The algorithms for the mathematical modeling to predict productivity of underground room-and-pillar mining systems are well-known and documented. These algorithms consider the time-varying relationships between mining equipment for a given geometry of operations as well as other constraints. This study presents a newly developed, user-friendly visual simulation computer tool for the Windows environment. This tool can be easily customized and utilized by field engineers and will help mine operators plan the optimum mining sequence for different mine geometries and equipment layouts. Program output includes monitoring of shift data, equipment utilization indices, and so forth. The simulation technique can be used with any environment. Use of the system is demonstrated in different mining equipment configurations. Development and validation of the system was aided by the Peabody Group. / Master of Science

Aggressive tax planning practices through schemes involving low-tax jurisdictions have been the target of the Organization for Economic Co-operation and Development (OECD) to end harmful tax competition and the so-called “race to the bottom”. Pillar Two Model Rules is the latest OECD way to achieve this objective. This thesis calls into question the design of these rules when applied to the realities of developing countries and argues that the idea that the GloBE Rules are a golden opportunity for source countries to raise significant additional tax revenues seems to fail when confronted with the circumstances of developing countries, mainly source countries. The design of the Pillar Two provisions makes countries’ tax policies intertwined. Therefore, developing countries are not exempt from Pillar Two consequences whether they choose or not to domestically implement its rules. The challenge is real for these countries, which must assess the potential impact on their tax competition and future tax revenues and determine whether the GloBE rules can help them achieve their sustainable development goals. This thesis attempts to give a perspective on what lies ahead for these countries in the Pillar Two new era.

Small-scale fracture behavior of four model alloy systems were investigated in the order of increasing microstructural complexity, namely: (i) a Ni-based Bulk Metallic Glass (Ni-BMG) with an isotropic amorphous microstructure; (ii) a single-phase high entropy alloy, HfTaTiVZr, with body centered cubic (BCC) microstructure; (iii) a dual-phase high entropy alloy, AlCoCrFeNi2.1, with eutectic FCC (L12) -BCC (B2) microstructure; and (iv) a Medium-Mn steel with hierarchical microstructure. The micro-mechanical response of these model alloys was investigated using nano-indentation, micro-pillar compression, and micro-cantilever bending. The relaxed Ni-BMG showed 6% higher hardness, 22% higher yield strength, and 26% higher bending strength compared to its as-cast counterpart. Both the as-cast and corresponding relaxed BMGs showed stable notch opening and blunting during micro-cantilever bending tests rather than unstable crack propagation. However, pronounced notch weakening was observed for both the structural states, with the bending strength lower by ~ 25% for the notched samples compared to the un-notched samples. Deformation behavior of HfTaTiVZr was evaluated by micropillar compression and micro-cantilever bending as a function of two different grain orientations, namely [101] and [111]. The [111] oriented micropillars demonstrated higher strength and strain hardening rate compared to [101] oriented micropillars. The [111] oriented micropillars showed transformation induced plasticity (TRIP) in contrast to dislocation-based planar-slip for the [101] oriented micropillars, explaining the difference in strain hardenability for the two orientations. These differences in deformation behavior for the two orientations were explained using Schmid factor calculations, transmission electron microscopy, and in-situ deformation videos. For the dual-phase AlCoCrFeNi2.1 high entropy alloy, the L12 phase exhibited superior bending strength, strain hardening, and plastic deformation, while the B2 phase showed limited damage tolerance during bending. The microstructure and deformation mechanisms were characterized for a few different medium-Mn steels with varying carbon (0.05-0.15 at%) and manganese (5-10 at%) content. The alloy with 10 at% Mn and 0.15 at% C (1015 alloy) showed hierarchical microstructure of retained austenite and ferrite with lamellae 200 nm to 300 nm wide. Micro-pillar compression at different strain levels for this alloy revealed that deformation in austenite is primarily accommodated through transformation to martensite, thereby increasing the strain hardening rate.

