Macrophomina phaseolina: density and longevity of microsclerotia in soybean root tissues and free on the soil, and competitive saprophytic ability

In field experiments, the density of Macrophomina phaseolina microsclerotia in root tissues of naturally colonized soybean cultivars was quantified. The density of free sclerotia on the soil was determined for plots of crop rotation (soybean-corn) and soybean monoculture soon after soybean harvest. M. phaseolina natural infection was also determined for the roots of weeds grown in the experimental area. To verify the ability of M. phaseolina to colonize dead substrates, senesced stem segments from the main plant species representing the agricultural system of southern Brazil were exposed on naturally infested soil for 30 and 60 days. To quantify the sclerotia, the methodology of Cloud and Rupe (1991) and Mengistu et al. (2007) was employed. Sclerotium density, assessed based on colony forming units (CFU), ranged from 156 to 1,108/g root tissue. Sclerotium longevity, also assessed according to CFU, was 157 days for the rotation and 163 days for the monoculture system. M. phaseolina did not colonize saprophytically any dead stem segment of Avena strigosa,Avena sativa,Hordeum vulgare,Brassica napus,Gossypium hirsutum,Secale cereale,Helianthus annus,Triticosecalerimpaui, and Triticum aestivum. Mp was isolated from infected root tissues of Amaranthus viridis,Bidens pilosa,Cardiospermum halicacabum,Euphorbia heterophylla,Ipomoea sp., and Richardia brasiliensis. The survival mechanisms of M. phaseolina studied in this paper met the microsclerotium longevity in soybean root tissues, free on the soil, as well as asymptomatic colonization of weeds.

Wear of rotary plows operating in a tropical clay loam soil

The wear resistance of rotary plows operating in a clay loam soil was studied. The degree of damage caused to the soil and the amount of mass lost by the tools were determined in order to establish correlations between the physical properties of the soil and the wear mechanisms acting on the tribosystem. Field tests were carried out in 12 plots and a randomized experimental design with 4 levels, 3 replicas per level and 2 passes per plot was applied. The levels relate to the tillage implements employed: rotary tiller, rotary power harrow, small motorized rotary tiller and control (unaltered soil). The highest mass losses were measured in rotary tiller and rotary power harrow's tools, while the small motorized rotary tiller's tools showed generally lower levels of damage. It was determined that the effective contact time between tool and soil, the rotating speed and the sudden impact forces are the most significant factors affecting the wear resistance in field operations. Thirty days after tillage operation the soil samples were taken from each plot at a mean depth of 100 mm in order to determine bulk density, gravimetric moisture content and percentage of aggregates smaller than 5 mm. No significant differences among the values of these properties were found in the experiments. The wear mechanisms acting on the tools' surface are complex and include 2-body and 3-body abrasion as well as the presence of sudden impact forces.

Modelling of calciner in post-combustion carbon capture process

Climate change has given an impetus to research and developed new technologies to reduce significantly carbon dioxide emissions in energy production in the developed countries. The major pollution source, fossil fuels, will be used as an energy source for many decades, which provides the demand for carbon capture and storage technologies. Over recent years many new technologies has been developed and one of the most promising is calcium-looping in post-combustion carbon capture process, which use carbonation-calcination cycle to capture carbon dioxide from the flue gas of a combustion process. First pilot plant for calcium-looping process has been built in Oviedo, Spain. In this study, a three-dimensional model has been created for the calciner, which is one of the two fluidized bed reactors needed for the process. The calciner is a regenerator where the captured carbon dioxide is removed from the calcium material and then collected after the reactor. Thesis concentrates in creating the calciner 3D-model frame with CFB3D-program and testing the model with two different example cases. Used input parameters and calciner geometry are Oviedo pilot plant design parameters. The calculation results give information about the process and show that pilot plant calciner should perform as planned. This Master’s Thesis is done in participation to EU FP7 project CaOling.

