An evaluation of host-plant resistance to the wireworm-Diabrotica-Systena (WDS) complex of root-feeding insects in sweetpotatoes was performed on a total of 15 cultivars and advanced lines over the course of 4 years (2017-2020). It was found that sweetpotatoes varieties can differ significantly in amount of damage incurred. Several mechanisms of resistance were proposed and tested: periderm toughness, dry weight percentage, and volatile organic chemical defenses. No significant difference was found amongst the varieties tested concerning the physical properties. Chemical analysis was limited in scope but did show some differences between a susceptible variety when compared to a resistant variety in the volatile chemical composition of the foliage. Finally, a commercial kairomone lure with sticky card for Diabroticites was tested for efficacy when compared to sweep net sampling throughout the season. No correlation could be found amongst the methods in terms of number and species of insects caught by each.

The aim of this master thesis was to compare EELS in TEM with TEM-EDS and WDS-EPMA for quantitative analysis of γ-phase in cemented carbide. Especially, the quantification of the light elements nitrogen and carbon in compounds like TiCxN1-x is interesting, since this is problematic. The techniques were compared by acquiring spectra for quantification of two samples of cemented carbide containing γ-phase (Tix,W1-x)(CyN1-y) with different nitrogen and tungsten content. Also, a rigorous evaluation about how EELS spectra best is acquired and processed was performed in order to enable the comparison. Experimental results show that EELS gives satisfying results for TiC0.7N0.3 and that EELS is comparable with WDS-EPMA for quantification of nitrogen, carbon and titanium in (Tix,W1-x)(CyN1-y) when the atomic concentration of nitrogen is around 20%. However, EELS was not used for quantification of tungsten. Concluded is also that EELS and WDS should be considered as complementary rather than competing techniques.

Hazardous winds, such as tornadoes and hurricanes, have a great impact on civil engineering structures and cause significant social and economic disturbances. The wind speed and pressure tested in the conventional wind tunnel experiments are much smaller than the actual wind speed and pressure measured in the field. Therefore, the Wind-induced Damage Simulator (WDS) was constructed at the University of Ottawa to overcome the wind speed limitations of wind tunnels and to simulate different types of wind speed profiles. WDS is an isolated cubic box with dimensions 3.65m x3.65 m and 3.0 m height, with multiple inlets on the side faces of the testing chamber and an outlet on the top side. This unique equipment creates a controlled environment for studying wind speed profiles in a confined space, by regulating the air flow with the aid of an attached industrial blower. To measure the simulated wind velocities inside the WDS and to obtain the wind speed profile in the testing chamber, Aeroprobe (12- Hole Probe) sensor was used for different combinations of opened inlets and at four different locations. The data collected from the Aeroprobe was processed by the use of the Aeroflow 2.7.5.7346 software, to get the velocity of wind in three different directions (u, v and w) and the mean velocity at a single point. After determining the mean velocity at different heights and RPM values at all four positions, Matlab software was used to determine the wind profile and the spectra of the turbulence intensities and these were compared for different heights at the four investigated locations and for various rotations per minute (RPM) values (400 to 800 RPM) for controlling the blower. Once the flow characterization was completed, the wind-induced pressure for three models of the Silsoe Cube were measured as a part of the second phase of the test. The current experiment employed 3 different scales of Silsoe cube: 1:40, 1:30 and 1:20, while the pressure coefficients were determined at 16 different points along a vertical line crossing the faces of the cube. A pressure taps system with 16 channels and a Scanivale pressure scanner were used to measure the pressure at 16 different positions on the cube. Matlab software was used to determine the pressure coefficients from the data measured by pressure taps. The pressure coefficienst for the Silsoe Cube were plotted and compared for the three different scales. Also, for determining the best scale to be used in future experiments. The pressure coefficients of the 3 different scaled model of Silsoe Cubes was compared with full-scale data reported in the literature for the same structure. Based on the results obtained from the experiments, recommendations for the best location in the testing chamber for the future experiments employing the WDS were formulated.