Yes / The family environment plays a crucial role in child physical activity (PA). Wearable activity trackers (wearables) show potential for increasing children's PA; however, few studies have explored families' acceptance of wearables. This study investigated the acceptability of using wearables in a family setting, aligning experiences with components of the Technology Acceptance Model and Theoretical Domains Framework. Twenty-four families, with children aged 5-9 years, took part in a 5-week study, where all members were provided with a Fitbit Alta HR for 4 weeks. Acceptability was measured using weekly surveys and pre-post-questionnaires. Nineteen families participated in a focus group. Quantitative and qualitative data were integrated using the Pillar Integration Process technique. Pillars reflected (1) external variables impacting wearable use and PA and (2) wearable use, (3) ease of use, (4) usefulness for increasing PA and other health outcomes, (5) attitudes, and (6) intention to use a wearable, including future intervention suggestions. Families found the Fitbit easy to use and acceptable, but use varied, and perceived impact on PA were mixed, with external variables contributing towards this. This study provides insights into how wearables may be integrated into family-based PA interventions and highlights barriers and facilitators of family wearable use. / This study is funded as part of a Ph.D. studentship by the Born in Bradford study. The Born in Bradford study receives core infrastructure funding from the Wellcome Trust (WT101597MA) and the National Institute for Health Research (NIHR), under its NIHR ARC Yorkshire and Humber (NIHR200166) and Clinical Research Network (CRN) research delivery support. For this piece of work, funding from the Sport England’s Local Delivery Pilot awarded Born in Bradford funding for this Ph.D. studentship. S.A.C. is supported by the NIHR Leicester Biomedical Research Centre—Lifestyle theme

Human induced pluripotent stem cell (iPSCs)-derived brain organoids have potential to recapitulate the earliest stages of brain development, serving as an effective in vitro model for studying both normal brain development and disorders. In this study, we demonstrate a straightforward approach of generating multiple cerebral organoids from iPSCs on a pillar plate platform, eliminating the need for labor-intensive, multiple transfer and encapsulation steps to ensure the reproducible generation of cerebral organoids. We formed embryoid bodies (EBs) in an ultra-low attachment (ULA) 384-well plate and subsequently transferred them to the pillar plate containing Matrigel, using a straightforward sandwiching and inverting method. Each pillar on the pillar plate contains a single spheroid, and the success rate of spheroid transfer was in a range of 95 - 100%. Using this approach, we robustly generated cerebral organoids on the pillar plate and demonstrated an intra-batch coefficient of variation (CV) below 9 – 19% based on ATP-based cell viability and compound treatment. Notably, our spheroid transfer method in combination with the pillar plate allows miniaturized culture of cerebral organoids, alleviates the issue of organoid variability, and has potential to significantly enhance assay throughput by allowing in situ organoid assessment as compared to conventional organoid culture in 6-/24-well plates, petri dishes, and spinner flasks.

Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: The organisations of the 21st century are confronted with continuous changes. It is necessary that organisations respond to these changes to improve the level of their performance. Although the number of change initiatives within organisations is the norm of the day, there are very few successes. One reason for this, the author maintains, is the tendency to usually overemphasise hard elements, and not attend adequately to the soft elements, although the latter often contribute to the success of the organisation. These soft elements are: staff, skills, style of leadership, and shared values. The aim of the study is to enhance organisational performance of the proposal engineering pillar (PEP) of Sizophumelela organisation. This department was chosen because most of the corrective actions requests (CAR) due to non performance at Sizophumelela are from PEP. The main objective of this study is to identify the areas of concern in PEP, to develop an understanding of organisational change and to propose interventions to address and solve problem areas and improve performance. The McKinsey 7S Model was used to analyse the effectiveness of this department at Sizophumelela, an electrical transformer manufacturer and refurbishment business. After the identification of problem areas, interventions are proposed to address these issues. In the literature review an overview of some organisational change models is provided and the limitations of these models are also indicated. Out of these models, the business process re-engineering (BPR) model was viewed as important for this study; hence some aspects of that model form part of proposed interventions to address the identified issues. The McKinsey 7S Model is preferred for the performance analysis of the PEP with its focus on: Strategy, structure, systems, staff, and style of leadership, skills, and shared values. The 7S model is viewed by the author as the model that has the greatest benefit, because both hard and soft elements are focused on. A comprehensive set of material available within the company was used and structured interviews were conducted with all members of the PEP team. With the help of this methodology the strengths and weaknesses were established and some recommendations were made. / AFRIKAANSE OPSOMMING: Die organisasies van die 21ste eeu kom voortdurend te staan voor veranderinge. Dit is nodig dat organisasies op hierdie veranderinge reageer om hul vlak van prestasie te verbeter. Hoewel die aantal veranderingsinisiatiewe binne organisasies vandag die norm is, is daar baie min suksesse. Een rede hiervoor, volgens hierdie outeur, is die neiging om gewoonlik harde elemente te oorbeklemtoon en nie genoeg aandag te gee aan die sagte elemente nie, hoewel laasgenoemde dikwels bydra tot die sukses van die organisasie. Hierdie sagte elemente is: personeel, vaardighede, leierskapstyl, en gedeelde waardes. Die doel van die studie is die verbetering van organisasieprestasie in die voorleggingsingenieurspilaar (PEP) van die Sizophumelela organisasie. Hierdie afdeling is gekies omdat die meeste van die versoeke om korrektiewe optrede (CAR) weens nieprestasie by Sizophumelela uit PEP afkomstig is. Die hoofdoelwit van hierdie studie is om die areas in PEP waaroor daar kommer bestaan, te identifiseer, begrip te ontwikkel van organisasieverandering en intervensies voor te stel om probleemareas op te los en prestasie te verbeter. Die McKinsey 7S Model is gebruik om die doeltreffendheid van hierdie afdeling by Sizophumelela te ontleed. Laasgenoemde is 'n besigheid wat elektriese transformators vervaardig en opknap. Na die identifisering van probleemareas word intervensies voorgestel om aan hierdie kwessies aandag te gee. In die literatuuroorsig word sommige modelle van organisasieverandering bekyk en die beperkinge van hierdie modelle word ook aangedui. Uit hierdie modelle word die model vir besigheidsprosesherontwerp (BPR) beskou as belangrik vir hierdie studie, dus vorm sommige aspekte van daardie model deel van voorgestelde intervensies ten opsigte van die geidentifiseerde kwessies. Die McKinsey 7S Model word verkies vir die prestasieontleding van die PEP met sy fokus op strategie, struktuur, stelsels, personeel, leierskapstyl, vaardighede en gedeelde waardes. Die 7S Model word deur die outeur beskou as die model met die grootste voordeel, aangesien dit fokus op beide harde en sagte elemente. 'n Omvattende stel materiaal wat binne die maatskappy beskikbaar is, is gebruik, en gestruktureerde onderhoude is gevoer met al die lede van die PEP span. Met behulp van hierdie metodologie is die sterk en swak eienskappe bepaal en sekere aanbevelings gedoen.

