Rasvasuodatus UV-valon avulla

Tämä kandidaatintyö käsittelee rasva-aerosolien vähentämistä liesituulettimissa ultraviolettivalon (UV) ja titaanioksidin avulla (TiO2). Työssä käsitellään rasva-aerosolien aiheuttamia haittoja julkisissa keittiöissä ja liesituulettimen merkitystä rasva-aerosolipitoisuuksiin. Työn tavoitteena on selvittää, miten rasva-aerosolit käyttäytyvät kun niitä suodatetaan UV-valon ja TiO2-katalyytin avulla. Työssä myös pohditaan onko UV/TiO2-menetelmä tehokas liesituulettimen rasvan vähentäjä.

Estimation of aircraft aerodynamic derivatives using Extended Kalman Filter

Design of flight control laws, verification of performance predictions, and the implementation of flight simulations are tasks that require a mathematical model of the aircraft dynamics. The dynamical models are characterized by coefficients (aerodynamic derivatives) whose values must be determined from flight tests. This work outlines the use of the Extended Kalman Filter (EKF) in obtaining the aerodynamic derivatives of an aircraft. The EKF shows several advantages over the more traditional least-square method (LS). Among these the most important are: there are no restrictions on linearity or in the form which the parameters appears in the mathematical model describing the system, and it is not required that these parameters be time invariant. The EKF uses the statistical properties of the process and the observation noise, to produce estimates based on the mean square error of the estimates themselves. Differently, the LS minimizes a cost function based on the plant output behavior. Results for the estimation of some longitudinal aerodynamic derivatives from simulated data are presented.

UV-LED -lamppujen soveltuminen laivojen painolastivesien käsittelyyn

Painolastivesien mukana kulkeutuvien lajien leviäminen on yksi vakavimmista globaaleista ympäristöuhkista. Kansainvälinen merenkulkujärjestö IMO määritteli vuonna 2004 kansainvälisen painolastivesiyleissopimuksen, jonka tarkoituksena on ehkäistä laivojen painolastivesien mukana kulkeutuvien lajien leviämistä. Sopimus velvoittaa aluksia käsittelemään niiden painolastivedet ja se sisältää myös käsittelyjärjestelmiltä edellytetyt vaatimukset. Vaikka sopimus ei ole vielä astunut voimaan, painolastivesien käsittelyyn löytyy markkinoilta jo useita kymmeniä IMO:n hyväksymiä käsittelyjärjestelmiä, jotka hyödyntävät erilaisia mekaanisia, fysikaalisia ja kemiallisia menetelmiä. Yksi yleisimmin käytetyistä menetelmistä on UV-säteilytys. UV-säteily tuotetaan elohopealampuilla, jotka kuitenkin kuluttavat paljon energiaa ja sisältävät myrkyllistä elohopeaa. Tämän työn tarkoituksena oli selvittää, voisiko elohopealamput korvata lähitulevaisuudessa UV-LED -lampuilla. UV-LED –lamppujen etuja ovat muun muassa energiatehokkuus, kestävä rakenne ja myrkyttömyys. Työn tärkeimpänä tavoitteena oli tutkia laboratoriomittausten avulla, millainen UV-annosmäärä 10-50 µm kokoisten kasviplanktonien inaktivoimiseen tarvitaan. Mittausjärjestelyt vastasivat suurelta osin IMO:n vaatimuksia. Laboratoriomittauksissa käytettiin 265 nm:n aallonpituudella toimivia UV-LED -lamppuja. Näytteiden analysoinnissa käytettiin sekä PAM-fluorometriä että virtaussytometriä. Saatujen tulosten perusteella tutkimuksessa käytettyjen lajien Asterionellopsis glacialis ja Thalassiosira sp. täydelliseen inaktivoitumiseen tarvittiin noin 600 mJ/cm2 suuruinen UV-annos. Tulos vastasi ennakko-odotuksia ja se oli vertailukelpoinen muiden aiheesta tehtyjen tutkimusten kanssa. Koska nykyisten UV-LED –lamppujen teho on hyvin alhainen, ne eivät vielä sovellu painolastivesien käsittelyyn. UV-LED –lamppujen kehitystyö on kuitenkin käynnissä ja on arvioitu, että niitä voitaisiin käyttää suurten virtaamien käsittelyssä 5-10 vuoden kuluttua.