Servo drive in hoist application

The objective of this master thesis is to test according to hoisting requirements, a servo drive system and compare its performance with the performance of a drive equipped with a vector controlled frequency converter. Both systems utilize closed-loop vector control based on PCL program control. In order to compare the results of tests both systems were connected to the same motor driving a variable speed electrical chain hoist. Tests were based on requirements to both systems. As requirements of tests zero speed operation, operation in field weakening, positioning accuracy and smoothness of motion are taken into consideration. Both systems demonstrate quite similar performance and meet the requirements. Servo drive system demonstrates a high positioning accuracy and dynamic performance. Frequency converter is not able to provide the same positioning accuracy and dynamic performance as servo drive.

Covalidation of Integral Transforms and Method of Lines in Nonlinear Convection-Diffusion with Mathematica

The Mathematica system (version 4.0) is employed in the solution of nonlinear difusion and convection-difusion problems, formulated as transient one-dimensional partial diferential equations with potential dependent equation coefficients. The Generalized Integral Transform Technique (GITT) is first implemented for the hybrid numerical-analytical solution of such classes of problems, through the symbolic integral transformation and elimination of the space variable, followed by the utilization of the built-in Mathematica function NDSolve for handling the resulting transformed ODE system. This approach ofers an error-controlled final numerical solution, through the simultaneous control of local errors in this reliable ODE's solver and of the proposed eigenfunction expansion truncation order. For covalidation purposes, the same built-in function NDSolve is employed in the direct solution of these partial diferential equations, as made possible by the algorithms implemented in Mathematica (versions 3.0 and up), based on application of the method of lines. Various numerical experiments are performed and relative merits of each approach are critically pointed out.

Atrazine and picloram adsorption in organic horizon forest samples under laboratory conditions

Adsorption of two herbicides, atrazine and picloram, displaying different sorption characteristics, were evaluated for O (organic) horizon samples collected from SMZs (streamside management zones) in Piedmont (Ultisol) of Georgia, USA. Samples were randomly collected from within 5 SMZs selected for a study of surface flow in field trials. The five SMZs represented five different slope classes, 2, 5, 10, 15 and 20%. Results indicate that 0 horizons have the potential for sorbing atrazine from surface water moving through forested SMZs. Atrazine adsorption was nearly linear over a 24-hour period. Equilibrium adsorption, determined through 24-hour laboratory tests, resulted in a Freundlich coefficient of 67.5 for atrazine. For picloram, negative adsorption was observed in laboratory experiments. This seemed to be due to interference with ELISA analyses; however, this was not confirmed. The adsorption coefficient (Kd) obtained for atrazine in 0 horizons was greater than it would have been expected for mineral soil (from 1 to 4). Picloram was not sorbed in 0 horizons at any significant degree. Although there is a significant potential for the direct adsorption of soluble forms of herbicides in SMZs, the actual value of this adsorption for protecting water is likely to be limited even for relatively strongly sorbed chemicals, such as atrazine, due to relatively slow uptake kinetics.

Influence of seed size and ecological factors on the germination and emergence of field bindweed (Convolvulus arvensis)

An understanding of seed germination ecology of weeds can assist in predicting their potential distribution and developing effective management strategies. Influence of environmental factors and seed size on germination and seedling emergence of Convolvulus arvensis (field bindweed) was studied in laboratory and greenhouse conditions. Germination occurred over a wide range of constant temperatures, between 15 and 40 ºC, with optimum germination between 20 and 25 ºC. Time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased with an increase in temperature from 20 ºC, salinity and osmotic stress. However, germination was tolerant to low salt (25 mM) or osmotic stress (0.2 MPa), but as salinity and osmotic stress increased, germination percentage and germination index decreased. Seeds of C. arvensis placed at soil surface showed maximum emergence and decreased as seeding depth increased. Seeds of C. arvensis germinated over a wide range of pH (4 to 9) but optimum germination occurred at pH 6 to 8. Under highly alkaline and acidic pH, time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased. Increase in field capacity caused decreased time to start germination, time to 50% germination and mean germination time but increased germination percentage and germination index. Bigger seeds had low time to start germination, time to 50% germination and mean germination time but high germination percentage and germination index. Smaller seeds were more sensitive to environmental factors as compared to larger or medium seeds. It can be concluded that except for pH, all environmental factors and seed sizes adversely affect C. arvensis as regards seed germination or emergence and germination or emergence traits, and larger seeds result in improved stand establishment and faster germination than small seeds, regardless of moisture stress or deeper seeding depth.

