A simulation tool for flight dynamics and control investigations of three different Vertical Take Off and Landing (VTOL) unmanned aircraft configurations has been developed. A control concept has been proposed in order to take advantage of the fast response characteristics of the ordinary small engine/propeller propulsion systems in such aircraft, as well as replacing the complex rotors used previously in VTOL concepts for small unmanned aircraft. The simulation model has been established on the basis of the proposed concept so that it can also be used to study the feasibility of this idea. An Object-based methodology has been introduced so as to reduce the amount of aerodynamic required data for the simulation model. The equations of motion associated with the aircraft multibody system with ten degrees of freedom have been derived using the Newton-Euler method. The modelling of various subsystems including the propeller model, the airframe aerodynamics and the engine model has been carried out. A method for calculating the propellers' slipstream effects on the other components has been presented. Input data for the simulation model have been estimated, using different sources. The Advanced Continuous Simulation Language (ACSL) has been used for the programming of the mathematical model. A series of comprehensive tests have been carried out in order to demonstrate the validity of the simulation model. The ability of the simulation model to explain the aircraft modes of motion as well as to discover unknown nonlinear behaviours and to describe them has been demonstrated.

5 pp. / Urban run-off is created by rain, snowmelt, or irrigation water flowing across sidewalks, drive ways, roadways, and other surfaces into storm drains. All storm drains empty into rivers or river beds, lakes, streams, washes, and other storage areas often without treatment. The Urban Run-off (Non-point Source Pollution) Tip Sheet will educate the reader on urban run-off and associated water pollution. The tip sheet explains the causes, effects, and sources of non-point source pollution. It also provides information on what can be done to prevent urban run-off and water pollution. It includes both general information as well as information specific to Maricopa County.

No description available.

A number of experiments were carried out to study the potential of denitrifying bacteria and reduced nitrogen compounds for control of soil-borne damping-off pathogens. Measurement of the rhizosphere pH of growing soybean roots was carried out in soil adjusted to different pH states and packed into sheet microcosms. The results showed that the rhizosphere pH of soybean was lower than the bulk soil. Nitrate reductase activity and nitrite production was then characterised for the rhizosphere of intact 14 day-old soybean roots that were incubated in nitrate substrates adjusted to different pH values under water-logged conditions. The results showed that the rate and the quantity of nitrite production increased with increasing nitrate concentration and pH in the solution. A growth room experiment was carried out to determine root colonization by denitrifying bacteria in relation to disease caused by soil-borne pathogens, which are favoured by high soil moisture (approximately -5 KPa) and low oxygen levels. Nitrite producing bacteria were isolated from soybean roots grown in Grampian (Insch) soils which had not been cropped with soybean and Thai (Phitsanulok) soils which previously had been cropped with soybean. In the first pot experiment, the nitrite producing bacteria were isolated from different root sections of 12 and 19 day-old soybean plants after 8 weeks of continuous cropping of soils with soybean (a new crop was planted every week), and using different isolation media in order to determine the genus/species composition of the denitrifying bacteria on the rhizoplane. The results showed that continuous cropping of Thai soil and Insch soil with soybean increased pre-emergence damping-off disease and decreased fresh weight yields in seedlings that did emerge. ANOVA showed significant differences between root sections for most bacterial groups monitored {Bacillus spp., Pseudomonas and Enterobacteriaceae), with regression analysis generally showing densities increasing with root age or toward the shoot base. All nitrite producing bacterial isolates were screened for antifungal activity against Macrophomina phaseolina on agar plates and between 10 and 25% of nitrite producing bacteria were found to show in vitro antagonism. In a second pot experiment, the nitrite producing bacteria were isolated from root tissue below the crown (5 cm in length) every 2 weeks of continuous cropping of soils with soybean (a new crop was planted every 2 weeks). Plate-counting was carried out to determine the population of nitrite producing bacteria while a liquid culture MPN method was used for determination of NO, N2O and N2 producing bacteria. Linear regression analysis of the incidence of pre-emergence damping-off and soybean yields in seedling that did emerge showed a highly significant negative correlation between these parameters for both soils. ANOVA showed that there was a significant difference between soil type, with the Thai soil showing higher population densities of antagonistic bacteria on soybean roots. All nitrite producing bacterial isolates were screened for antifungal activity, but the plant pathogenic fungus, Pythium ultimum, was used in this experiment. The results showed that between 10 and 40% of nitrite producing bacteria showed in vitro antagonism. However, regression analysis showed that there was no significant increase or decrease in the nitrite producing antagonistic bacterial population with continuous soybean cropping. All 900 isolates of nitrite producing bacteria isolated from the soybean rhizoplane were screened for antagonistic activity towards Pythium ultimum based on a pot trial assay in the greenhouse. As expected, very low numbers of nitrite producing bacteria showed activity against P. ultimum and only one isolate gave a significant reduction in disease incidence in pot trials. The interactive effects of nitrite producing antagonist and an Arbuscular Mycorrhizal fungus (Glomus mosseae) and Bradryrhizobium japonicum, on control of the fungal pathogens, P. ultimum or M. phaseolina were investigated in the greenhouse. The results showed that improved plant growth was obtained with certain combined inocula involving nitrite producing bacterial antagonists, Glomus mosseae and Bradryrhizobium japonicum.

