The problem of how the Sun's corona is heated is of central importance to solar physics research. In this thesis we model three main areas. The first, annihilation, is a feature of non-ideal MHD and focusses on how magnetic field of opposite polarity meets at a null point and annihilates, after having been advected with plasma toward a stagnation point in the plasma flow. Generally, the null point of the field and the stagnation point of the flow are coincident at the origin, but in chapter 2 a simple extension is considered where an asymmetry in the boundary conditions of the field moves the null point away from the origin. Chapter 3 presents a model of reconnective annihilation in three dimensions. It represents flux being advected through the fan plane of a 3D null, and diffusing through a thin diffusion region before being annihilated at the spine line, and uses the method of matched asymptotic expansions to find the solution for small values of the resistivity. The second area of the thesis covers null collapse. This is when the magnetic field in close proximity to a null point is disturbed, causing the field to fold up on itself and collapse. This is a feature of ideal MHD, and causes a strong current to build up, allowing non-ideal effects to become important. When using linearised equations for the collapse problem, we are in fact looking at a linear instability. If this instability initiates a collapse, this is only a valid model until non-linear effects become important. By talking about collapse in chapters 4 and 5 (as it is talked about in the literature), we mean that the linear instability initiates collapse, which in principle, non-linear effects could later stop. Chapter 4 introduces a two-dimensional model for collapse, using the ideal, compressible, linearised MHD equations. It is a general solution in which all spatially linear nulls and their supporting plasma flows and pressure gradients can be checked for susceptibility to collapse under open boundary conditions. Chapter 5 uses the model introduced in chapter 4 to investigate the collapse of three-dimensional, potential nulls (again, spatially linear) for all possible supporting plasma flows and pressure gradients. Using this model, all nulls under consideration are found to collapse and produce large currents, except for a group of 2D O-type nulls supported by highly super-Alfvenic plasma flows. The third area of this thesis involves numerically simulating a model of heating by coronal tectonics (Priest et al, 2002). A simple magnetic field is created and the boundary is driven, also in a simple manner. Current sheets which scale with grid resolution are seen to build up on the quasi-separatrix layers, and there is some evidence of magnetic reconnection.

This study analyzes the relation between accounting conservatism, future tax rate cuts and countries' level of book-tax conformity. Firms have an incentive to increase conservatism in financial reporting when a tax rate cut is imminent to shift taxable income into the lower taxed future. Using a panel of firms across 18 countries from 1995 to 2010 I find that conditional conservatism is positively and significantly associated with future tax rate cuts when book-tax conformity is high. This effect is particularly pronounced for firms that concentrate the majority of their operations in the country in which the tax rate is cut. In contrast, there is no significant relation between future tax rate cuts and unconditional conservatism. / Series: WU International Taxation Research Paper Series

A significant growth was witnessed in the field of Wireless Sensor Networks (WSNs), in the previous decade. The objective of this study has been Survey of micro controllers and short-range radio transceivers for wireless sensors and provide an extensive overview of micro controllers and RF-transceivers in the Market and compare the relevant properties for designing wireless sensor nodes. In the survey, RF-transvers from Nordic semiconductors is extensively presented for short-rang wireless protocols some of the protocols are RF-Communication Module, Bluetooth Low Energy Module, ZigBee module and Wi-Fi module.          In WSNs node design Power consumption is one the most important design issue, this thesis work present the different type of WSN protocols energy consumption efficiency and power consumption, compared and conclude graphically.        Microcontrollers are the main part of WSNs node for processing and gathering sensor data. There is different microcontroller’s products in the market however the WSN protocols presented in this thesis uses Cortex-M4 processor which is one of ARM product, the specification and comparison of this product with other products is presented.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1966. / Includes bibliographical references (leaves 49-53). / Surface ozone concentrations were measured in the Greater Boston area from November, 1964 to December, 1965. Ozone was monitored continuosly using a Mast microcoulombmetric sensor. A chromium trioxide filter was fitted to the air inlet of the sensor in order to remove negatively interfering sulphur dioxide. Daily ozone concentrations near the surface varied from somewhat greater than 10 to less than 1 pphm by volume. The highest concentrations occurred in late spring while the lowest concentrations occurred in the winter. Such a seasonal variation would be expected if the ozone had arrived in the troposphere from the lower stratosphere. The concentration of ozone during the spring and early summer showed a much greater variability from day to day than was exhibited during the fall and winter months. / by Donald Allen Widen. / M.S.

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The technology in cellular phones, portable computing systems, intelligent- andconnected- devices are evolving in a high pace and in many cases these devices arerequired to operate in a low-power environment. The problem that continues toemerge, is the power consumption in microcontrollers and DSP devices. This issue hasover time become important to solve in order to maximize battery life. To ease thechoice of power efficient microcontrollers, controlled experiments were thereforeperformed with the Cortex-M4, this microcontroller was chosen because of theupgraded hardware, which has led to an appreciable change in both power- and speedefficiency compared to its predecessors.The conclusion presents important points, along with advantages and difficulties toconsider when implementing a DSP application. By comparing different optimizationswith the Floating Point Unit(FPU), Fixed-point and software Floating-point, the resultsshow that there are major differences in power consumption between these threeoptions. Depending on which option and optimization used then the powerconsumption can exceed over 70% more compared to the other options available.