Nectar and pollen production in pumpkin (Cucurbita pepo L.)

Cucurbitaceae species depend on pollination by honey bees for fruit production. The overall objective of this work was to evaluate the potential of C. pepo for pollen and nectar production, that could help maintain colonies placed in the field. Plants of pumpkin were cultivated in field, in 1996 and 1997. Before anthesis, male flowers were covered to prevent visits by bees and other insects. After anthesis the flowers were uncovered and the following parameters were evaluated: 1) nectar production; 2) total sugar concentration in the nectar; 3) nectar replacement; and 4) production of pollen and flowers during the crop cycle. Nectar production varied from 18 to 79 µL flower-1 and increased progressively from 7h to 13h. The sugar concentration, measured at 7h, 9h and 11h, did not vary, averaging 50.5% ± 0.5% in 1996 and 40.5% ± 0.6% in 1997. At 13h the concentration decreased to 42% in 1996 and to 35% in 1997. Total daily nectar production was not influenced by removing nectar several times per day, indicating that nectar secretion is not stimulated or inhibited by frequent removal. The number of pollen grains did not differ in the two years, with an average of 43,669 ± 1,382 grains per flower. The peak rate of male and female flowers occurred from 60 to 66 days after planting (DAP) with 34.6 male flowers and 2.2 female flowers per plant, respectively. Cucurbita pepo has a potential for honey and pollen production of about 105 and 160 kg per hectare per season, respectively, which is enough to sustain, at least, five honeybee colonies.

From genes to communities : stress tolerance in eelgrass (Zostera marina)

Shallow coastal areas are dynamic habitats that are affected by a variety of abiotic and biotic factors. In addition to the natural environmental stress, estuarine and coastal seagrass ecosystems are exposed to effects of climate change and other anthropogenic impacts. In this thesis the effect of different abiotic (shading stress, salinity and temperature) and biotic stressors (presence of co-occurring species) and different levels and combinations of stressors on the performance and survival of eelgrass (Zostera marina) was assessed. To investigate the importance of scale for stress responses, varying levels of biological organization (genotype, life stage, population and plant community) were studied in field and aquarium experiments. Light limitation, decreased salinity and increased temperature affected eelgrass performance negatively in papers I, II and III, respectively. While co-occurring plant species had no notable effect on eelgrass in paper IV, the presence of eelgrass increased the biomass of Potamogeton perfoliatus. The findings in papers II and III confirmed that more extreme levels of salinity and temperature had stronger impacts on plant performance compared to intermediate levels, but intermediate levels also had more severe effects on plants when they were exposed to several stressors, as illustrated in paper II. Thus, multiple stressors had negative synergetic effects. The results in papers I, II and III indicate that future changes in light climate, salinity and temperature can have serious impacts on eelgrass performance and survival. Stress responses were found to vary among genotypes, life stages and populations in papers I, II and III, respectively, emphasizing the importance of study scale. The results demonstrate that while stress in general affects seagrass productivity negatively, the severity of effects can vary substantially depending on the studied scale or level of biological organization. Eelgrass genotypes can differ in their stress and recovery processes, as observed in paper I. In paper II, eelgrass seedlings were less prone to abiotic stress compared to adult plants, but stress also decreased their survival considerably. This indicates that recruitment and re-colonization through seeds might be threatened in the future. Variation among population responses observed in paper III indicates that long-term local adaptation under differing selection pressures has caused divergence in salinity tolerance between Baltic eelgrass populations. This variability in stress tolerance observed in papers I and III suggests that some eelgrass genotypes and populations have a better capacity to adapt to changes and survive in a changing environment. Multiple stressors and biological level-specific responses demonstrate the uncertainty in predicting eelgrass responses in a changing environment. As eelgrass populations may differ in their stress tolerance both within and across regions, conservation strategies at both local and regional scales are urgently needed in order to ensure the survival of these important ecosystems.