Mobile devices, such as smartphones and other personal devices, are increasingly used to view maps and other large datasets. Their necessarily small displays can only show a small portion of the data at one time. Researchers have developed various visual techniques that overlay icons or shapes onto the edge of the display to provide the user with hints regarding the existence and location of undisplayed points of interest. However, current techniques fail in practice on mobile devices because they are confusing, do not scale or take up too much valuable screen space. In this thesis, I describe a new technique to visualize the location of off-screen points of interest. This technique, called Wedge, addresses specific shortcomings of existing techniques. This thesis details the design and implementation of Wedge and summarizes the results of a thorough experimental evaluation. Furthermore, I present a preliminary model of user performance that I use to highlight design suggestions for practitioners using Wedge. / February 2009

A hybrid bearing designed for use in a next generation turbo-pump is evaluated for the performance of initial lift-off, referred to as start-transient. The radial test rig features a high-speed spindle motor capable of 20,000 rpm that drives a 718 Inconel rotor attached via a high-speed coupling. The drive end is supported by ceramic ball bearings, while the hybrid bearing supports the opposite end. A magnetic bearing delivers the applied loading along the mid-span of the rotor. Many parameters, including ramp rate [rpm/s] (drive torque), supply pressure at 15,000 rpm, magnitude of the applied load, and load orientation, are varied to simulate different start-transient scenarios. The data are recorded in .dat files for future evaluation of transient predictions. Analysis of the data includes an evaluation of hydrodynamic and hydrostatic liftoff, an assessment of rub from passing through a lightly damped critical speed, and observation of pneumatic hammer instability. Hydrodynamic lift-off occurs when the hydrodynamic pressure, resulting from the relative motion of two surfaces, overcomes the forces acting on the rotor; no indication of hydrodynamic lift-off is provided. Hydrostatic lift-off results from the external supply pressure (which for this test rig is speed dependent) overcoming the forces acting on the rotor as determined from rotor centerline plots. With 0.263 bar applied unit load in the vertical direction, hydrostatic lift-off occurs at 0 rpm and 2.08 bar supply pressure. With a much higher load of 1.53 bar, hydrostatic lift-off is at 12,337 rpm and 10.7 bar supply pressure. The required supply pressure for hydrostatic lift-off is approximately a linear function of the applied unit load. In a turbopump, hydrostatic lift-off depends on the speed because the supply pressure is proportional to the speed squared. With the load in the horizontal direction, hydrostatic lift-off occurs at lower speeds and pressures. The ramp rate did not affect the required supply pressure for hydrostatic lift-off. A lower supply pressure at 15,000 rpm lowered the required supply pressure for hydrostatic liftoff as well as the natural frequencies creating a rub. The hydrostatic lift-off speed should be minimized to avoid damage to the rotor/bearing surfaces due to contact.

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Schlüsselseiten aus dem Exemplar der SLUB Dresden: Diss.jur.civ.447,26.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 253-262). Available also in a digital version from Dissertation Abstracts.

Fertilizer phosphorus (P) application rate and method are anticipated to have important influences on crop utilization and concentration and distribution of residual P in soil. This, in turn, can influence the amount of P removed in run-off water. The objective of this thesis work was to assess the influence of fertilizer P application method and rate on soybean (Glycine max (L.)) emergence, yield, and P uptake. Additionally, the forms and distribution of residual soil P following a season of crop growth, and the off-site export of applied P in simulated snowmelt run-off water was assessed. In a controlled environment study, soybean could tolerate up to 20 kg P2O5 ha-1 placed in the seed-row without significant reduction in emergence. Soybean was grown in a field study in 2014 in south-central Saskatchewan. Two sites were utilized within the same wheat stubble field (Downslope and Upslope) where fertilizer P was soil applied in the spring (seed-placed, deep band, and broadcast and incorporated) at 20 kg P2O5 ha-1 and broadcast at three rates (20, 40, and 80 kg P2O5 ha-1), along with a control treatment receiving no fertilizer P. At the Downslope position, in-soil application of fertilizer P resulted in a greater soybean yield and P uptake than broadcast application. After harvest, higher labile P concentrations were found in the zone of fertilizer P placement in the soil. Elevated concentrations of water soluble P were noted near the soil surface with broadcast P application compared to in-soil placement methods, attributed to immobility of P and lower plant utilization. A simulated snowmelt run-off event was conducted on intact soil slabs removed from the Upslope position treatments. Fertilizer P application method had a significant influence on P export with the greatest export occurring with broadcast application. Phosphorus XANES spectroscopy provided further evidence that, qualitatively, fertilizer P application method influenced speciation of fertilizer P reaction products in calcareous soil common to the Canadian prairies. Overall, it is concluded that in-soil placement of P fertilizer is a beneficial management practice in a prairie soil to maximize agronomic benefit while minimizing potential transport of fertilizer P off the field in snowmelt run-off water.