Streamside management zone (SMZ) efficiency in herbicide retention from simulated surface flow

Plot-scale overland flow experiments were conducted to evaluate the efficiency of streamside management zones (SMZs) in retaining herbicides in runoff generated from silvicultural activities. Herbicide retention was evaluated for five different slopes (2, 5, 10, 15, and 20%), two cover conditions (undisturbed O horizon and raked surface), and two periods under contrasting soil moisture conditions (summer dry and winter wet season) and correlated to O horizon and site conditions. Picloram (highly soluble in water) and atrazine (moderately sorbed into soil particles) at concentrations in the range of 55 and 35 µg L-1 and kaolin clay (approximately 5 g L-1) were mixed with 13.000 liters of water and dispersed over the top of 5 x 10 m forested plots. Surface flow was collected 2, 4, 6, and 10 m below the disperser to evaluate the changes in concentration as it moved through the O horizon and surface soil horizon-mixing zone. Results showed that, on average, a 10 m long forested SMZ removed around 25% of the initial concentration of atrazine and was generally ineffective in reducing the more soluble picloram. Retention of picloram was only 6% of the applied quantity. Percentages of mass reduction by infiltration were 36% for atrazine and 20% for picloram. Stronger relationships existed between O horizon depth and atrazine retention than in any other measured variable, suggesting that better solid-solution contact associated with flow through deeper O horizons is more important than either velocity or soil moisture as a determinant of sorption.

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.

Kestomagneettitahtikonekäyttöjen erot

Permanent magnet drives with nominal power over 10 kW were not a cost-sufficient system 25 years ago due to high material expenses. The improvements in motor drives, the rise in competition and the tightening of standards and regulations have caused that the PM-drives are more and more common in the over 10 kW nominal power range. The goal of this thesis is to research the performance in relation to nominal power of a PM-drive technique that is vastly increasing its popularity in fan related devices. The studied motor technique brushless direct current drive (BLDC) consists of a voltage source inverter, permanent motor and six-step-control. The reference drive is a brushless alternating current drive (BLAC) which consists of a VSI, PM and a hysteresis control. As a conclusion there are no major obstacles that would impede the BLDC-drive technique from expanding to larger power stages. The following factors must be taken into consideration when designing a BLDC-drive: motor’s current change rate, inverter switching frequency, motor’s nominal electric frequency, phase inductance and the current handling capability of the inverter. The fluctuating material costs create instability to the end prices of PM-motors that can in the worst case lead to diminished interest towards BLDC- and PM-drives in general.

Design of a 1 kW 150 rpm permanent-magnet synchronous generator for stand-alone wind-power applications

A program for calculating low-speed low-power synchronous machine is presented. A permanent-magnet synchronous generator for 1 kW 150 rpm is designed. Optimization of magnet’s and coil’s dimensions was made.

Reverse osmosis membrane surface modification: effects on membrane performance

The aim of this thesis was to study the surface modification of reverse osmosis membranes by surfactants and the effect of modification on rejection and flux. The surfactants included anionic and nonionic surfactants. The purpose of membrane modification was to improve pure water permeability with increasing salt rejection. The literature part of the study deals with the basic principles of reverse osmosis technology and factors affecting the membrane performance. Also the membrane surface modification by surfactants and their influence on membrane’s surface properties and efficiency (permeability and salt rejection) were discussed. In the experimental part of the thesis two thin-film composite membranes, Desal AG and LE-4040, were modified on-line with three different surfactants. The effects of process parameters (pressure, pH, and surfactant concentration) on surface modification were also examined. The characteristics of the modified membranes were determined by measuring the membranes’ contact angle and zeta potentials. The zeta potential and contact angle measurements indicate that the surfactants were adsorbed onto the both membranes. However, the adsorption did not effect on membrane’s pure water permeability and salt rejection. Thereby, the surface modification of the Desal AG and LE-4040 membranes by surfactants was not able to improve the membrane’s performance.