Veden desinfiointi UV-LED-valolla

Veden riittämätön puhdistus aiheuttaa riskin veden käyttäjille. Miljoonia kuolemia vuosittain aiheuttavien vesiteitse leviävien sairauksien ehkäisemiseksi vaaditaan tehokkaita juomaveden desinfiointimenetelmiä. Kuivuuden ja väestönkasvun myötä veden tarve on lisääntynyt ja vedenkulutus tulee yhä kasvamaan. Tästä syystä mahdollisuus kierrättää vettä hyödyntäen sitä esimerkiksi kasteluun on saanut yhä enemmän huomiota. Kierrätettävä vesi on kuitenkin käsiteltävä huolellisesti sen sisältämän mikrobiologisen kontaminaatioriskin vuoksi. Ultraviolettisäteily luokitellaan fysikaaliseksi desinfiointimenetelmäksi. Sen tehokkuus perustuu mikro-organismien absorboimaan UV-säteilyyn, jonka aiheuttamien DNA:ssa tai RNA:ssa tapahtuvien muutoksien seurauksena mikro-organismi inaktivoituu ja estyy lisääntymästä. UV-desinfioinnissa on tyypillisesti käytetty elohopeahöyrylamppuja. Vaihtoehtoinen UV-säteilyn lähde ovat LEDit eli valoa emittoivat diodit. Matalapaine-elohopeahöyrylamppujen emittoima säteily on aallonpituudella 254 nm ja keskipaine-elohopeahöyrylamppujen emittoima säteily on laajakaistaista säteilyä. Energiatehokkuuden lisäksi LEDien etuna on, että niillä voidaan tuottaa kapeakaista säteilyä aallonpituudella, joka parhaiten absorboituu DNA:han. Tämän diplomityön tarkoituksena oli tutkia, onko UVC-alueen aallonpituuksien yhdistelmillä synergistisiä etuja LEDien desinfiointitehokkuuteen, kun desinfioidaan virtaavaa vettä useilla säteilyannoksilla ja indikaattorimikrobina käytetään kolibakteeria. Tavoitteena oli myös tutkia tällä hetkellä saatavissa olevien LEDien desinfiointitehokkuutta energiatehokkuuden näkökulmasta. Yksittäisistä aallonpituuksista desinfiointitehokkuudeltaan parhaimmaksi osoittautui 260 nm, aallonpituuksien yhdistelmistä tehokkain oli 265 nm:n ja 260 nm:n yhdistelmä. Muilla aallonpituuksien yhdistelmillä ei saavutettu odotettua parempaa desinfiointitehokkuutta. Optiselta teholtaan parhaimmat LEDit, 265 nm, 270 nm ja 275 nm olivat kokeiden perusteella myös energiatehokkuuden kannalta tarkasteltuina parhaimmat sekä yksittäin että yhdistelminä. UVC-aallonpituuksia emittoivien LEDien optisen tehokkuuden paraneminen on edellytys LEDien hyödyntämiselle desinfioinnissa.

