalytic activities of different systems are also compared and is tried to correlate with the crystallite size and presence of dopant metal.

Synthesis and Photoluminescence Properties of Novel Red Phosphors for White Light Emitting Diode Applications

Several series of Eu3+ based red emitting phosphor materials were synthesized using solid state reaction route and their properties were characterized. The present studies primarily investigated the photoluminescence properties of Eu3+ in a family of closely related host structure with a general formula Ln3MO7. The results presented in the previous chapters throws light to a basic understanding of the structure, phase formation and the photoluminescence properties of these compounds and their co-relations. The variation in the Eu3+ luminescence properties with different M cations was studied in Gd3-xMO7 (M = Nb, Sb, Ta) system.More ordering in the host lattice and more uniform distribution of Eu3+ ions resulting in the increased emission properties were observed in tantalate system.Influence of various lanthanide ion (Lu, Y, Gd, La) substitutions on the Eu3+ photoluminescence properties in Ln3MO7 host structures was also studied. The difference in emission profiles with different Ln ions demonstrated the influence of long range ordering, coordination of cations and ligand polarizability in the emission probabilities, intensity and quantum efficiency of these phosphor materials. Better luminescence of almost equally competing intensities from all the 4f transitions of Eu3+ was noticed for La3TaO7 system. Photoluminescence properties were further improved in La3TaO7 : Eu3+ phosphors by the incorporation of Ba2+ ions in La3+ site. New red phosphor materials Gd2-xGaTaO7 : xEu3+ exhibiting intense red emissions under UV excitation were prepared. Optimum doping level of Eu3+ in these different host lattices were experimentally determined. Some of the prepared samples exhibited higher emission intensities than the standard Y2O3 : Eu3+ red phosphors. In the present studies, Eu3+ acts as a structural probe determining the coordination and symmetry of the atoms in the host lattice. Results from the photoluminescence studies combined with the powder XRD and Raman spectroscopy investigations helped in the determination of the correct crystal structures and phase formation of the prepared compounds. Thus the controversy regarding the space groups of these compounds could be solved to a great extent. The variation in the space groups with different cation substitutions were discussed. There was only limited understanding regarding the various influential parameters of the photoluminescence properties of phosphor materials. From the given studies, the dependence of photoluminescence properties on the crystal structure and ordering of the host lattice, site symmetries, polarizability of the ions, distortions around the activator ion, uniformity in the activator distribution, concentration of the activator ion etc. were explained. Although the presented work does not directly evidence any application, the materials developed in the studies can be used for lighting applications together with other components for LED lighting. All the prepared samples were well excitable under near UV radiation. La3TaO7 : 0.15Eu3+ phosphor with high efficiency and intense orange red emissions can be used as a potential red component for the realization of white light with better color rendering properties. Gd2GaTaO7 : Eu3+, Bi2+ red phosphors give good color purity matching to NTSC standards of red. Some of these compounds exhibited higher emission intensities than the standard Y2O3 : Eu3+ red phosphors. However thermal stability and electrical output using these compounds should be studied further before applications. Based on the studies in the closely related Ln3MO7 structures, some ideas on selecting better host lattice for improved luminescence properties could be drawn. Analyzing the CTB position and the number of emission splits, a general understanding on the doping sites can be obtained. These results could be helpful for phosphor designs in other host systems also, for enhanced emission intensity and efficiency.

Solar influences on dynamical coupling between the stratosphere and troposphere

We use a simplified atmospheric general circulation model (AGCM) to investigate the response of the lower atmosphere to thermal perturbations in the lower stratosphere. The results show that generic heating of the lower stratosphere tends to weaken the sub-tropical jets and the tropospheric mean meridional circulations. The positions of the jets, and the extent of the Hadley cells, respond to the distribution of the stratospheric heating, with low latitude heating displacing them poleward, and uniform heating displacing them equatorward. The patterns of response to the low latitude heating are similar to those found to be associated with solar variability in previous observational data analysis, and to the effects of varying solar UV radiation in sophisticated AGCMs. In order to investigate the chain of causality involved in converting the stratospheric thermal forcing to a tropospheric climate signal we conduct an experiment which uses an ensemble of model spin-ups to analyse the time development of the response to an applied stratospheric perturbation. We find that the initial effect of the change in static stability at the tropopause is to reduce the eddy momentum flux convergence in this region. This is followed by a vertical transfer of the momentum forcing anomaly by an anomalous mean circulation to the surface, where it is partly balanced by surface stress anomalies. The unbalanced part drives the evolution of the vertically integrated zonal flow. We conclude that solar heating of the stratosphere may produce changes in the circulation of the troposphere even without any direct forcing below the tropopause. We suggest that the impact of the stratospheric changes on wave propagation is key to the mechanisms involved.