Modal testing and numerical modeling of the dynamic properties of layered sheet-steel structure

Recently, due to the increasing total construction and transportation cost and difficulties associated with handling massive structural components or assemblies, there has been increasing financial pressure to reduce structural weight. Furthermore, advances in material technology coupled with continuing advances in design tools and techniques have encouraged engineers to vary and combine materials, offering new opportunities to reduce the weight of mechanical structures. These new lower mass systems, however, are more susceptible to inherent imbalances, a weakness that can result in higher shock and harmonic resonances which leads to poor structural dynamic performances. The objective of this thesis is the modeling of layered sheet steel elements, to accurately predict dynamic performance. During the development of the layered sheet steel model, the numerical modeling approach, the Finite Element Analysis and the Experimental Modal Analysis are applied in building a modal model of the layered sheet steel elements. Furthermore, in view of getting a better understanding of the dynamic behavior of layered sheet steel, several binding methods have been studied to understand and demonstrate how a binding method affects the dynamic behavior of layered sheet steel elements when compared to single homogeneous steel plate. Based on the developed layered sheet steel model, the dynamic behavior of a lightweight wheel structure to be used as the structure for the stator of an outer rotor Direct-Drive Permanent Magnet Synchronous Generator designed for high-power wind turbines is studied.

Cyanobacterial occurrence and detection of microcystin by planar chromatography in surface water of Billings and Guarapiranga Reservoirs, SP, Brazil

Billings and Guarapiranga Reservoirs were deeply affected by environmental disturbances, which more evident consequence are the cyanobacterial blooms. Microcystins are the most common cyanotoxin in freshwaters and more than 70 types are known. Different methods for microcystins analysis in water can be used, among which ELISA and HPLC are the most frequently employed. However, less sophisticated and more economic methods can also be used. This is the case of planar chromatography (thin-layer chromatography) method previously used in cyanotoxins purification but gradually replaced by others. Posterior optimization of the microcystin chromatography conditions and because of its simplicity, rapidity, efficiency and low cost, this method is again considered an option for the analysis of microcystins and nodularins. Considering the importance of Billings and Guarapiranga Reservoirs for drinking water supplies and the few scientific data about cyanobacteria and cyanotoxins in these water bodies, the aims of this work are to analyze the biodiversity of cyanobacteria in the Billings and Guarapiranga Reservoirs and the detection of dissolved microcystins in the water. It was possible to identify 17 species of cyanobacteria, 9 of them being potentially toxic. In Billings Reservoir Microcystis aeruginosa (Kützing) Kützing and Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju are the most common species, while in Guarapiranga Reservoir only M. aeruginosa was considered as a common species. Microcystins were detected in all Billings Reservoir samples and in only one sample from Guarapiranga Reservoir.

Influence of surface functionalization on the behavior of silica nanoparticles in biological systems

