When a permanent magnet is considered for an application, the quantity that quantifies the usability of that material is the magnetic energy product (BH)max. In today’s world, rare earth transition metal permanent magnets like Nd-Fe-B, Sm-Co possesses the maximum magnetic energy product. But still for the industrial application, the ferrite permanent magnets are the primary choice over these rare transition metal magnets. Thus, in the present context, the magnetic energy product of the low cost ferrite system makes it unsuitable for the high magnetic energy application. In this regard, exchange spring magnets which combine the magnetization of the soft phase and coercivity of the hard magnetic phases become important in enhancing the magnetic energy product of the system. In this thesis, the exchange spring behaviour is reported for the first time in hard/soft oxide nanocomposites by microstructural tailoring of hard Barium Ferrite and soft Nickel Zinc Ferrite particles. We have analyzed the magnetization reversal and its correlation with the coercivity mechanism in the Ni0.8Zn0.2Fe2O4/BaFe12O19 exchange spring systems. Using this exchange spring concept, we could enhance the magnetic energy product in Iron Oxide/ Barium Calcium Ferrite nanocomposites compared to the bare hard ferrite by ~13%. The presence of the exchange interaction in this nanocomposite is confirmed by the Henkel plot. Moreover, a detailed Reitveld study, magnetization loop and corresponding variation of the magnetic energy product, Henkel plot analysis and First Order Reversal Curve analysis are performed on nanocomposites of hard Strontium Ferrite and soft Cobalt Ferrite. We have proved the exchange spring behaviour in this composite. In addition, we could successfully tailor the magnetization behaviour of the soft Cobalt Ferrite- hard Strontium Ferrite nanocomposite from non exchange spring behaviour to exchange spring behaviour, by tuning the size of the soft Cobalt Ferrite in the Cobalt Ferrite/Strontium Ferrite nanocomposite. The relative strength of the interaction governing the magnetization process in the composites has been studied using Henkel plot and First Order Reversal Curve method. The FORC method has been utilized to understand the magnetization reversal behaviour as well as the extent of the irreversible magnetization present in both the nanocomposites, having smaller and larger particle size of the Cobalt Ferrite. It has been found that for the all the studied composites, the pinning is the dominant process for magnetization reversal. The detailed structural analysis using thin film XRD, angle dependent magnetic hysteresis and remanent coercivity measurement, coercivity mechanism by micromagnetic analysis and First Order Reversal Curve analysis are performed for thin films of Strontium Ferrite which are grown on c-plane alumina using Pulsed Laser Deposition (PLD) at two different oxygen partial pressures. The magnetic easy directions of both the films lie in the out of plane direction where as the in plane direction corresponds to the magnetic hard direction. Depending on the oxygen partial pressure during deposition, the magnetization reversal changes from S-W type reversal to Kondorsky kind of reversal. Thus, the growth parameter for the Strontium Ferrite single layer which will be used further as a hard layer for realizing oxide exchange spring in oxide multilayer, is optimized. The details of the magnetic and structural properties are analyzed for Nickel Zinc Ferrite thin film grown on (100) MgAl2O4. We have obtained an epitaxial growth of Nickel Zinc Ferrite by tuning the growth parameters of PLD deposition. The ferromagnetic resonance and the angle dependent hysteresis loop suggest that, the magnetic easy direction for the soft Nickel Zinc Ferrite lie in the film plane whereas the out of plane direction is the magnetic hard direction. Using the growth condition of respective Nickel Zinc Ferrite and Strontium Ferrite, we have realized the exchange spring behaviour for the first time in the trilayer structure of SrFe12O19 (20 nm)/Ni0.8Zn0.2Fe2O4(20 nm)/ SrFe12O19 (20 nm) grown on c-plane alumina (Al2O3) using PLD. The FORC distribution for this trilayer structure shows the single switching behaviour, corresponding to the exchange spring behaviour. The reversible ridge measurement shows that the reversible and the irreversible part of the magnetizations are not coupled with each other.