Potential and Challenges of Analog Reconfigurable Computation in Modern and Future CMOS

In this work, the feasibility of the floating-gate technology in analog computing platforms in a scaled down general-purpose CMOS technology is considered. When the technology is scaled down the performance of analog circuits tends to get worse because the process parameters are optimized for digital transistors and the scaling involves the reduction of supply voltages. Generally, the challenge in analog circuit design is that all salient design metrics such as power, area, bandwidth and accuracy are interrelated. Furthermore, poor flexibility, i.e. lack of reconfigurability, the reuse of IP etc., can be considered the most severe weakness of analog hardware. On this account, digital calibration schemes are often required for improved performance or yield enhancement, whereas high flexibility/reconfigurability can not be easily achieved. Here, it is discussed whether it is possible to work around these obstacles by using floating-gate transistors (FGTs), and analyze problems associated with the practical implementation. FGT technology is attractive because it is electrically programmable and also features a charge-based built-in non-volatile memory. Apart from being ideal for canceling the circuit non-idealities due to process variations, the FGTs can also be used as computational or adaptive elements in analog circuits. The nominal gate oxide thickness in the deep sub-micron (DSM) processes is too thin to support robust charge retention and consequently the FGT becomes leaky. In principle, non-leaky FGTs can be implemented in a scaled down process without any special masks by using “double”-oxide transistors intended for providing devices that operate with higher supply voltages than general purpose devices. However, in practice the technology scaling poses several challenges which are addressed in this thesis. To provide a sufficiently wide-ranging survey, six prototype chips with varying complexity were implemented in four different DSM process nodes and investigated from this perspective. The focus is on non-leaky FGTs, but the presented autozeroing floating-gate amplifier (AFGA) demonstrates that leaky FGTs may also find a use. The simplest test structures contain only a few transistors, whereas the most complex experimental chip is an implementation of a spiking neural network (SNN) which comprises thousands of active and passive devices. More precisely, it is a fully connected (256 FGT synapses) two-layer spiking neural network (SNN), where the adaptive properties of FGT are taken advantage of. A compact realization of Spike Timing Dependent Plasticity (STDP) within the SNN is one of the key contributions of this thesis. Finally, the considerations in this thesis extend beyond CMOS to emerging nanodevices. To this end, one promising emerging nanoscale circuit element - memristor - is reviewed and its applicability for analog processing is considered. Furthermore, it is discussed how the FGT technology can be used to prototype computation paradigms compatible with these emerging two-terminal nanoscale devices in a mature and widely available CMOS technology.

Flow in porous media of oil-water systems

Fluid flow behaviour in porous media is a conundrum. Therefore, this research is focused on filtration-volumetric characterisation of fractured-carbonate sediments, coupled with their proper simulation. For this reason, at laboratory rock properties such as pore volume, permeability and porosity are measured, later phase permeabilities and oil recovery in function of flow rate are assessed. Furthermore, the rheological properties of three oils are measured and analysed. Finally based on rock and fluid properties, a model using COMSOL Multiphysics is built in order to compare the experimental and simulated results. The rock analyses show linear relation between flow rate and differential pressure, from which phase permeabilities and pressure gradient are determined, eventually the oil recovery under low and high flow rate is established. In addition, the oils reveal thixotropic properties as well as non-Newtonian behaviour described by Bingham model, consequently Carreau viscosity model for the used oil is given. Given these points, the model for oil and water is built in COMSOL Multiphysics, whereupon successfully the reciprocity between experimental and simulated results is analysed and compared. Finally, a two-phase displacement model is elaborated.

Aktiivisten magneettilaakereiden ohjauslaitteiston vaatimusmäärittely ja toteutus