Personalized nanomedicine has been shown to provide advantages over traditional clinical imaging, diagnosis, and conventional medical treatment. Using nanoparticles can enhance and clarify the clinical targeting and imaging, and lead them exactly to the place in the body that is the goal of treatment. At the same time, one can reduce the side effects that usually occur in the parts of the body that are not targets for treatment. Nanoparticles are of a size that can penetrate into cells. Their surface functionalization offers a way to increase their sensitivity when detecting target molecules. In addition, it increases the potential for flexibility in particle design, their therapeutic function, and variation possibilities in diagnostics. Mesoporous nanoparticles of amorphous silica have attractive physical and chemical characteristics such as particle morphology, controllable pore size, and high surface area and pore volume. Additionally, the surface functionalization of silica nanoparticles is relatively straightforward, which enables optimization of the interaction between the particles and the biological system. The main goal of this study was to prepare traceable and targetable silica nanoparticles for medical applications with a special focus on particle dispersion stability, biocompatibility, and targeting capabilities. Nanoparticle properties are highly particle-size dependent and a good dispersion stability is a prerequisite for active therapeutic and diagnostic agents. In the study it was shown that traceable streptavidin-conjugated silica nanoparticles which exhibit a good dispersibility could be obtained by the suitable choice of a proper surface functionalization route. Theranostic nanoparticles should exhibit sufficient hydrolytic stability to effectively carry the medicine to the target cells after which they should disintegrate and dissolve. Furthermore, the surface groups should stay at the particle surface until the particle has been internalized by the cell in order to optimize cell specificity. Model particles with fluorescently-labeled regions were tested in vitro using light microscopy and image processing technology, which allowed a detailed study of the disintegration and dissolution process. The study showed that nanoparticles degrade more slowly outside, as compared to inside the cell. The main advantage of theranostic agents is their successful targeting in vitro and in vivo. Non-porous nanoparticles using monoclonal antibodies as guiding ligands were tested in vitro in order to follow their targeting ability and internalization. In addition to the targeting that was found successful, a specific internalization route for the particles could be detected. In the last part of the study, the objective was to clarify the feasibility of traceable mesoporous silica nanoparticles, loaded with a hydrophobic cancer drug, being applied for targeted drug delivery in vitro and in vivo. Particles were provided with a small molecular targeting ligand. In the study a significantly higher therapeutic effect could be achieved with nanoparticles compared to free drug. The nanoparticles were biocompatible and stayed in the tumor for a longer time than a free medicine did, before being eliminated by renal excretion. Overall, the results showed that mesoporous silica nanoparticles are biocompatible, biodegradable drug carriers and that cell specificity can be achieved both in vitro and in vivo.

Kestomagnetoidun roottorin mekaniikkasuunnittelu ja -analysointi

Työssä kehitettiin suurnopeuskäyttöön soveltuva kestomagnetoitu roottori olemassa olevan induktiokoneen staattorirunkoon. Kehitystyön tarkoituksena oli selvittää roottorin mekaaniset raja-arvot, kuten maksimi kehänopeus. Samalla otettiin kantaa myös tarvittaviin analysointi- ja mitoitusmenetelmiin. Maksimi kehänopeuden, laakeroinnin ja roottorin skaalattavuuden selvittäminen edellytti myös tarkkaa materiaaliselvitystä ja optimointia. Tästä syystä työn aikana tehtiin tiivistä yhteistyötä materiaalitoimittajien kanssa. Työn tuloksena syntyi uusi menetelmä toteuttaa radiaalisen magneettivuon luova kestomagneettiroottori 200 m/s kehänopeudelle. Suunniteltua roottoriratkaisua käytetään testausroottorina, jolla selvitetään valmistuksen, kokoonpanon ja sähkötehon rajoitteet käytännössä. Suunnittelutyö edellyttikin jatkuvaa iterointia sähkösuunnittelun ja roottorin osien valmistajien kanssa, jotta löydettiin paras kompromissiratkaisu roottorin prototyyppiin. Tämän seurauksena saatiin luotua varsin tarkat suunnittelu- ja analysointiraja-arvot kestomagneettiroottorin tuotteistettavia versioita varten.

Proteolytic release and partial characterization of human sperm-surface glycopeptides

Sperm-surface glycopeptides were obtained from intact sperm membranes after proteolytic release by different enzymatic treatments such as autoproteolysis, trypsin, papain and pronase. Glycopeptides were isolated, their properties and composition were examined, and their monosaccharide and amino acid constituents were characterized. The monosaccharides identified were fucose, mannose, galactose, N-acetylglucosamine, and N-acetylgalactosamine, which form part of more than one type of oligosaccharide units. Autoproteolytic treatment mainly provided O-glycosidic type oligosaccharides, while a mixture of O- and N-glycosidic oligosaccharides was obtained in variable proportions when treated with trypsin, papain or pronase. The highest degree of peptide cleavage was obtained with pronase. Despite the higher yields reached with trypsin, these glycopeptides contain the lowest percentage of oligosaccharide chains. Proteolytic treatment provides a simple, rapid procedure for the isolation of glycopeptides from the sperm surface