This project focuses on web security. Some of the most famous vulnerabilities, known troubling web applications. Has been collected and analyzed. Each vulnerability collected in this project, was exploited and secured. Demon- strations from a web application prototype, developed for this project. Brings real examples for each vulnerability, both secured, and insecured. The proto- type ran on a Tomcat web server, and was developed with frameworks such as Web, Spring and Hibernate. Connected to one PostgreSQL data source. All vulnerabilities was successfully implemented in Spring framework, and they were all exploited. Every vulnerability was also secured, with different tools and methods from earlier mentioned frameworks. As a result, real examples from the prototype is used for demonstration in the project, both in a secure and an insecure state. The result views Spring as a framework with good security potential. Most of the Spring specific vulnerabilities, are logical design flaws from developers that can be avoided. Vulnerabilities not related to Spring, such as the one collected for this project. Could be prevented by using methods from the Spring framework or intelligent programming. Which leads to conclusions. Web applications are always exposed to attacks, no matter the framework in use. Creative hackers search to discover new vul- nerabilities, and update old ones all the time. Developers has a responsibility, towards the web applications users. Web applications can not just developed for normal use, but also against possible misuse. Frameworks with good reputation and well processed models, is a good ground for developing a secure application.

The literature suggests that grain number largely determines and as such limits yield in barley. Many of the reported studies were conducted in relatively low yielding environments and it is unclear if grain number is also a limiting factor in high yield potential climates. Nor is it known with certainty what physiological or morphological traits must be targeted in order to increase grain number. There may be a degree of trade-off between yield components whereby grain number is adjusted according to resource availability to the plant, either pre- or post-anthesis, in a way that ensures consistently well-filled grains at harvest. If mechanisms exist for adjusting grain numbers or grain storage capacity after anthesis to match assimilate availability, this may place limits on how far yield can be increased without increasing post-anthesis assimilate production. In order to determine the scope for increasing the yield potential of barley a more thorough understanding of the potential trade-offs between grain number, grain storage capacity and post-anthesis assimilate supply is required. The aim of research reported in this thesis was to establish what determines the yield of spring barley in Ireland and to investigate the timing and possible mechanisms involved in regulating grain number and grain storage capacity in relation to the supply of photoassimilates. Field experiments were carried out on spring barley (Hordeum vulgare L., cv. Quench) at several locations in Ireland from 2011 to 2013. A sub-set of experiments involving destructive sampling and in-field assessments on plots managed as per current best farm practice gathered crop growth, development, and yield component data across sites and seasons in order to establish what determines yield under typical crop production conditions. Separate experiments artificially manipulated the source:sink ratio of plots via shading and seed rate treatments to investigate in more detail the mechanisms determining grain number and grain weight and any potential trade-off between the two components. Grain number accounted for most of the variation in yield across 9 site/seasons of crops managed as per current best practice in Ireland (P < 0.001; R2 = 0.84) while grain weight remained relatively conserved. Ear number accounted for most of the variation in grain number (P = 0.002; R2 = 0.75) and ear number itself was largely determined by shoot survival from an early season peak through to harvest (P <0.001; R = 0.96). Shoot size and weight at the beginning of stem extension had the largest influence on shoot survival. Shading treatments were used to test whether there was a mechanism for adjusting grain numbers after anthesis to match the availability of assimilate for grain filling. Substantial post-anthesis reductions in assimilate supply during grain filling in 2011 and 2012 did not significantly reduce grain number (P > 0.05). A small reduction in grain number (8%) was found in response to shading for a two week period early post-anthesis in 2013, however this was likely a reduction in grain set in shoots or spikelets that reached anthesis after the treatment was imposed rather than a post-anthesis abortion or down-regulation of grain number. Percentage light interception by well managed (unshaded) canopies shortly after anthesis was generally greater than 93% across several sites and