This work deals with the corrosion protection of magnesium alloy AZ31, AZ61, AZ91 using fluoride conversion coating prepared from Na[BF4] melt. The theoretical part describes the properties of magnesium alloys, the recent results of fluoride conversion coatings preparation and analysis of the available literature about the properties of salt Na[BF4] and its decomposition products. The experimental part was devided into two main sections. The first deals with the corrosion resistance of the treated magnesium alloys (AZ31, AZ61, AZ91 and AZ91 annealed) in the Na[BF4] melt. Corrosion resistance was tested using potentiodynamic tests and tests in the corrosion chamber. In the second part, the mechanism has been studied for preparing fluoride conversion coating, where it was shown that in air-free atmosphere the oxidizing agent in the process is boron, which is reduced from BIII to B0, and thereby enables the fluoride conversion coating.

The work deals with design and implementation of multi-point wireless network connecting selected end devices (IP cameras). The Access Points (AP) using frequency band 2.4 GHz establish the connection. They are connected using wireless distribution system (WDS). The work briefly describes standard IEEE 802.11g which is base of the design. Practical part is composed of network throughput measuring, signal strength measuring of access points with description and description of all other used devices.

When designing urban water systems (i.e. water distribution and sewer systems) it is imperative that uncertainty is taken into consideration. However, this is a challenging problem due to the inherent uncertainty associated with both system loading requirements and the potential for physical components failure. It is therefore desirable to improve the reliability of each system in order to account for these uncertainties. Although it is possible to directly evaluate the reliability of a water distribution systems (WDS) (using reliability measures), the calculation processes involved are computationally intensive and therefore unsuitable for some state-of-the-art, iterative design approaches (such as optimisation). Consequently, interest has recently grown in the use of reliability indicators, which are simpler and faster to evaluate than conventional direct reliability methods. In this thesis, a novel measure (the RUF) is developed to quantify reliability in urban water systems with a view to enhance their robustness under a range of future scenarios (Policy Reform, Market Forces, Fortress World and New-Sustainability Paradigm). The considered four future scenarios were synthesized in the EPSRC supported multidisciplinary 4 year project: Urban Futures. Each investigated urban future scenario is characterised by a distinct household water demand and local demand distribution (emerging due to different urban forms evolving in future scenarios). In order to assess the impact of urban futures, RUF has been incorporated into Urban Water System (UWS) dynamic simulations for both WDSs and Foul Sewer Systems (FSSs) using open source codes of EPANET and SWMM. Additionally, in order to overcome extensive computational effort, resulting from the use of traditional reliability measures, a new holistic reliability indicator, the hydraulic power entropy (IHPE) has been developed and compared to existing reliability indicators. Additionally, the relationship between the new reliability indicator and the above mentioned RUF reliability measure is investigated. Results suggest that the magnitude of the IHPE in network solutions provides a holistic indication of the hydraulic performance and reliability for a WDS. However, the performance of optimal solutions under some Urban Futures indicates that additional design interventions are required in order to achieve desired future operation. This thesis also proposes a new holistic foul sewer system (FSS) reliability indicator (the IFSR). The IFSR represents sewer performance as a function of excess pipe capacity (in terms of available increase and also decrease in inflow). The indicator has been tested for two case studies (i.e. different sewer network layouts). Results suggest that the magnitude of IFSR has positive correlations with a number of identified key performance indicators (i.e. relating to capacity, velocity, blockages). Finally, an Integrated Design Approach (IDA) has been developed in order to assess the implications of applying design interventions on both a WDS and downstream FSS. The approach holistically considers present and future operation of each interconnected system. The approach was subsequently demonstrated using two proposed design interventions. Results suggest that, for the considered design interventions, there is trade-off between the simultaneous improvement of both WDS and FSS operation and reliability.

The usage of ground-mounted photovoltaic solar panels is increasing, and it is essential to fully understand the wind behavior and loading on the panels, since there is no specific code or guideline for their design in the present. In addition, the University of Ottawa and Carleton University recently developed a new facility, called the Wind Damage Simulator (WDS). This study will allow to understand the flow behavior in the facility, along with the effects of different blower rpm settings on the flow. A CFD study was also conducted, in order to examine the methodology and turbulence models suitable for the flow replicated in this facility, for future research. The newly developed Wind Damage Simulator (WDS) facility was used to examine wind-induced effects on two solar panels attached to a frame. The mean pressure coefficient distribution on the photovoltaic panels was examined for several wind angles of incidence (AOI) and wind speeds. The wind AOI considered were the 0°, 30°, 45°, 180°, 210° and 225°, along with wind speeds ranging from 14 m/s to 42 m/s, with increments of around 2 m/s. The experimental results showed fluctuations in the Cp distribution on the panels, due to the WDS wind flow being highly unstable. The 180° wind AOI led to the highest uplift mean Cp equivalent (Cpeq) value on the panels. The 45° and 180° wind AOI were found to induce a Cpeq of significantly higher magnitude on the first panel compared to the second panel, whereas the 0° and 210° wind AOI induced a significantly higher Cpeq magnitude on the second panel compared to the first panel Cpeq. Moreover, the CFD study provided pressure coefficient distribution on the panels and flow visualization when interacting with the panels surfaces. The LES Dynamic Smagorinsky subgrid scale model was found to be more suitable for the WDS numerical replication than the RANS shear stress transport k-ω turbulence model. The LES model showed the fluctuating pressure coefficients on the panels’ surfaces, induced by the swirls that were formed post interaction of the wind with the panels.