Os processos de união por soldagem entre peças e componentes metálicos são indispensáveis para nossa realidade tecnológica. O processo de soldagem por fricção com pino consumível conhecido como FHPP (Friction Hydro Pillar Processing) é um processo desenvolvido recentemente que ocorre no estado sólido através da fricção entre dois materiais e, com isso, reúne algumas vantagens sobre os processos convencionais de soldagem por fusão. Esta técnica apresenta grande potencial de aplicação na indústria de óleo e gás visando reparos de trincas e descontinuidades em equipamentos e estruturas de aços em geral. Apesar do grande potencial desta técnica, o estudo sobre a sua aplicação para produzir juntas com materiais dissimilares ainda é escasso se comparado com outras técnicas de soldagem. Desta forma, este trabalho tem como objetivo o desenvolvimento e a análise de juntas soldadas utilizando pinos com adição de níquel em chapas de aço com manganês, visando determinar a combinação entre material de pino e parâmetros de soldagem que forneça a junta com melhores características mecânicas e metalúrgicas. Os parâmetros de soldagem que variaram foram: velocidade de rotação e a força axial. Os materiais utilizados nos conjuntos soldados foram chapas de aço ao manganês, classificadas comercialmente como ASTM A516 grau 70, e barras de aço baixo carbono com adição de 3, 6 e 9% de níquel. A análise realizada sobre as juntas abrangeu a caracterização da microestrutura e das propriedades de dureza das regiões específicas da solda além dos ensaios mecânicos de dobramento, tração com micro-amostras e de tenacidade à fratura através do parâmetro CTOD. Todas as soldas tiveram bom preenchimento, porém alguns materiais de pino não proporcionaram boa ductilidade durante o dobramento. As falhas ocorridas durante o dobramento juntamente com os estudos da tenacidade à fratura na zona de ligação mostraram que o acúmulo de inclusões nesta região representa degradação das propriedades mecânicas localmente. Os ensaios de tração com micro-amostras indicam aumento da resistência mecânica na região do material depositado do pino e os valores de CTOD no material termomecânicamente afetado são significativamente maiores do que na zona de ligação, porém não alcançam os valores obtidos nos materiais como não processados. / The processes of union by welding between parts and metallic components are indispensable for our technological reality. The Friction Hydro Pillar Processing (FHPP) process is a newly developed process that occurs in the solid state through friction between two materials and thus has some advantages over conventional fusion welding processes. This technique presents great potential of application in the oil and gas industry aiming repairs of cracks and discontinuities in equipment and steel structures in general. Despite the great potential of this technique, the study of its application to produce joints with dissimilar materials is still scarce compared to other welding techniques. The aim of this work is the development and analysis of welded joints using rod with nickel addition in steel sheets with manganese, in order to determine the combination of rod material and welding parameters that provides the joint with better mechanical and metallurgical characteristics. The welding parameters that varied were: speed of rotation and axial force. The materials used in the welded assemblies were manganese steel plates, commercially classified as ASTM A516 grade 70, and low carbon steel with addition of 3, 6 and 9% nickel. The analysis of the joints included the characterization of the microstructure and the hardness properties of the specific regions of the weld in addition to the bend test, micro-tensile test and fracture toughness through the parameter CTOD. All welds were well filled, however, some rod materials did not provide good ductility during bend test. The failures during folding together with the fracture toughness studies in the bonding zone showed that the accumulation of inclusions in this region represents degradation of the mechanical properties locally. The micro-tensile test indicate increased mechanical strength in the region of the deposited material of the rod and the values of CTOD in the thermomechanically affected material are significantly higher than in the bonding zone, but do not reach the values obtained in the unprocessed material.