Surface characterization of chemically modified fiber, wood and paper

Inorganic-organic sol-gel hybrid coatings can be used for improving and modifying properties of wood-based materials. By selecting a proper precursor, wood can be made water repellent, decay-, moisture- or UV-resistant. However, to control the barrier properties of sol-gel coatings on wood substrates against moisture uptake and weathering, an understanding of the surface morphology and chemistry of the deposited sol-gel coatings on wood substrates is needed. Mechanical pulp is used in production of wood-containing printing papers. The physical and chemical fiber surface characteristics, as created in the chosen mechanical pulp manufacturing process, play a key role in controlling the properties of the end-use product. A detailed understanding of how process parameters influence fiber surfaces can help improving cost-effectiveness of pulp and paper production. The current work focuses on physico-chemical characterization of modified wood-based materials with surface sensitive analytical tools. The overall objectives were, through advanced microscopy and chemical analysis techniques, (i) to collect versatile information about the surface structures of Norway spruce thermomechanical pulp fiber walls and understand how they are influenced by the selected chemical treatments, and (ii) to clarify the effect of various sol-gel coatings on surface structural and chemical properties of wood-based substrates. A special emphasis was on understanding the effect of sol-gel coatings on the water repellency of modified wood and paper surfaces. In the first part of the work, effects of chemical treatment on micro- and nano-scale surface structure of 1st stage TMP latewood fibers from Norway spruce were investigated. The chemicals applied were buffered sodium oxalate and hydrochloric acid. The outer and the inner fiber wall layers of the untreated and chemically treated fibers were separately analyzed by light microscopy, atomic force microscopy and field-emission scanning electron microscopy. The selected characterization methods enabled the demonstration of the effect of different treatments on the fiber surface structure, both visually and quantitatively. The outer fiber wall areas appeared as intact bands surrounding the fiber and they were clearly rougher than areas of exposed inner fiber wall. The roughness of the outer fiber wall areas increased most in the sodium oxalate treatment. The results indicated formation of more surface pores on the exposed inner fiber wall areas than on the corresponding outer fiber wall areas as a result of the chemical treatments. The hydrochloric acid treatment seemed to increase the surface porosity of the inner wall areas. In the second part of the work, three silane-based sol-gel hybrid coatings were selected in order to improve moisture resistance of wood and paper substrates. The coatings differed from each other in terms of having different alkyl (CH3–, CH3-(CH2)7–) and fluorocarbon (CF3–) chains attached to the trialkoxysilane sol-gel precursor. The sol-gel coatings were deposited by a wet coating method, i.e. spraying or spreading by brush. The effect of solgel coatings on surface structural and chemical properties of wood-based substrates was studied by using advanced surface analyzing tools: atomic force microscopy, X-ray photoelectron spectroscopy and time-of-flight secondary ion spectroscopy. The results show that the applied sol-gel coatings, deposited as thin films or particulate coatings, have different effects on surface characteristics of wood and wood-based materials. The coating which has a long hydrocarbon chain (CH3-(CH2)7–) attached to the silane backbone (octyltriethoxysilane) produced the highest hydrophobicity for wood and wood-based materials.

The Combined treatment of UV Light and Titanium Dioxide (TiO2) in Grease Filtration Technique

The aim of this thesis was to identify the best grease removal technique with the application of low power of UV light to TiO2 coated grease filters. The treatment with various power series of ozone generating and ozone free lamps to normal grease filters and TiO2 coated grease filters were examined and the obtained results are compared to each other in this paper. The effect of ozone reaction was observed and compared with the effect of TiO2. The experiments were solely based on the photo oxidation and photo catalytic oxidation reactions. TiO2 is a green catalyst used in the photocatalytic reaction. Sunflower oil was used for grease production and tetracholoroethylene as a solvent. Grease samples were collected from the ventilation duct connected to the cooking hood system. Sample extraction was done in ultrasonic bath with the principle of sonication. The sample analysis was done by FTIR machine. The result determining the concentration of grease was the quantification of saturated C-H bonds in the chosen peak group of the spectrum. A very low power of UVC light functions perfectly with the Titanium dioxide. The experimental results have shown the combined treatment of titanium dioxide and UV light is an effective method in grease removal process. The photocatalytic reaction with titanium dioxide is better than photo oxidation reaction with ozone treatment. Photocatalytic reaction is environmentally friendly, energy efficient and economical.

Annual changes in serum calcium and inorganic phosphate levels and correlation with gonadal status of a freshwater murrel, Channa punctatus (Bloch)

Adult Channa punctatus murrels of both sexes (60-80 g) were collected locally from Ramgarh Lake during the second week of every month (10 individuals of each sex/month) throughout the year. Blood samples were collected and analyzed for serum calcium and phosphate levels by the methods of Trinder (1960) and Fiske and Subbarow (1925), respectively. Gonads were fixed to judge the state of maturation of the fish. Males exhibited no change in serum calcium levels throughout the year in correlation with testicular maturation. However, serum phosphate levels exhibited a rise in correlation with the increased gonadosomatic index. Females showed marked seasonal changes in serum calcium and phosphate levels which were associated with ovarian maturation (vitellogenesis).