Respiratory effects of kynurenic acid microinjected into the ventromedullary surface of the rat

Several studies demonstrate that, within the ventral medullary surface (VMS), excitatory amino acids are necessary components of the neural circuits involved in the tonic and reflex control of respiration and circulation. In the present study we investigated the cardiorespiratory effects of unilateral microinjections of the broad spectrum glutamate antagonist kynurenic acid (2 nmol/200 nl) along the VMS of urethane-anesthetized rats. Within the VMS only one region was responsive to this drug. This area includes most of the intermediate respiratory area, partially overlapping the rostral ventrolateral medulla (IA/RVL). When microinjected into the IA/RVL, kynurenic acid produced a respiratory depression, without changes in mean arterial pressure or heart rate. The respiratory depression observed was characterized by a decrease in ventilation, tidal volume and mean inspiratory flow and an increase in respiratory frequency. Therefore, the observed respiratory depression was entirely due to a reduction in the inspiratory drive. Microinjections of vehicle (200 nl of saline) into this area produced no significant changes in breathing pattern, blood pressure or heart rate. Respiratory depression in response to the blockade of glutamatergic receptors inside the rostral VMS suggests that neurons at this site have an endogenous glutamatergic input controlling the respiratory cycle duration and the inspiratory drive transmission.

Expression of anti-Z-DNA single chain antibody variable fragment on the filamentous phage surface

We describe the expression of an anti-Z-DNA single chain variable region antibody fragment (scFv) on a filamentous phage surface. Four vectors for phage display were constructed. Two of them are able to display multiple copies of the antibody fragment, and the others can be used to make monovalent libraries. The vectors use different promoter/leader sequences to direct the expression of the fused proteins. All were able to promote the assembly of fusion virion particles. In this paper we also show the affinity selection (biopanning) of those phage-antibodies based on the capacity of their products to recognize the antigen. We used biotinylated Z-DNA and the selection was performed in a solution phase fashion. The data presented here indicate that these vectors can be further used to construct anti-nucleic acid antibody fragment libraries that can be used to study the basis of nucleic acid-protein interaction and its role in autoimmunity mechanisms.

Studies of the small bowel surface by scanning electron microscopy in infants with persistent diarrhea

We describe the ultrastructural abnormalities of the small bowel surface in 16 infants with persistent diarrhea. The age range of the patients was 2 to 10 months, mean 4.8 months. All patients had diarrhea lasting 14 or more days. Bacterial overgrowth of the colonic microflora in the jejunal secretion, at concentrations above 10(4) colonies/ml, was present in 11 (68.7%) patients. The stool culture was positive for an enteropathogenic agent in 8 (50.0%) patients: for EPEC O111 in 2, EPEC O119 in 1, EAEC in 1, and Shigella flexneri in 1; mixed infections due to EPEC O111 and EAEC in 1 patient, EPEC O119 and EAEC in 1 and EPEC O55, EPEC O111, EAEC and Shigella sonnei in 1. Morphological abnormalities in the small bowel mucosa were observed in all 16 patients, varying in intensity from moderate 9 (56.3%) to severe 7 (43.7%). The scanning electron microscopic study of small bowel biopsies from these subjects showed several surface abnormalities. At low magnification (100X) most of the villi showed mild to moderate stunting, but on several occasions there was subtotal villus atrophy. At higher magnification (7,500X) photomicrographs showed derangement of the enterocytes; on several occasions the cell borders were not clearly defined and very often microvilli were decreased in number and height; in some areas there was a total disappearance of the microvilli. In half of the patients a mucus-fibrinoid pseudomembrane was seen partially coating the enterocytes, a finding that provides additional information on the pathophysiology of persistent diarrhea.