Abstract Methods for tephrochronology are evaluated, in the following way: Lake sediments <500 years old from three small Antarctic lakes were analysed for identification of tephras. Subsamples were analysed for a) grain size, and identification and concentration of volcanogenic grains, b) identification of tephra horizons, c) element abundance by EPMA WDS/EDS and LA-ICP-MS, and d) possible correlations between lakes and volcanoes. Volcanogenic minerals and shards were found all through the sediment cores in all three lakes, in different abundances. A high background population of volcanogenic mineral grains, in all samples, made the identification of tephra horizons difficult, and shards could only be distinguished by certainty after chemical analysis of elements. The tephra layers commonly could not be seen by the naked eye, and, hence they are regarded as cryptotephras. Because of the small size of recent eruptions in the research area, and the travel distance of ash, most shards are small and difficult to analyse. Nine possible tephra horizons have been recorded in the three lakes, and preliminary correlations have been made. But because of analytical problems, the proposed correlations between the lakes and possible volcanic sources are preliminary.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The expected peak water demand in a water distribution system (WDS) is an important consideration for WDS design purposes. In South Africa the most common method of estimating peak demand is by multiplying the average demand by a dimensionless peak factor. A peak factor is the ratio between the maximum flow rate (which refers to the largest volume of flow to be received during a relatively short time period, say , expressed as the average volume per unit time), and the average flow rate over an extended time period. The magnitude of the peak factor will vary, for a given daily water demand pattern, depending on the chosen value of . The design guidelines available give no clear indication of the time intervals most appropriate for different peak factor applications. It is therefore important to gain a better understanding regarding the effect of on the derived peak factor. A probability based end-use model was constructed as part of this study to derive diurnal residential indoor water demand patterns on a temporal scale of one second. These stochastically derived water demand patterns were subsequently used to calculate peak factors for different values of , varying from one second to one hour. The end-use model derived the water demand patterns by aggregating the synthesised end-use events of six residential indoor end-uses of water in terms of the water volume required, duration and the time of occurrence of each event. The probability distributions describing the end-use model parameters were derived from actual end-use measurements that had previously been collected in a noteworthy North-American end-use project (Mayer et al., 1999). The original comprehensive database, which included water measurements from both indoor and outdoor end-uses, was purchased for use in this project. A single execution of the end-use model resulted in the synthesised diurnal water demand pattern for a single household. The estimated water demand pattern for simultaneous water demand by groups of households was obtained by adding individual iterations of the end-use model, considering group sizes of between one and 2 000 households in the process. A total of 99 500 model executions were performed, which were statistically aggregated by applying the Monte Carlo method and forming 4 950 unique water demand scenarios representing 29 different household group sizes. For each of the 4 950 water demand scenarios, a set of peak factors was derived for eight selected values. The end-use model presented in this study yielded realistic indoor water demand estimations when compared to publications from literature. In agreement with existing knowledge, as expected, an inverse relationship was evident between the magnitude of the peak factors and . The peak factors across all time intervals were also found to be inversely related to the number of households, which agreed with other publications from literature. As the number of households increased, the degree to which the peak factor was affected by the time intervals decreased. This study explicitly demonstrated the effect of time intervals on peak factors. The results of this study could act as the basis for the derivation of a practical