seasons, therefore increasing grain numbers to increase sink capacity would likely be associated with an unavoidable decrease in the amount of light intercepted per grain during the early grain development period. However, experiments showed that grain weight at harvest was neither reduced nor increased in response to variations in light interception during this period of endosperm development (P > 0.05), because soluble sugar concentrations in the grain were maintained at the expense of storage reserve deposition in the stems. Results suggest that grain number and grain storage capacity may both be determined pre-anthesis resulting in a trade-off during stem extension whereby grain numbers are adjusted in a way that helps conserve grain weight. A strong negative relationship between ear number and grain number per ear (P < 0.001; R2 = 0.81) across two sites of seed rate experiments in 2013 resulted in a plateau in overall grain number of approximately 18,000 grains m-2 suggesting that there may be a limit to how many grains can be established in a given environment; this was achieved with an ear number of approximately 1000 ears m-2. Yield potential for Irish conditions was estimated at 12.29 t ha-1 at 85% dry matter based on estimates of potential assimilate supply during grain filling; with a grain number of 26,481 m-2 required to utilise this. These estimates are both 44% higher than the mean yield and grain number achieved in crops managed as per current best farm practice. Once high potential ear numbers are secured (> 1000 m-2), breaking the negative relationship between ear number and grain number per ear may hold the key to further increasing grain number and hence yield potential. Increasing assimilate production and partitioning to ears during stem extension, either through increases in the duration of stem extension or solar radiation use efficiency, may enable larger grain numbers to be produced whilst maintaining or increasing individual grain storage capacity and deposition of stem storage reserves. Water and nutrient availability, as well as susceptibility to lodging may present further limitations to yield in the future.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第16400号 / 工博第3481号 / 新制||工||1526(附属図書館) / 29031 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 引原 隆士, 教授 田畑 修, 准教授 山田 啓文 / 学位規則第4条第1項該当

This essay consists of a case study of Tunisian democratization process which came along the events of the Arab spring in 2010-11. The aim of the research is to understand why Tunisia took a distinctive path during the uprisings in the Middle East and North Africa in 2010-11. The case study is within the theoretical framework of traditional democratization literature. These theories are modernization theory, historical sociology and the agency approach. Using the methodological approach of qualitative content analysis, I have analyzed academic articles and come to the conclusion that seven factors played a crucial role for democracy in Tunisia: (1) increased level of education, (2) increased level of information, (3) existing formal and informal organizations in the civil society, (4) transnational power structure, (5) the size of coercive apparatus, (6) compromises among political actors and (7) existing political community. I argue that both the structure of the civil society and the political foundation in Tunisia played a vital role for the distinctive path it took towards democracy.

The purpose of this study is to mitigate the compromise between ride comfort and handling of a small single seat off-road vehicle known as a Baja. This has been achieved by semi-active control of the suspension system containing controllable magnetorheological (MR) dampers and passive hydro-pneumatic spring-damper units. MR fluid is a viscous fluid whose rheological properties depend on the strength of the magnetic field surrounding the fluid, and typically consists of iron particles suspended in silicone oil. When a magnetic field is applied to the fluid, the iron particles become aligned and change the effective viscosity of the fluid. The use of MR fluid in dampers provides variable damping that can be changed quickly by controlling the intensity of the magnetic field around the fluid. Various benefits associated with the use of MR dampers have led to their widespread implementation in automotive engineering. Many studies on conventional vehicles in the existing literature have demonstrated the conflicting suspension requirements for favourable ride comfort and handling. Generally, soft springs with low damping are ideal for improved ride comfort, while stiff springs with high damping are required for enhanced handling. This has resulted in the development of passive suspension systems that provide either an enhanced ride quality or good drivability, often targeting one at the expense of the other. The test vehicle used for this study is distinct in many ways with multiple characteristics that are not commonly observed in the existing literature. For instance, the absence of a