Este estudo tem por objetivo avaliar a possibilidade de confeccionar juntas soldadas pelo processo de soldagem por fricção com pino consumível (Friction Hydro Pillar Processing), em aço classificado como grau R4 de acordo com a norma IAC W22. As juntas soldadas foram produzidas com três diferentes forças axiais: 30 kN, 45 kN e 60 kN, e após a soldagem, submetidos a três diferentes tempos de tratamento térmico de revenimento: uma hora, duas horas e quatro horas, na temperatura de 650 C. A microestrutura predominantemente martensítica resultante destes processos, foi caracterizada através de microscopia óptica, e de um mapeamento de microdureza Vickers. As soldas tiveram suas zonas afetadas pelo processo mensuradas através do software de análise de imagens ImageJ, sendo observadas maiores zonas para menores forças axiais empregadas. Caracterizou-se ainda, o nível de tensões residuais oriundos do processo de soldagem através do método de difração de nêutrons, para uma solda produzida com força axial de 45 kN, em duas diferentes condições, no estado de como soldado e com revenimento de quatro horas após a soldagem. Com os resultados obtidos neste trabalho pode-se concluir que as juntas soldadas com a força de 60 kN apresentaram a melhor combinação de propriedades avaliadas, que são, um menor tamanho de zonas afetadas pelo processo, e manteve um bom nível de dureza mesmo após o revenimento. Todas as juntas soldadas apresentaram uma ótima união metalúrgica, e os diferentes tempos de tratamento térmico empregados promoveram alterações microestruturais e nas propriedades do material já esperadas para o tratamento térmico de revenimento. / The aim of this study is to evaluate the possibility of making joints welded by Friction Hydro Pillar Processing, in steel grade R4 according to IAC W22. The repairs were produced with three different axial forces: 30 kN, 45 kN and 60 kN, and after welding, subjected to three different tempering heat treatment times: one hour, two hours and four hours, at a temperature of 650 C. The predominantly martensitic microstructure resulting from these processes was characterized by optical microscopy and a Vickers microhardness mapping. The welds had their zones affected by the process measured through the ImageJ image analysis software, with larger zones being observed for smaller axial forces employed. It was also characterized the level of residual stresses from the welding process, through the neutron diffraction method, for a weld produced with axial force of 45 kN, in two different conditions, as welded and annealing for four hours after welding. With the results obtained in this work it can be concluded that the welded joints with the force of 60 kN presented the best combination of evaluated properties, which are, a smaller size of zones affected by the process, and maintained a good level of hardness even after the annealing. All the welded joints presented an excellent metallurgical bonding, and the different times of thermal treatment employed promoted microstructural changes and in the properties of the material already expected for the heat treatment of annealing.

The Master Thesis focuses on the description of two selected European pension systems, comparing primarily the structure and funding of Czech and Swiss pension models, the performance of pension funds and the conditions under which senior citizens are entitled to old age pension. The Thesis also arouses the question wheather the steps to reform the Czech pension system could be inspired by a foreign system and wheather the Swiss model would set a suitable example.

A parametric study is performed to investigate the parallel tunnel interaction. Three dimensional finite element analyses were performed to determine the effects of soil stiffness, pillar width and advancement level of the second tunnel on the behaviour of displacement, bending moment and shear force of the previously constructed tunnel. In the analysis PLAXIS 3D Tunnel geotechnical finite element package was used. This program allows the user to define the actual construction stages of a NATM tunnel construction. In the analysis, construction stages are defined in such a way that firstly one of the tunnels is constructed and the construction of the second tunnel starts after the construction of the first tunnel. The mid-length section of the first tunnel is investigated in six different locations and at seven different advancement levels in terms of displacement, bending moment and shear forces. It is found that, displacement and bending moment behaviour are more related with soil stiffness and pillar width than the behaviour of shear forces. While the level of advancement of the second tunnel causes different type of responses on the shear force behaviour, level of advancement does not affect the type of behaviour of displacements and bending moments. Another finding of the research is that pillar width has an evident influence on the behaviour of displacements and bending moment than the soil stiffness. It is also found that the interaction effect may be eliminated by increasing the pillar width equal or larger than an approximate value of 2.5 &ndash / 3.0 D (diameter) for an average soil stiffness value.