design guideline for estimating peak indoor flows in a WDS, and the work could be extended in future to include outdoor water demand and sensitivity to WDS pressure. / AFRIKAANSE OPSOMMING: Die verwagte water spitsaanvraag is ‘n belangrike oorweging in die ontwerp van ‘n waterverspreidingsnetwerk. Die mees algemene metode in Suid Afrika om spitsaanvraag te bereken is deur die gemiddelde wateraanvraag te vermeningvuldig met ‘n dimensielose spitsfaktor. ‘n Spitsfaktor is die verhouding tussen die maksimum watervloei tempo (wat verwys na die grootste volume water wat ontvang sal word tydens ‘n relatiewe kort tydsinterval, , uitgedruk as die gemiddelde volume per tyd eenheid), en die gemiddelde watervloei tempo gedurende ‘n verlengde tydsinterval. Die grootte van die spitsfaktor sal varieer vir ‘n gegewe daaglikse vloeipatroon, afhangende van die verkose waarde. Die beskikbare ontwerpsriglyne is onduidelik oor watter tydsintervalle meer geskik is vir die verskillende spitsfaktor toepassings. Daarom is dit belangrik om ‘n beter begrip te verkry ten opsigte van die effek van op die verkrygde spitsfaktor. ‘n Waarskynliksheidsgebaseerde eindverbruik model is opgestel om deel te vorm van hierdie studie, om daaglikse residensiële binnenshuise wateraanvraag patrone af te lei op ‘n temporale skaal van een sekonde. Die stogasties afgeleide wateraanvraag patrone is daarna gebruik om die verskeie spitsfaktore te bereken vir verskillende waardes van , wat varieer vanaf een sekonde tot een uur. Die eindverbruik model stel die daaglikse vloeipatroon van een huis saam deur die eindeverbruik gebeure van ses residensiële binnenshuise eindverbruike saam te voeg in terme van the vereiste water volume en die tyd van voorkoms van elke gebeurtenis. Die waarskynliksheids distribusie wat die eindverbruik model parameters omskryf is verkry van werklike gemete eindverbruik waardes, wat voorheen in ‘n beduidende Noord-Amerikaanse eindverbruik projek (Mayer et al. 1999) versamel is. Die oorspronklike en omvattende databasis, wat gemete waardes van binnenshuis en buite water verbruik ingesluit het, is aangekoop vir gebruik gedurende hierdie projek. ‘n Enkele uitvoering van die eindverbruik model stel gevolglik ‘n daaglikse wateraanvraag patroon saam vir ‘n elkele huishouding. Die wateraanvraag patroon vir gelyktydige water verbruik deur groepe huishoudings is verkry deur individuele iterasies van die eindverbruik model statisties bymekaar te tel met die Monte Carlo metode, terwyl groep groottes van tussen een en 2 000 huishoudings in die proses oorweeg is. ‘n Totaal van 99 500 model uitvoerings is gedoen, wat saamgevoeg is om 4 950 unieke watervraag scenarios voor te stel, wat verteenwoordigend is van 29 verskillende huishouding groep groottes. Vir elkeen van die 4 950 watervraag senarios, is ‘n stel spitsfaktore afgelei vir agt verkose waardes. Die eindverbruik model aangebied in hierdie studie lewer ‘n realistiese binnenshuise wateraanvraag skatting, wanneer dit vergelyk word met verslae in die literatuur. Ooreenkomstig met bestaande kennis is ‘n sterk inverse verhouding sigbaar tussen die grootte van die spitsfaktore en . Dit is ook gevind dat die spitsfaktore oor al die tydsintervalle ‘n inverse verband toon tot die aantal huishoudings, wat ooreenstemmend is met ander publikasies in die literatuur. Soos die aantal huishoudings toeneem, het die mate waartoe die spitsfaktor geaffekteer is deur die tydsintervalle afgeneem. Hierdie studie toon duidelik die effek van tydsintervalle op spitsfaktore. Die resultaat van hierdie studie kan dien as basis om praktiese ontwerpsriglyne te verkry in die skatting van binnenshuise spitsvloei in ‘n waterverspreidingsnetwerk, gegewe dat die werk in die toekoms uitgebrei kan word om ook buitenshuise waterverbruik in te sluit, asook sensitiwiteit tot druk in die waterverspreidingsnetwerk.

This thesis describes theoretic proposal and two practical realization of multi - point wireless network, first for communications between two endpoints and second for wireless signal coverage of a structured space. The wireless network is realized by the equipment working in unlicenced 2,4GHz and 5GHz ISM band. The wireless device are configured in three different wireless mods: WDS, WDS bridge and AP. This paper contains short information about IEEE 802.11a/b/g/n standard and associated proprietary wireless specifications. Practical workshop describes several variants connections and present the result of throughtput measurements, depending on wireless network topology.