differential in the test vehicle driveline causes drivability issues that are aggravated by increased damping. The majority of existing MR damper models in the literature are developed for uniform excitation and re-characterisation of model parameters is required for changes in input conditions. Although recursive models are more accurate and applicable to a wider range of input conditions, these models require measured force feedback which may not always be available due to limitations such as packaging constraints. These constraints required the development of alternative MR damper models that can be used to prescribe the current input to the damper. In this study parametric, nonparametric and recursive MR damper models have been developed and evaluated in terms of accuracy, invertibility and applicability to random excitation. The MR damper is used in parallel with passive damping as a certain amount of passive damping is always present in suspension systems due to friction and elastomeric parts. Most of the existing studies on suspension systems have been performed using linear two degree of freedom vehicle models that are constrained to specific conditions. Usually these models are implemented without an indication of the ability of these models to accurately represent the vehicles that these studies are intended for. For this study, a nonlinear, three-dimensional, 12 degrees of freedom vehicle model has been developed to represent the test vehicle. This model is validated against experimental results for ride comfort and handling. The MR damper models are combined with the model of the test vehicle, and used in ride comfort and handling simulations at various levels of passive damping and control gains in order to assess the potential impact of suspension control on the ride quality and drivability of the test vehicle. Simulation results show that lower passive damping levels can significantly improve the ride comfort as well as the handling characteristics of the test vehicle. Furthermore, it is observed that additional improvements that may be obtained by the implementation of continuous damping control may not be justifiable due to the associated cost and complexity. / Dissertation (MEng)--University of Pretoria, 2013. / Mechanical and Aeronautical Engineering / unrestricted

Master of Arts / Department of Geography / John A. Harrington Jr / In late summer and fall, many migratory birds journey south from the North American Great Plains to spend the winter in locations with greater food availability. As spring returns, a combination of genetics and environmental cues trigger these birds to return north to their breeding grounds. Several bird migration phenology studies from Europe, Australia, and the eastern/northern United States have discovered that some bird species are returning earlier in the spring, a change that has often been correlated with a warming climate. This study aimed to be the first to analyze possible changes in both spring bird migration phenology and regional spring climate change in Kansas. First arrival dates (FADs) were collected for thirty bird species, resulting in a database with over 6,000 FAD entries. For northeast Kansas, 1997-2007 median arrival dates were calculated and compared to dates published by Dr. Richard Johnston in 1965. In southcentral Kansas, 1997-2007 and 1947-1967 median arrival dates were calculated and compared. Temperature data from spring (February through May) were also obtained from the National Climate Data Center's United States Historical Climatology Network for all stations within northeast and south central Kansas and temporal trends were analyzed with linear regression analysis. A comparison between median arrival dates in northeast Kansas found that eleven species had altered their arrival date by a potentially significant number of days. Nine of these had advanced their arrival and two showed a delay. In south central Kansas, nine species were shown to have statistically significant differences in median arrival dates between time periods. Six of these showed an advance and three showed a delay. Five species showed the same trend between both regions, with four arriving earlier by an average 9.4 days and one delaying by an average of 4.5 days. Temperature trends for both subregions in Kansas showed significant warming of 1.8-2.6°F (1.0-1.4°C) over the last century, with the largest warming observed in February and associated strongly with increasing minimum temperatures. The results from this study provide the first evidence that some bird species have recently altered the timing of their arrival in Kansas, with a greater shift toward earlier arrival dates. While the majority of these shifts were correlated with spring warming in Kansas, additional research is necessary to determine the precise cause(s) of these phenological shifts. Still, given existing literature and Intergovernmental Panel on Climate Change predictions for continued warming in the next century, continued alterations to bird migration phenology seem likely.