Surface studies of limestones and dolostones : characterisation using various techniques and batch dissolution experiments with hydrochloric acid solutions

In this thesis, stepwise titration with hydrochloric acid was used to obtain chemical reactivities and dissolution rates of ground limestones and dolostones of varying geological backgrounds (sedimentary, metamorphic or magmatic). Two different ways of conducting the calculations were used: 1) a first order mathematical model was used to calculate extrapolated initial reactivities (and dissolution rates) at pH 4, and 2) a second order mathematical model was used to acquire integrated mean specific chemical reaction constants (and dissolution rates) at pH 5. The calculations of the reactivities and dissolution rates were based on rate of change of pH and particle size distributions of the sample powders obtained by laser diffraction. The initial dissolution rates at pH 4 were repeatedly higher than previously reported literature values, whereas the dissolution rates at pH 5 were consistent with former observations. Reactivities and dissolution rates varied substantially for dolostones, whereas for limestones and calcareous rocks, the variation can be primarily explained by relatively large sample standard deviations. A list of the dolostone samples in a decreasing order of initial reactivity at pH 4 is: 1) metamorphic dolostones with calcite/dolomite ratio higher than about 6% 2) sedimentary dolostones without calcite 3) metamorphic dolostones with calcite/dolomite ratio lower than about 6% The reactivities and dissolution rates were accompanied by a wide range of experimental techniques to characterise the samples, to reveal how different rocks changed during the dissolution process, and to find out which factors had an influence on their chemical reactivities. An emphasis was put on chemical and morphological changes taking place at the surfaces of the particles via X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). Supporting chemical information was obtained with X-Ray Fluorescence (XRF) measurements of the samples, and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) measurements of the solutions used in the reactivity experiments. Information on mineral (modal) compositions and their occurrence was provided by X-Ray Diffraction (XRD), Energy Dispersive X-ray analysis (EDX) and studying thin sections with a petrographic microscope. BET (Brunauer, Emmet, Teller) surface areas were determined from nitrogen physisorption data. Factors increasing chemical reactivity of dolostones and calcareous rocks were found to be sedimentary origin, higher calcite concentration and smaller quartz concentration. Also, it is assumed that finer grain size and larger BET surface areas increase the reactivity although no certain correlation was found in this thesis. Atomic concentrations did not correlate with the reactivities. Sedimentary dolostones, unlike metamorphic ones, were found to have porous surface structures after dissolution. In addition, conventional (XPS) and synchrotron based (HRXPS) X-ray Photoelectron Spectroscopy were used to study bonding environments on calcite and dolomite surfaces. Both samples are insulators, which is why neutralisation measures such as electron flood gun and a conductive mask were used. Surface core level shifts of 0.7 ± 0.1 eV for Ca 2p spectrum of calcite and 0.75 ± 0.05 eV for Mg 2p and Ca 3s spectra of dolomite were obtained. Some satellite features of Ca 2p, C 1s and O 1s spectra have been suggested to be bulk plasmons. The origin of carbide bonds was suggested to be beam assisted interaction with hydrocarbons found on the surface. The results presented in this thesis are of particular importance for choosing raw materials for wet Flue Gas Desulphurisation (FGD) and construction industry. Wet FGD benefits from high reactivity, whereas construction industry can take advantage of slow reactivity of carbonate rocks often used in the facades of fine buildings. Information on chemical bonding environments may help to create more accurate models for water-rock interactions of carbonates.

Numerical simulation of rotor-stator interaction and tip clearance flow in centrifugal compressors

The effect of the tip clearance and vaneless diffuser width on the stage performance and flow fields of a centrifugal compressor were studied numerically and results were compared to the experimental measurements. The diffuser width was changed by moving the shroud side of the diffuser axially and six tip clearances size from 0.5 to 3 mm were studied. Moreover, the effects of rotor-stator interaction on the diffuser and impeller flow fields and performance were studied. Also transient simulations were carried out in order to investigate the influence of the interaction on the impeller and diffuser performance parameters. It was seen that pinch could improve the performance and it help to get more uniform flow at exit and less back flow from diffuser to the impeller.