Regulation of the expression of NADP-malic enzyme by UV-B, red and far-red light in maize seedlings

The induction of nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME) in etiolated maize (Zea mays) seedlings by UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400-700 nm) was investigated by measuring changes in activity, protein quantity and RNA levels as a function of intensity and duration of exposure to the different radiations. Under low levels of PAR, exposure to UV-B radiation but not UV-A radiation for 6 to 24 h caused a marked increase in the enzyme levels similar to that observed under high PAR in the absence of UV-B. UV-B treatment of green leaves following a 12-h dark period also caused an increase in NADP-ME expression. Exposure to UV-B radiation for only 5 min resulted in a rapid increase of the enzyme, followed by a more gradual rise with longer exposure up to 6 h. Low levels of red light for 5 min or 6 h were also effective in inducing NADP-ME activity equivalent to that obtained with UV-B radiation. A 5-min exposure to far-red light following UV-B or red light treatment reversed the induction of NADP-ME, and this effect could be eliminated by further treatment with UV-B or red light. These results indicate that physiological levels of UV-B radiation can have a positive effect on the induction of this photosynthetic enzyme. The reducing power and pyruvate generated by the activity of NADP-ME may be used for respiration, in cellular repair processes and as substrates for fatty acid synthesis required for membrane repair.

The use of filter paper plasticized with polyvinyl alcohol-glutaraldehyde in ELISA

F1-antigen purified from Yersinia pestis was covalently linked to 5-mm diameter filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde. These discs were used both for ELISA and dot-ELISA for the detection of anti-F1 IgG in rabbits. The best conditions were achieved using 1.25 µg of F1 antigen/disc, 3% w/v skim milk in PBS as blocking agent, anti-IgG peroxidase conjugate diluted 12,000 times, and serum from rabbits immunized or not against Y. pestis, diluted 6,400 times. The absorbance values obtained from the comparative study between this procedure and conventional ELISA were not significantly different but the low cost of the reagents employed in ELISA using the filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde makes this method economically attractive.

Ultraviolet light protection and weathering properties of wood-polypropylene composites

The main aim of this thesis is to study the effect of pigments on the weathering properties of wood-polypropylene composites (WPC). The studied properties are color change, water absorption, thickness swelling and Charpy impact strength. The impact of weathering and UV exposure on WPCs was studied by using pigments and minerals as protective agents. The study shows that the pigments and/or mineral fillers can be used to improve the weathering properties of WPCs. The effect of pigments was found to vary with the type of pigment and the method of weathering. The black pigment, an inorganic carbon black master-batch, was found to be the most effective one in reduction of the discoloration of WPCs. By preventing discoloration, and further reducing the degradation of the surface of the WPC, the pigments were found to reduce the decrease in the impact strength after weathering. As well as UV protection, the moisture resistance is a significant factor affecting the durability of WPCs. The addition of mineral fillers was found to improve the moisture-related properties, such as water absorption and thickness swelling, of WPC significantly. According to the findings, addition of pigments and mineral fillers to wood-polypropylene composites appears to be beneficial: color stability and moisture resistance can be enhanced especially in outdoor weathering. The combined effect of black pigment (carbon black master-batch) and wollastonite as a mineral filler was found to bring about the most effective properties against weathering.

Polysiloxane/PVA-glutaraldehyde hybrid composite as solid phase for immunodetections by ELISA

We developed an efficient method to prepare a hybrid inorganic-organic composite based on polyvinyl alcohol (PVA) and polysiloxane using the sol-gel disc technique. Antigen obtained from Yersinia pestis was covalently immobilized onto these discs with glutaraldehyde and used as solid phase in ELISA for antibody detection in serum of rabbits experimentally immunized with plague. Using 1.25 µg antigen per disc, a peroxidase conjugate dilution of 1:4,000 and a serum dilution of 1:200 were adequate for the establishment of the procedure. These values are similar to those used for PVA-glutaraldehyde discs, plasticized filter paper discs and the polyaniline-Dacron composite discs. This procedure is comparable to that which utilizes the adsorption of the antigen to conventional PVC plates, with the amount of antigen being one fourth that employed in conventional PVC plates (5 µg/well). In addition to the performance of the polysiloxane/PVA-glutaraldehyde disc as a matrix for immunodetection, its easy synthesis and low cost are additional advantages for commercial application.

Kalman filter for computational market dynamics

Kalman filter is a recursive mathematical power tool that plays an increasingly vital role in innumerable fields of study. The filter has been put to service in a multitude of studies involving both time series modelling and financial time series modelling. Modelling time series data in Computational Market Dynamics (CMD) can be accomplished using the Jablonska-Capasso-Morale (JCM) model. Maximum likelihood approach has always been utilised to estimate the parameters of the JCM model. The purpose of this study is to discover if the Kalman filter can be effectively utilized in CMD. Ensemble Kalman filter (EnKF), with 50 ensemble members, applied to US sugar prices spanning the period of January, 1960 to February, 2012 was employed for this work. The real data and Kalman filter trajectories showed no significant discrepancies, hence indicating satisfactory performance of the technique. Since only US sugar prices were utilized, it would be interesting to discover the nature of results if other data sets are employed.