Magister Philosophiae - MPhil / Groundwater is an important water resource to be used to supplement the water demand for the City of Cape Town for present and future generations. Understanding the groundwater occurrence of the Table Mountain area is very important for future groundwater exploitation and management. Apart from the sea in the west, Table Mountain is mostly surrounded by the unconsolidated sediments including the Kirstenbosch, Newlands, and Oranjezicht areas. These areas are rich in groundwater resources, like springs; some of them were utilized, others not. However, there are few studies that focused on spring resource in this area. No up to date information is available for spring resources research and relative data is lacking from local research institutions. In fact, some of the spring resources in the Table Mountain area had been extracted and been utilized for local community for many years. Data and information newly obtained from this study about such groundwater resources will help future groundwater development and management. There are at least 13 springs in the selected study area. Those springs were investigated for groundwater occurrence, because spring is an important manifestation of the underlying aquifer through which groundwater dynamics can be detected. The main objective of the study was to sketch a clear picture of groundwater occurrence and to obtain an improved understanding of how geomorphology affects groundwater flow, its manifestation and quality. Water resources management is also important because this kind of water resource can be used to help meet the water demand of this local area in the future. There is relationship between the topographical features of the Table Mountain and spring occurrence. The research area delineated is used to interpret the relationship. Hydro-geochemical analysis is carried out to indicate the chemical components of the groundwater and to understand the groundwater type and water quality of this particular area. Based on the completed analysis and interpretation of factors influencing discharge and recharge, some good results were obtained and useful information is made available for first time. / South Africa

Die doel van die navorsing wat in hierdie verslag bespreek word, was om ondersoek in te stel na die omrolgedrag van veldvoertuie. Die studie is gedoen deur gebruik te maak van ʼn Land Rover Defender 110 sport nutsvoertuig as eksperimentele voertuig, en ADAMS View as sagteware pakket Die sogenaamde “vishoektoets” is met die basislynvoertuig uitgevoer. Daar is korrelasie verkry tussen die data wat tydens die toetse opgeneem is, en ʼn volledige drie-dimensionele model van die voertuig in ADAMS View. Die basislynsuspensie op die voertuig is vervolgens vervang met ʼn vier toestand semi-aktiewe hidropneumatiese suspensiestelsel of 4S4. Die toetse is herhaal, en korrelasie verkry tussen die toetsdata en die rekenaarmodel. Die rekenaarmodel, met die basislyn suspensiekarakteristieke vervang met die hidropneumatiese suspensiekarakteristieke, is teen hierdie toetsdata geverifieer. Die rekenaarmodel is na korrelasie gebruik om te bepaal watter veer- en demperstellings die effektiefste sal wees om omrol te voorkom. Verder is die model ook gebruik om die effek van rithoogteverlaging op omrolgeneigdheid te bepaal. Die hoeveelheid wat die wiele oplig, is as norm vir omrolgeneigdheid gebruik. Ander parameters, soos giersnelheid, rolsnelheid en rolhoek is ook ondersoek. Uit die studie is dit duidelik dat die 4S4, met die moontlikheid van verstelling aan rithoogte, sinvol aangewend kan word om omrolgeneigdheid te verminder. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2008. / Mechanical and Aeronautical Engineering / unrestricted

Dampening systems are important in heavy vehicles utilized in rough terrains, with purpose to reduce shocks and vibrations with negative influences on the vehicle and, more importantly, on the operator of the vehicle. During the years the heavy vehicles require sturdier construction parts, due to demands on higher load capacity, where the easy solution to scale up the construction parts is not always applicable for dampening systems with nonlinear behavior. Hence, the sturdiness in the design of these dampening systems requires improvement. In this thesis the design of the rubber spring used as rubber spring in Volvo’s articulated hauler A40G is treated. The aim of this thesis is to find alternative design solutions on the rubber spring, improving its lifetime. The usual failure of these rubber springs is crack propagation in the rubber body. In the method of this thesis, alternative design solution are generated in concepts though brain storming, which are adjusted to achieve the desired behavior of the rubber spring through calculations and tested in performance through simulations in Abaqus. From analyzing the generated data, it is concluded that among the tested design solutions, a combination of fewer plates and shaping the plates as thin bowls, results in highest potential increase in lifetime.