The study reported here originated in my therapeutic work with children at risk and my search for a therapeutic approach which would help them develop the inner strength to cope with their difficulties. The concept of ‘meaning in life' as a source of strength has been extensively and richly studied among older age groups, both with respect to the different personal meanings which everyone finds in their life and with respect to the effect on one's life of possessing a sense of 'meaning in life', but it has been neglected almost entirely among children. As a result, the aim of this research was to further knowledge about the concept of 'meaning in life' for children. Due to the paucity of research with children regarding this issue, it was needed to first establish that meaning in life was at all a relevant and researchable concept for children. Consequently, the primary research questions were as follows: Does the concept of ‘meaning in life' have relevance for children? Relatedly, what are the (dis)connections between children's understandings of their own lives, and what matters to them, and, the adult concept of ‘meaning in life? To examine these over-arching questions, the following four sub-questions were devised: - What do children think are the most important and meaningful things in their lives? - What do children think is the best way to live life? - What nature of goals and purpose do children have for their lives and do they believe that they have character traits and strengths which would help them to fulfil their goals/purpose? - How do children's individuality and the differences between them show themselves in their perspectives on meaning in life? To what extent is gender associated with variations in response? The research adopted a Constructivist-Phenomenological approach, with the aim of getting as close as possible to the children's own perceptions and experience of their world. Thirty eight-year-old children in their third year at two primary schools in different neighbourhoods of the same central Israeli city were interviewed using semi-structured interviews. This data collection approach was complemented by two creative elements: a short semi-humorous story told at the start to set the tone of the interview, and a picture drawn at the end of the interview by the children to illustrate what was important in their life. Some interviews were carried out individually and some as a group. The data analysis method chosen was Smith's (1996) and Smith and Osborn's (2008) Interpretative Phenomenological Analysis (IPA). This thesis makes two original contributions to knowledge. The first is the discovery that meaning in life is as pertinent a concept among children as it is among adults. Children may not understand the concept of 'meaning in life' in as full a way as an adult might, but they do have clear and well-shaped opinions about the most important things in their lives (e.g. family and friends) and how they should best live (e.g. by helping others and living in peace). They have goals and plans for the future (e.g. Ambitions to become a pilot or teacher) and they believe that they have traits and strengths that will help them in reaching their goals (e.g. that being wise, kind or curious will help them in life). The second important contribution is methodological: the research technics developed in this study (the semi-structured interview enriched by story-telling and picture-drawing) has provided what appears to be a reliable way of generating valid responses from the participants. It could be used by researchers in the future to further understanding about how children perceive the notion of meaning in life.

This thesis focuses on the design and implementation of the wireless localization module, using UWB technology with emphases on low-power firmwre based on RTOS. Wireless localization is based on TDoA algorithm.  The resulting HW module is designed as a four layer PCB, based on MCU crf52832 (ARM Cortex M4) and UWB module DevaWave DW1000. Firmware is implemented using FreeRTOS with emphasis on low power consumption. For hardware implementation, Eagle CAD was used. Firmware is implemented in C and Assembly programming languages.

Main accomplishment of this master’s thesis is to make a module for verification of the function binary and analog inputs (analog inputs only for current loop between 0-20mA) on data logger MODAS DataPoint. Hardware testing device will be made on development kit STM32F3-Discovery from STMicroelecronics Company. Device generates testing signals for confirmation of the function MODAS DataPoint device. Testing device communicates with MODAS DataPoint device via Ethernet, communication between PC application and hardware of the testing device is realized by USB interface in DFU mode. Solution included PC application, where you can connect to the tester device and tested Modas DP device. Furtheremore, the test starts here and application inform user about during a test, processed measured data and generate output protocols.

As part of a large investigation with Hubble Space Telescope to study the faintest stars within the globular cluster omega Centauri, in this work we present early results on the multiplicity of its main sequence (MS) stars, based on deep optical and near-infrared observations. By using appropriate colour-magnitude diagrams, we have identified, for the first time, the two main stellar Populations I and II along the entire MS, from the turn-off towards the hydrogen-burning limit. We have compared the observations with suitable synthetic spectra of MS stars and conclude that the two main sequences (MSs) are consistent with stellar populations with different metallicity, helium and light-element abundance. Specifically, MS-I corresponds to a metal-poor stellar population ([Fe/H] similar to -1.7) with Y similar to 0.25 and [O/Fe] similar to 0.30. The MS-II hosts helium-rich (Y similar to 0.37-0.40) stars with metallicity ranging from [Fe/H] similar to -1.7 to -1.4. Below the MS knee (m(F160W) similar to 19.5), our photometry reveals that each of the two main MSs hosts stellar subpopulations with different oxygen abundances, with very O-poor stars ([O/Fe] similar to -0.5) populating the MS-II. Such a complexity has never been observed in previous studies of M-dwarfs in globular clusters. A few months before the launch of the James Webb Space Telescope, these results demonstrate the power of optical and near-infrared photometry in the study of multiple stellar populations in globular clusters.