Initialization of Continuous Nonlinear Models Using Extended Kalman Filter

The two main objectives of Bayesian inference are to estimate parameters and states. In this thesis, we are interested in how this can be done in the framework of state-space models when there is a complete or partial lack of knowledge of the initial state of a continuous nonlinear dynamical system. In literature, similar problems have been referred to as diffuse initialization problems. This is achieved first by extending the previously developed diffuse initialization Kalman filtering techniques for discrete systems to continuous systems. The second objective is to estimate parameters using MCMC methods with a likelihood function obtained from the diffuse filtering. These methods are tried on the data collected from the 1995 Ebola outbreak in Kikwit, DRC in order to estimate the parameters of the system.

Comparative effects of organic and inorganic mercury on in vivo dopamine release in freely moving rats

The present study was carried out in order to compare the effects of administration of organic (methylmercury, MeHg) and inorganic (mercury chloride, HgCl 2 ) forms of mercury on in vivo dopamine (DA) release from rat striatum. Experiments were performed in conscious and freely moving female adult Sprague-Dawley (230-280 g) rats using brain microdialysis coupled to HPLC with electrochemical detection. Perfusion of different concentrations of MeHg or HgCl 2 (2 µL/min for 1 h, N = 5-7/group) into the striatum produced significant increases in the levels of DA. Infusion of 40 µM, 400 µM, or 4 mM MeHg increased DA levels to 907 ± 31, 2324 ± 156, and 9032 ± 70% of basal levels, respectively. The same concentrations of HgCl 2 increased DA levels to 1240 ± 66, 2500 ± 424, and 2658 ± 337% of basal levels, respectively. These increases were associated with significant decreases in levels of dihydroxyphenylacetic acid and homovallinic acid. Intrastriatal administration of MeHg induced a sharp concentration-dependent increase in DA levels with a peak 30 min after injection, whereas HgCl 2 induced a gradual, lower (for 4 mM) and delayed increase in DA levels (75 min after the beginning of perfusion). Comparing the neurochemical profile of the two mercury derivatives to induce increases in DA levels, we observed that the time-course of these increases induced by both mercurials was different and the effect produced by HgCl 2 was not concentration-dependent (the effect was the same for the concentrations of 400 µM and 4 mM HgCl 2 ). These results indicate that HgCl 2 produces increases in extracellular DA levels by a mechanism differing from that of MeHg.

Probing the SERCA1a sarcoplasmic reticulum Ca2+-ATPase phosphorylation-site mutant D351E with inorganic phosphate

The expression of sarcoplasmic reticulum SERCA1a Ca2+-ATPase wild-type and D351E mutants was optimized in yeast under the control of a galactose promoter. Fully active wild-type enzyme was recovered in yeast microsomal membrane fractions in sufficient amounts to permit a rapid and practical assay of ATP hydrolysis and phosphoenzyme formation from ATP or Pi. Mutant and wild-type Ca2+-ATPase were assayed for phosphorylation by Pi under conditions that are known to facilitate this reaction in the wild-type enzyme, including pH 6.0 or 7.0 at 25ºC in the presence of dimethylsulfoxide. Although glutamyl (E) and aspartyl (D) residue side chains differ by only one methylene group, no phosphoenzyme could be detected in the D351E mutant, even upon the addition of 40% dimethylsulfoxide and 1 mM 32Pi in the presence of 10 mM EGTA and 5 mM MgCl2. These results show that in the D351E mutant, increasing hydrophobicity of the site with inorganic solvent was not a sufficient factor for the required abstraction of water in the reaction of E351 with Pi to form a glutamylphosphate (P-E351) phosphoenzyme moiety. Mutation D351E may disrupt the proposed alignment of the reactive water molecule with the aspartylphosphate (P-D351) moiety in the phosphorylation site, which may be an essential alignment both in the forward reaction (hydrolysis of aspartylphosphate) and in the reverse reaction (abstraction of water upon formation of an aspartylphosphate intermediate).