Aktiivinen magneettilaakeri on järjestelmä joka mahdollistaa pyörivän kappaleen, esimerkiksi sähkökoneen roottorin, leijuttamisen magneettikentässä ilman fyysistä kontaktia vastakappaleiden välillä. Tekniikalla on joitain merkittäviä etuja muihin laakerointijärjestelmiin verrattuna erityisesti suurnopeuksisissa tai puhdastiloissa käytettävissä sähkökäytöissä. Magneettilaakereiden yleistymistä nopeuttaisi ja niiden hintaa laskisi mikäli laakereiden säätöön ja tehonsyöttöön voitaisiin käyttää standardeja teollisuusautomaatiolaitteita erityisesti tätä käyttötarkoitusta varten kehitettyjen laitteiden sijaan. Tässä työssä luodaan menetelmä määrittää vähimmäisvaatimukset aktiivisen magneettilaakerin säätöalgoritmien suorittamiseen käytetylle säätöjärjestelmälle ja anturoinnille sekä laakerin toimintaan tarvittavalle tehoelektroniikalle. Näiden vaatimusten perusteella luodaan katsaus soveltuviin laitteisiin ja kootaan esimerkkikokoonpanot kahdelle erilaiselle magneettilaakeroitavalle kohteelle. Lisäksi työssä esitellään LUT:ssa vuosina 2014-2015 kehitetty magneettilaakerin teholähdeprototyyppi ja selvitetään edellytykset käyttää laitetta laakerijärjestelmän osana.

Mindfulness: An Ancient Wisdom for the Reconceptualisation of Modern Education in the Complex World

Exploring the new science of emergence allows us to create a very different classroom than how the modern classroom has been conceptualised under the mentality of efficiency and output. Working on the whole person, and not just the mind, we see a shift from the epistemic pillars of truth to more ontological concerns as regards student achievement in our post-Modern and critical discourses. It is important to understand these shifts and how we are to transition our own perception and mentality not only in our research methodologies but also our approach to conceptualisations of issues in education and sustainability. We can no longer think linearly to approach complex problems or advocate for education and disregard our interconnectedness insofar as it enhances our children’s education. We must, therefore, contemplate and transition to a world that is ecological and not mechanical, complex and not complicated—in essence, we must work to link mind-body with self-environment and transcend these in order to bring about an integration toward a sustainable future. A fundamental shift in consciousness and perception may implicate our nature of creating dichotomous entities in our own microcosms, yet postmodern theorists assume, a priori, that these dualities can be bridged in naturalism alone. I, on the other hand, embrace metaphysics to understand the implicated modern classroom in a hierarchical context and ask: is not the very omission of metaphysics in postmodern discourse a symptom from an education whose foundation was built in its absence? The very dereliction of ancient wisdom in education is very peculiar indeed. Western mindfulness may play a vital component in consummating pragmatic idealism, but only under circumstances admitting metaphysics can we truly transcend our limitations, thereby placing Eastern Mindfulness not as an ecological component, but as an ecological and metaphysical foundation.

Letter to S.D. Woodruff regarding a resolution passed that the engineer be requested to examine the fence built by the contractors alongside of the Henry Vandenburgh Farm

Letter to S.D. Woodruff regarding a resolution passed that the engineer be requested to examine the fence built by the contractors alongside of the Henry Vandenburgh Farm and report to the secretary as to whether this is a lawful fence, completed according to Williams’ contract. This is signed by Duncan McFarland, president. There is a reply written by S.D. Woodruff at the bottom of the letter stating that the fence is not built in accordance with the contract, Dec. 18, 1856.

Infrared thermography: A non-invasive window into thermal physiology

Infrared thermography is a non-invasive technique that measures mid to long-wave infrared radiation emanating from all objects and converts this to temperature. As an imaging technique, the value of modern infrared thermography is its ability to produce a digitized image or high speed video rendering a thermal map of the scene in false colour. Since temperature is an important environmental parameter influencing animal physiology and metabolic heat production an energetically expensive process, measuring temperature and energy exchange in animals is critical to understanding physiology, especially under field conditions. As a non-contact approach, infrared thermography provides a non-invasive complement to physiological data gathering. One caveat, however, is that only surface temperatures are measured, which guides much research to those thermal events occurring at the skin and insulating regions of the body. As an imaging technique, infrared thermal imaging is also subject to certain uncertainties that require physical modeling, which is typically done via built-in software approaches. Infrared thermal imaging has enabled different insights into the comparative physiology of phenomena ranging from thermogenesis, peripheral blood flow adjustments, evaporative cooling, and to respiratory physiology. In this review, I provide background and guidelines for the use of thermal imaging, primarily aimed at field physiologists and biologists interested in thermal biology. I also discuss some of the better known approaches and discoveries revealed from using thermal imaging with the objective of encouraging more quantitative assessment.